bai_tap_bd_hsg_ve_cacbohidrat

8/8/2019 bai_tap_bd_hsg_ve_cacbohidrat

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T S CHNG- TRNG PTTH CHUYN QUNG BNH

Cacbohidrat

i cng v danh php

1. Da trn cng thc chung gii thch tn gi cabohidrat.

Cng thc chung ca cabohidrat l Cn(H2O)m. Tn gi ny ch ra hai thnh phn cacng thc l cacbon (cacbo) v nc (hidrat).

2. Cho bit hai loi nhm chc c trong cabohidrat in hnh.

>C=O v -O-H. Cc cacbohidrat l cc polihydroxy andehit hoc xeton, trong nhm-OH lin kt vi cc nguyn t cacbon khng phi l cacbon ca nhm cacbonyl.

3. (a) Tn gi chung cho cc cacbohidrat l g ? (b) Tip v ng trong tn gi ca cccacbohidrat n gin l g ?

(a) ng. (b) -oz, i khi ng thuc loi xeton c c lip v ng -uloz.

4. nh ngha (a) saccarit, (b) monosaccarit, (c) disaccarit, (d) oligosaccarit v (e)polisaccarit.

(a) Saccarit l tn gi khc ca cacbohidrat v l thut ng c s dng khi phn loicc cacbohidrat. Ch saccarit xut pht t chsaccharum trong ting Latinh c nghal ng. (b) Monosaccarit l mt ng n. (c) Disaccarit c cu thnh t haimonosaccarit. d) Oligosaccaritcu thnh t 3-10 monosaccarit. (e) Polisaccaritccu thnh bi trn 10 monosaccarit.

5. (a) Cho bit quan h v thnh phn nguyn t gia hai monosaccarit v mt disaccarittng ng. (b) Vit cng thc chung ca cc disaccarit. (c) Vit phng trnh thy phntrisaccarit di tc dng ca enzim (s dng ch thay cng thc).

(a) S kt hp hai phn t monosaccarit hnh thnh nn mt phn t disaccarit ngthi vi vic gii phng mt phn t nc. (b) Cn(H2O)n-1. (c) Trisaccarit + 2H2O

enzim 3 monosaccarit.

6. S dng tip v ng -oz trong tn gi mi monosaccarit sau : (a)HOCH2CHOHCOCH2OH, (b) HOCH2(CHOH)4CHO v (c) HOCH2(CHOH)4CH2CHO.

Ngoi tip v ng trn, chng ta s dng cc tip u ng ando-, xeto- ch nhm

cacbonyl tng ng v -di-, -tri-, ... ch s nguyn t cacbon trong mch, nh vy(a) xetotetroz, (b) andohexoz v (c) deoxyandopentoz (deoxy cho bit thiu mtnhm -OH trn mch). Mt cch chnh xc hn th cht ny thuc loi 2-deoxyandopentoz (thiu mt nhm -OH trn nguyn t cacbon s 2).

7. Vit cng thc phn t cho (a) mt tetroz tetrasaccarit v (b) mt polypentosit(pentosan).

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(a) Theo lp lun ca bi tp 23.5a chng ta c 4C 4(H2O)4C16(H2O)13 + 3H2O, haycng thc phn t ny c th vit l C16H26O13. (b) Polysaccarit c hnh thnh t nphn t monosaccarit v loi i nphn t H2O, nh vy cng thc phn t ca loi hpcht cho trn s l [C5(H2O)4]n hay (C5H8O4)n.

8. Xc nh cng thc ca glucoz t cc d kin sau : Thnh phn % cc nguyn t l C =40,0 ; H = 6,7 ; O = 53,3. Dung dch cha 9,0g glucoz trong 100g nc ng c -0,93oC.

C : H : O =16

3,53

1

7,6

12

0,40== =1: 2 : 1

cng thc nguyn (CH2O)n, M = 30n

18093,0.100

1000.9.86,1M == n =

30

180= 3,

Cng thc phn t ca glucoz l C6H12O6 (hexoz).

Ha hc lp th9. (a) Vit cng thc Fischer cho cc ng phn D v L ca mt ng n gin nht. (b)

Vit k hiu ch chiu quay cc ca cc ng phn i quang ny. (c) Cho bit cu hnhtuyt i ca mi ng phn.

(a) ng l hp chtpolyhidroxy nn c ti thiu hai nhm -OH, ng n gin nhtphi l mt trioz (glixerandehit) (b) Fischer p t cu hnh D cho cc ng phnenan quay phi, nh vy D l (+), L l (-). (c) D l R v L l S.

CHO

OH

CH2OH

H

D (OH bn phi)

CHO

H

CH2OH

HO

L (OH bn tri)

10. Ch r cu hnh D/L cho cc cng thc chiu Fischer di y ca glixerandehit.CH2OH

H

CHO

HO(a)

OH

CHO

H

HOH2C(b)

CHO

CH2OH

OH

H(c)

Trc ht chng ta xc nh cu hnh tuyt i R/S ca chng v vi s tng ng R lD v S l R ta xc nh c cu hnh D/L. Vi trt t hn cp -OH > -CHO >-CH2OH ta c (a) R hay D, (b) R hay D, (c) S hay L. Ch rng trong cc cng thc(a) v (c) nguyn t H nm trn ng ngang.

11. (a) Vit cng thc cu to ca mt ng xetozn gin nht. (b) Cho bit s khcnhau v cu to gia ng xetoz ny v glixerandehit (khng k n loi hp chtcacbonyl).

(a) HOCH2COCH2OH. (b) ng xetoz ny khng c tm bt i.

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12. (a) Trong andotetroz c bao nhiu tm bt i ? (b) Vit cng thc Fischer cho cc ngphn i quang ca mt andotetroz v xc nh cu hnh D/L ca chng.

(a) C hai tm bt i : HOCH2-*CHOH-*CHOHCHO. (b) Theo qui c cu hnh Dca ng ng vi nhm -OH trn C* c ch s v tr cao nht pha bn phi v cuhnh L ng vi nhm -OH trn C* c ch s v tr cao nht pha bn tri :

CHO

OHH

D - erythro

CH2OH

OHH

CHO

HHO

L - erythro

CH2OH

HHO

CHO

HHO

D - Threo

CH2OH

OHH

CHO

OHH

L -Threo

CH2OH

HHO

13. Cho bit s khc nhau gia D-erythro v D-threo khi chng b oxi ha nh nhng.

Khi oxi ha nh nhng th -CH2OH v -CHO chuyn thnh nhm -COOH, to ra ccng phn dia ca axit tactaric. Dng threo to mt ng phn i quang hot ngquang hc, trong khi dng erythro to mt ng phn mezo khng hot ng quanghc.

OH

C C

H

HOH2C

D - threo

H

OH

CHO[O]

OH

C C

H

HOOC

Axit D -(-)-tactaric

H

OH

COOH

OH

C C

H

HOH2C

D - erythro

OH

H

CHO[O]

OH

C C

H

HOOC

Axit mezo-tactaric

OH

H

COOH

14. Cho bit s khc nhau gia D-erythro v D-threo khi chng b kh.

Nhm -CHO b kh thnh nhm -CH2OH to ra 1,2,3,4-butantetrol. Threo to cmt ng phn enan hot ng quang hc trong khi erythro to ng phn mezokhng hot ng quang hc.

OH

C C

H

HOH2C

D - threo

H

OH

CHO[Kh] OH

C C

H

HOH2C

D-1,2,3,4-butantetrol

H

OH

CH2OH

OH

C C

H

HOH2C

D - erythro

OH

H

CHO[Kh] OH

C C

H

HOH2C

mezo-1,2,3,4-butantetrol

OH

H

CH2OH

15. Ti sao cc ng phn ca axit tartric v 1,2,3,4-butantetrol hot ng quang hc cxp vo dy D ?

Trong sut qu trnh oxi ha hoc kh cu hnh ca nguyn t C bt i khng thayi, do cu hnh D ban u c bo ton.

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16. Cho bit nh ngha ca thut ng epime v dng cu hnh erythro, threo minh hanh ngha ny .

Thut ng epime c s dng ch cc ng phn dia c nhiu tm bt i, nhngch c mt cacbon bt i c cu hnh khc nhau. D-threo v D-erythro l epime do cuhnh C2 ca chng khc nhau.

17. (a) Cc hp cht mch h sau y c bao nhiu nguyn t cacbon bt i : (i)andohexoz nh glucoz v (ii) 2-xetohexoz nh fructoz ? (b) Andohexoz c baonhiu ng phn quang hc ?

(a) (i) bn : HOCH2*CHOH*CHOH*CHOH*CHOHCHO(ii) ba : HOCH2*CHOH*CHOH*CHOHCOCH2OH

(b) Do c bn nguyn t cacbon bt i nn s c 24 = 16 ng phn quang hc.

18. Loi andohexoz mch h no c 8 ng phn quang hc ?

Deoxyandohexoz c ba nguyn t cacbon bt i nn s c 23 = 8 ng phn quanghc.

Phn ng

19. (a) Cho bit kh nng phn ng, hin tng v sn phm to thnh khi andohexoz v 2-xetohexoz tc dng vi : (i) thuc th Tollens, (ii) thuc th Fehling, (iii) thuc thBenedict v (iv) Br2/H2O. (b) Sn phm hnh hnh t andohexoz c xp vo loino ?

(a) Cc thuc th ny u c tc dng oxi ha nhm -CHO thnh -COOH hoc mui

ca n. (i) Thuc th Tollens l hp cht phc Ag(NH3)2+, c hai cht u tc dng vithuc th ny to kt ta trng bc. S d ng xeto phn ng c l do trong mitrng kim chng chuyn ha thnh mt ng ando (xem bi 23.23). (ii) Thucth Fehling l phc Cu2+ tartrat trong NaOH, c hai cht u tc dng vi thuc th nylm nht mu xanh ca dung dch thuc th v hnh thnh kt ta Cu 2Omu gch.(iii) Thuc th Benedict l phc Cu2+ xitrat trong NaOH, hin tng v sn phm hnhthnh ging nh phn ng ca thuc th Fehling. (iv) Ch ng ando phn ng clm mt mu da cam ca dung dch brom. (b) Sn phm hnh thnh t c hai loing trn u thuc loi axit andonic HOCH2-CHOH-CHOH-CHOH-CHOH-COOH.

20. Cho bit sn phm to thnh khi cho andotetroz tc dng vi HNO3. HNO3 oxi ha ng thi nhm -CHO v -CH2OH thnh nhm -COOH, sn phm to

thnh thuc loi axit andaric HOOC-CHOH-CHOH-COOH.

21. Cho bit loi phn ng v sn phm to thnh khi cho andotetroz v xetotetroz tcdng vi H2/Ni, dung dch NaBH4 hoc Na/Hg.

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Cc tc tc nhn ny u ng vai tr cht kh nhm >C=O thnh nhm >CHOH, snphm to thnh l mt anditolHOCH2-CHOH-CHOH-CH2OH.

22. Vit cng thc chiu Fischer ch r cc ng phn lp th hnh thnh khi kh mt D-andotetroz v mt D-xetotetroz.

D-andotetroz v sn phm kh anditolu c hai nguyn t cacbon bt i (xem bi23.14), D-xetotetroz ch c mt nguyn t cacbon bt i nhng qu trnhkh to nguyn t cacbon bt i th hai do vy sn phm kh cha hn hp haing phn dia anditol.

CH2OH

O

D - xetotetroz

CH2OH

OHH

CH2OH

OH

mezo-anditol

CH2OH

OHH

H

CH2OH

H

D-anditol

CH2OH

OHH

HO

+

23. Do tn ti mt cn bng gia andohexoz v 2-xetohexoz trong mi trng kim m 2-

xetohexoz phn ng c vi thuc th Fehling (xem bi 23.19). (a) Gii thch s tnti ca cn bng ny. (b) Gii thch s hnh thnh hai ng phn dia andohexoz.

(a) S tautome ha trong mi trng kim ca andohexoz v 2-xetohexoz to mttrng thi trung gian chung, nh m cn bng gia chng c thit lp.

C

C

C

andoz

OHH

C

OH

C

endiol

OHH

C

CH

O

xetoz

OHH

O

OHH

H OHH OHH

(b) Khi hnh thnh li andoz t endiol, H+ c th tn cng vo C2-sp2 t hai pha khcnhau to hai ng phn epime khc nhau cu hnh ca C2.

C

OH

C

endiol

OHH

2C

OHH C

C

C

Cc ng phn epime C2

OHH

O

OHH

H C

C

C OHH

O

HHO

H

+sp2 - khng bt i

sp3 - bt i

24. (a) Cho bit cc sn phm to thnh khi cho HIO4 tc dng vi (i) HOCH2-CHOH-CHOH-CHOH-CHOH-CHO (andoz) v (ii) HOCH2-CHOH-CHOH-CHOH-CO-

CH2OH (2-xetoz). (b) Da trn loi phn ng ny trnh by mt phng php n ginphn bit hai ng phn ny.

(a) HIO4 ng vai tr mt tc nhn oxi ha : (i) -CHO, >CHOH chuyn thnh HCOOHv -CH2OH chuyn thnh H2C=O, vy sn phm l : 5HCOOH + H2C=O, (ii) >C=Ochuyn thnh CO2, vy sn phm l : 2H2C=O + 3HCOOH + CO2. (b) Nhn bit CO2da trn phn ng to kt ta trng CaCO3 vi dung dch Ca(OH)2 d, t nhn bitc xetoz.

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25. (a) Cho bit cc cht trung gian v sn phm to thnh khi cho D-threo tc dng viPhNHNH2. (b) Khi D-erythro tham gia phn ng ny th sn phm l g ? Gii thch snphm thu c. (c) C th kt lun iu g khi tin hnh phn ng ny vi cc ng phnepime.

(a) Phn ng ca D-threo :CHO

HHO

D - Threo

CH2OH

OHH+ PhNHNH2

C

HHO

CH2OH

OHH

H NNHPh

PhNHNH2

-PhNH2,-NH3

C

C O

CH2OH

OHH

H NNHPh

+ PhNHNH2

C

C NNHPh

CH2OH

OHH

H NNHPh

osazon

(b) D-erythro cng to mt osazon ging nh trn. Cu hnh C2 trong hp cht ngban u khng quan trng do n b oxi ha thnh nhm >C=O to mt xeton gingnhau t c hai loi ng trn. (c) Ni chung cc ng phn epime-C2 ca ng andoto ra cng mt osazon.

26. Cho bit osazon hnh thnh t 2-xetohexoz v nh gi kh nng hnh thnh sn phmny.

Phn ng oxi ha 1o-OH d dng hn 2o-OH, nn s hnh thnh osazon din ra d dnghn.

C

C NNHPh

CH2OH

OH)3(H

H NNHPh

27. (a) 2-xetohexoz c tng hp t osazon ca andoohexoz nh th no ? (b) Phngphp ny chuyn ha glucoz thnh fructoz, vy bn c th nhn xt g v cu hnhca cc nguyn t C3, C4, C5 ca andohexoz v ca 2-xetohexoz ?

(a) Nhm phenylhidrazinyl ca osazon chuyn qua PhCHO to ra PhCH=NNHPh vmt hp cht cacbonyl gi l oson, sau nhm andehit b kh d dng (trong khinhm xeton khng b kh) to thnh 2-xetohexoz :

C

C NNHPh

CH2OH

OH)3(H

H NNHPh

- 2PhCH=NNHPh

+ PhCHO

C

C O

CH2OH

OH)3(H

H O

oson

Zn/HAc

CH2

C O

CH2OH

OH)3(H

OH

(b) Cu hnh ca cc nguyn t C3, C4, C5 khng thay i trong qu trnh phn ng, dovy cc ng phi c cu hnh ging nhau cc nguyn t cacbon ny.

28. (a) Vit hai sn phm l ng phn hnh thnh trong phn ng gia D-threo vNaCN/HCN. (b) Kt qu ca phn ng ny c nh hng g n mch cacbon ?

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(a) Sn phm l cc ng phn xianohidrin C2-epime :

C

HHO

D - ThreoCH2OH

OHH+ NaCN/HCN

OH C

HHO

CH2OH

OHH

HO C

HHO

CH2OH

OHH

H

+

H

CN CN

OH

(b) Mch cacbon c s nguyn t cacbon tng thm mt.

29. Ti sao hai ng phn epime trong bi 23.28 li c to thnh vi hm lng khngbng nhau ?

Nguyn t C2 bt i trong cc ng phn epime hnh thnh t nhm cacbonyl, qutrnh tn cng vo hai pha ca nhm ny chu nh hng khng gian lm cho tc qu trnh din ra khc nhau nn sn phm to thnh c hm lng khc nhau.

30. Cho bit s bin i cu trc ca (a) glucoz v (b) fructoz khi phn ng lin tc vi (1)NaCN/HCN, (2) H3O+, (3) HI/P.

Glucoz v fructoz phn ng tng t nh nhau, bc mt l cng thm mt nhm-CN vo nhm >C=O to ra mt xianohidrin, bc hai thy phn nhm -CN thnhnhm -COOH, bc ba kh tt c cc nhm -OH thnh -H v sn phm to thnh lmt axit ankylcacboxilic. (a) Thu c axit heptanoic khng nhnh, iu ny chng tglucoz l mt andohexoz. (b) Thu c axit 2-metylhexanoic mch nhnh, iu nychng t fructoz l mt 2-xetohexoz.

31. Cho bit cc bc chuyn ha t andopentoz thnh andohexoz theo phng phpKiliani-Fischer, bit rng bc u tin ca phng php ny l phn ng cng HCN vonhm >C=O.

Cc bc chuyn ha :

HC

(HC OH)2

HC

D -andopentoz

CH2OH

OH+ NaCN/HCN

O HC

(HC OH)2

HC

CH2OH

OH+ H3O

+

CN

OH HC

(HC OH)2

HC

CH2OH

OH

COOH

OH HC

(HC OH)2

HC

CH2OH

C

OH

O

O+ Na/Hg

- CO2

HC

(HC OH)2

HC

CH2OH

OH

HC

OH

O

xianohidrin axit glyconic -lacton D -andohexoz

Lu rng (i) -lacton cng sinh ra ng thi vi -lacton v chng to thnh hnhp khng th tch ra khi nhau. (ii) Sn phm thu c cui cng l hn hai ngphn C2-epime.

32. (a) Giai on no trong tng hpKiliani-Fischerl tt nht tch hai ng phn dia ?(b) Hin nay ngi ta ci tin phng php Kiliani-Fischer nh th no ? (c)

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Andohexoz thu c thuc dy cu hnh D hay L ? (d) C th p dng phng ny tng mch cho xetoz mch thng c khng ?

(a) Giai on tt nht l tch cc ng phn dia ca axit glyconic, chng c tch radi dng mui kt tinh. (b) Cc xianohidrin c kh trc tip thnh andoz bng qutrnh thy phn c xc tc thch hp. (c) Dy D, do qu trnh phn ng khng lm thay

i cu hnh ca nguyn t cacbon quy nh dy D/L. (d) Khng, do s to ra axitglyconic mch nhnh.

33. (a) Cho bit cu to cc cht trong s chuyn ha di y, trong B l sn phmtch ra t cn bng thun nghch vi A :

Andoz OH/Br 22 A pyridin B +H C Hg/Na D

(b) Cu trc mch thay i nh th no sau cc bc chuyn ha ny ?

(a) A l axit andonic [xem bi 23.19(b)], B l ng phn C2-epime ca A, C l lacton,D l sn phm kh ca C v l ng phn C2-epime ca andoz ban u. (b) y l

mt qu trnh epime ha.

34. (a) Cho bit cu to cc cht trong s chuyn ha di y:Andohexoz OH/Br 22 E 3C a C O F )III(Fe/OH 22 G

(b) Cu trc mch thay i nh th no ? (c) Phng php ny c tn gi l g ? (d) Chokt lun v kh nng hnh thnh ng phn epime.

(a) E l axit andonic, F l mui canxi ca n [HOCH2-CHOH-CHOH-CHOH-CHOH-COO]2Ca, G l mt andopentoz HOCH2-CHOH-CHOH-CHOH-CHO. (b) Mchcacbon gim bt mt nguyn t cacbon. (c) Phng php oxi ha v decacboxilat hany c tn gi l thoi phn Ruff . (d) Trong qu trnh chuyn ha ch c nhm -

CHOH b oxi ha thnh nhm -CH=O, cn cc nguyn t cacbon bt i khc khngtham gia nn khng c s thay i cu hnh no. Nh vy khng th c ng phnepime hnh thnh.

35. (a) Cho bit cu to cc cht trong s chuyn ha di y:Andohexoz baz/OHNH2 H NaOAc/OAc2 J MeOH/MaOMe K

(b) Gii thch bc cui cng. (c) Cu trc mch thay i nh th no ? (d) Phngphp ny c tn gi l g ? (e) Cho kt lun v kh nng hnh thnh ng phn epime.

(a) H l mt oxim HOCH2-(CHOH)4-CH=NOH, I l mt oxim b axetyl ha honton AcCH2-(CHOAc)4-CH=NOAc, J l sn phm ca I tch bt mt HOAc : AcCH2-(CHOAc)4-C N, K l mt andopentoz HOCH2-CHOH-CHOH-CHOH-CHO. (b)Bc ny xy ra s chuyn este, axetyl trong J chuyn thnh metyl axetat v gii phngcc nhm -OH, tip sau l qu trnh tch HCN. (c) Mch cacbon gim bt mtnguyn t cacbon. (d) Thoi phn Wohl. (e) Trong qu trnh chuyn ha ch c nhm -CHOH b oxi ha thnh nhm -CH=O, cn cc nguyn t cacbon bt i khckhng tham gia nn khng c s thay i cu hnh no. Nh vy khng th c ngphn epime hnh thnh.

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Cu trc

36. Tin hnh thoi phn Ruff mt andohexoz hai ln to ra mt andotetroz, oxi haandotetroz bng HNO3 to thnh axit meso-tartaric. Andohexoz ban u thuc dy Dhay L ?

Cu hnh ca cc nguyn t C4

v C5

ca andohexoz c gi nguyn trongandotetroz. V sn phm sinh ra l axit meso-tartaric nn hai nhm -OH trn ccnguyn t C ny phi cng pha. Nh vy c hai trng hp c th xy ra. Nu chngcng pha phi th andohexoz c cu hnh D, cn nu chng cng pha tri thandohexoz c cu hnh L :

(CHOH)2

H4C OH

H5C

D -andohexoz

CH2OH

OH

D -andotetroz axitmeso tartaric L -andotetroz L -andohexoz

CHO

CHO

H4C OH

H5C

CH2OH

OH

COOH

H4C OH

H5C

COOH

OH2Ruff + HNO3

CHO

HO4C H

HO5C

CH2OH

H

(CHOH)2

HO4C H

HO5C

CH2OH

H

CHO

+ HNO3 2Ruff

37. D-andohexoz no khi b oxi ha bi HNO3 to ra axit meso andaric ?

Axit andaric c mt phng i xng gia C3 v C4, v vy andohexoz cng phi cmt phng i xng gia C2, C3, C4 v C5. Hai kh nng c th xy ra :

H3C

H4C OH

H5C

D -Alloz

CH2OH

OH

H2C

+ HNO3 + HNO3

OH

OH

CHO

H3C

H4C OH

H5C

Axitmeso allaric

COOH

OH

H2C

OH

OH

COOH

HO3C

HO4C H

H5C

Axitmeso galactaric

COOH

OH

H2C

H

OH

COOH

HO3C

HO4C H

H5C

D -Galactoz

CH2OH

OH

H2C

H

OH

CHO

38. Tin hnh mt ln thoi phn Ruff vi D- alloz v D-galactoz sau oxi ha bngHNO3 to ra tng ng mt ng phn meso v mt ng phn hot ng quang hc caaxit pentaandaric. Kt qa ny c ph hp vi kt qu tm c bi 23.37 hay khng ?

Ph hp. Khi C2 ca alloz chuyn thnh nhm -CHO do phn ngRuff, cc nguyn tC3, C4 v C5 vn phi gi nguyn tnh i xng ca cu hnh khi oxi ha th snphm to ra l axit meso andaric, nh vy cc nhm -OH phi cng pha v v allozthuc dy D nn chng cng pha bn phi. Trong galactoz, tnh i xng b phhy khi C2 chuyn thnh nhm -CHO, nh vy cc nhm -OH khng nm cng pha.

39. C cc D-andohexoz no khc to c mt (a) ng phn hot ng quang hc v (b)ng phn mezo ca axit pentaandaric khi chng chng cng tri qua cc giai on phnng ging nh bi 23.38 ?

Xem hnh 23-1

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Hnh 23-1

C

C OH

C

(a)

CH2OH

OH

C

H

H

CHO

HO

HO

H

H

C

C OH

C

CH2OH

OH

C

H

OH

CHO

H

HO

H

H

C

C H

C

CH2OH

OH

C

H

H

CHO

HO

HO

HO

H

C

C OH

C

(b)

CH2OH

OH

C

OH

H

CHO

HO

H

H

H

C

C H

C

CH2OH

OH

C

OH

H

CHO

HO

H

HO

H

C

C H

C

CH2OH

OH

C

OH

OH

COOH

H

H

HO

H

40. Mi mt andohexoz nh D-alloz, D-glucoz v D-taloz u to c axit meso-heptandaric sau khi oxi ha mt trong hai sn phm ca phn ng tng mchKiliani. Xcnh cu to ca andohexoz v axit meso, bit taloz l ng phn C2-epime cagalactoz.

C ba axit meso-heptaandaric nh trong hnh 23-2.

C

C OH

C

CH2OH

OH

C

OH

OH

CHO

H

H

H

H

2. HNO3

1. KilianiC

C OH

C

COOH

OH

C

OH

OH

C

H

H

H

H

OH

COOH

H

Mt phng

i xng

D-alloz

C

C OH

C

CH2OH

OH

C

H

OH

CHO

H

HO

H

H

2. HNO3

1. KilianiC

C OH

C

COOH

OH

C

H

OH

C

H

HO

H

H

OH

COOH

H

Mt phng

i xng

D-glucoz

C

C H

C

CH2OH

OH

C

H

H

CHO

HO

HO

HO

H

2. HNO3

1. KilianiC

C H

C

COOH

OH

C

H

H

C

HO

HO

HO

H

OH

COOH

H

Mt phng

i xng

D-taloz

41. Xc nh cu to ca D-arabinoz, bit andoz ny thu c t phn ng thoi phnRuffca D-mannoz (mt ng phn C2-epime ca glucoz).

Cu to ca D-arabinoz :

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C

C OH

C

CH2OH

OH

C

H

H

CHO

HO

HO

H

H

Ruff

D-mannoz

C

C OH

C

CH2OH

OH

CHO

HHO

H

H

D-arabinoz

42. Vit cu to ca D-riboz, mt cu t ca ARN, bit rng D-riboz v D-arabinoz toosazon ging nhau.

Do D-riboz v D-arabinoz to osazon ging nhau nn chng l ng phn C2-epime.CHO

OHH

D - Riboz

OHH

C

C NNHPh

C

OHH

H NNHPh

osazon

OH

CH2OH

H H

CH2OH

OH

CHO

HHO

D - arabinoz

OHH

OH

CH2OH

H

43. Cc andopentoz l D-xyloz v D-lyxoz to osazon ging nhau v khi b oxi ha thtng ng to mt ng phn mezo v mt ng phn hot ng quang hc ca axitandaric. Vit cng thc cu to ca chng.

Chng l ng phn C2-epime. Xyloz to axit meso andaric do c i xng cu hnh C2, C3 v C4.

CHO

OHH

D - Xyloz

HHO

OH

CH2OH

H

COOH

OHH

Axitmeso xylaric

HHO

OH

COOH

HHNO3

CHO

HHO

D - Lyxoz

HHO

OH

CH2OH

H

COOH

HHO

Axit D-lyxaric

HHO

OH

COOH

HHNO3

44. Vit cng thc cu to cho hai vng lacton su cnh hnh thnh t axit glucaric (axitandaric ca glucoz).

Cng thc :

C

C OH

C

COOH

OH

C

H

OH

COOH

H

HO

H

H

Axit glucaric

H+C

C OH

C

COOH

O

C

H

OH

C

H

HO

H

H

Lacton A

O

C

C OH

C

C

OH

C

H

O

COOH

H

HO

H

H

Lacton BO

+

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45. Kh cc lacton trong bi 23.44 to thnh axit andonic, lacton ca axit ny c x l viNa/Hg v CO2 to thnh andohexoz. Vit cu to ca mi andohexoz to thnh v chobit cu hnh ca chng thuc dy D hay L.

Dy chuyn ha to andohexoz ca mi lacton :

C

C OH

C

COOH

OH

C

H

OH

CH2OH

H

HO

H

H

- H2OC

C OH

C

C

OH

C

H

O

CH2OH

H

HO

H

H

O

Akh Na/Hg

CO2

C

C OH

C

CHO

OH

C

H

OH

CH2OH

H

HO

H

H

C

CHO

C

CHO

HO

C

H

HO

CH2OH

H

OH

H

H

L- Guloz

C

C OH

C

CH2OH

OH

C

H

OH

COOH

H

HO

H

H

- H2OC

C OH

C

CH2OH

O

C

H

OH

C

H

HO

H

H

Bkh Na/Hg

CO2

C

C OH

C

CH2OH

OH

C

H

OH

CHO

H

HO

H

H

D-glucoz

O

46. Emil Fischer, cha ca nghnh ha hc cacbohidrat, s dng L-guloz tng hp(ng bit cu to ca n) xc nh cu to cc ng phn epime D-glucoz v D-mannoz (cu to ca cc cht ny cha thit lp c). ng suy lun iu ny nhth no ?

Oxi ha L-guloz v D-glucoz to thnh cng mt axit andaric (xem cng thc trong

trong bi 23.44). Fischer kt lun rng L-guloz v D-glucoz c cng cu hnh cacacbon bt i v ch khc nhau l nhm -CHO ca L-guloz pha di, cn nhm-CHO ca D-glucoz pha trn. Do bit cu to ca L-guloz nn suy ra cu toca D-glucoz, ng thi cu to ca D-mannoz cng c bit do D-glucoz v D-mannoz l ng phn C2-epime.

47. (a) L-andoz no c th to axit andaric ging nh D-mannoz ? (b) Axit andaric ca D-v L-mannoz quan h vi nhau nh th no ?

(a) Khng. (b) Chng l cc ng phn i quang (enan), xem hnh 23-3.

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H.23-3 :

HHO

D - Mannoz

OHH

OH

CH2OH

H

Axit D-andaric

HNO3

CHO

HHO

HHO

OHH

OH

COOH

H

COOH

HHO

Axit L-andaric

OHH

HHO

H

COOH

HO

COOH

OHH

OHH

L- Mannoz

HHO

H

CH2OH

HO

CHO

OHH

HNO3

H 23-4:

OHHO

L- idoz

OHH

H

CH2OH

HO

CHO

OHH

48. (a) Ti sao khi nghch chuyn cu hnh C5 ca D-glucoz li khng thu c L-glucoz ?(b) S nghch chuyn ny li to ra L-idoz, vit cng thc cu to ca L-idoz.

(a) thu c L-glucoz (ng phn i quang ca D-glucoz) cn phi nghchchuyn cu hnh ca tt c cc nguyn t cacbon bt i trong D-glucoz. (b) Xemhnh 23-4.

49. (a) So snh v gii thch s khc nhau khi cho mt andohexoz v mt andehit tc dungvi lng d ROH trong HCl khan. (b) Cho bit tn gi chung ca sn phm sinh ra tandohexoz v tn gi ring nu andohexoz l glucoz.

(a) Andehit phn ng vi 2 ng lng ROH to ra mt axetal, andohexoz chphn ng vi 1 ng lng ROH. S d c s khc nhau ny l v andohexoz lmt semi axetal do phn ng cng khp vng ni phn t gia -OH v -CHO, nn chcn thm mt ng lng ROH to axetal. iu ny cng chng t rngandohexoz tn ti ch yu dng vng (b)glycozitvglucozit.

50. (a) Gii thch s t hnh thnh hai ng phn dia ca glucoz trong dung dch nc. (b)Vit cu to v gi tn cc ng phn dia ny. (c) Cc ng phn dia trong trng hpny c gi l g ?. (d) C th to bao nhiu metyl glucozit ?

(a) Khi nhm -CH=O chuyn thnh semiaxtal vng th C1 ca n cng tr thnh mttm bt i v hnh thnh nn hai ng phn, mt c nhm -OH bn phi v mt bn tri. (b) Xem hnh 23-5, -D-glucoz c C1-OH bn phi v -D-glucoz c

C1-OH bn tri. (c) ng phn anome. (d) Hai. -D-glucoz to ra metyl -D-glucozit v -D-glucoz to ra metyl -D-glucozit.

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Hnh 23-5 :

C

C OH

C

CH2OH

OH

C

H

OH

C

H

HO

H

H

glucozmch h

C

C OH

C

CH2OH

C

H

OH

C

H

HO

H

H

-D-glucoz

O

OHH

C

C OH

C

CH2OH

C

H

OH

C

H

HO

H

H

-D-glucoz

O

HHOOH

51. C phi cc ng phn anome ca D-glucoz c cng gi tr gc quay cc ring nhngngc du ?

Khng, hin tng ny ch xy ra vi cc ng phn enan, ng phn anome khngphi l ng phn enan.

52. ng phn epime v anome khc nhau nh th no ?

ng phn anome l ng phn C1-epime.

53. Gi tn ng phn enan ca -D-(+)-glucoz.

-L-(-)-glucoz. Theo nh ngha th ng phn -enan c nhm -OH semiaxetalcng pha vi nhm -OH trn nguyn t C qui nh cu hnh D/L.

54. Ti sao cc andoz phn ng c vi dung dch Fehling v PhNHNH2 nhng li khngphn ng vi NaHSO3.

Cc andoz trong t nhin tn ti cn bng gia dng , v mch h, trong chc dng mch h l c nhm andehit nhng nng ca dng ny rt thp (khong0,02%). Cc phn ng trn u xy ra vi nhm andehit nhng c khc bit mt cht lphn ng ca dung dch Fehling v PhNHNH2dinra mt chiu lm chuyn di cnbng ca dng v v pha mch h, v vy phn ng c xy ra. Trong khi phnng ca NaHSO3 l phn ng thun nghch, khi nng andehit nh th phn ng nykhng th xy ra.

55. Glycosit c phn ng vi thuc th Tollens hoc Fehling hay khng ?

Khng, glycozit l mt semiaxetal bn trong mi trng kim, chng khng c nhm-CH=O nn khng kh c.

56. (a) Vit hai sn phm ca phn ng gia mt andohexoz vi lng d Ac2O/NaOAc.(b) Nhng sn phm ny c phn ng vi dung dch Fehling hoc PhNHNH 2 hay khng ?Gii thch.

(a) Sn phm l - v -pentaaxetat ca semiaxetal, khng c pentaaxetat caandehit. C1-OH ca ng phn anome b axetyl ha, trong khi -OH tham gia to

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vng khng cn c th axetyl ha. (b) Khng, do cc pentaaxetat khng b thyphn trong mi trng kim, chng khng c nhm -CH=O t do.

57. Vit hai sn phm ca phn ng gia mt andohexoz vi lng d (MeO)2SO2 hocMeI trong dung dch NaOH v gii thch s hnh thnh cc sn phm ny.

Cc nhm -OH ca ng c tnh axit mnh hn so vi cc nhm -OH ca ru do nhhng hiu ng cm ng m gia chng. Nm nhm -OH t do s chuyn thnh ccankoxi thng qua phn ng th SN2 vi tc nhn metyl c hot ha. Chng ta lithu c sn phm l hn hp ca - v -pentametyl glycozit.

58. Loi vng thng gp cc semiaxetan ny l g ? Gi tn mi loi.

Vi mc ch to ra cc vng bn, vi tc hnh thnh nhanh th loi vng thnggp c 5 hoc 6 nguyn t, trong mt nguyn t l oxi. Cc semiaxetan vng nmcnh c gi lfuranozv cc semiaxetan vng su cnh c gi lpyranoz.

59. (a) Andoz nh nht c th hnh thnh nn semiaxetan vng l cht no ? (b) Cho bitcc nhm chc tham gia vo qu trnh to vng ny.

(a) Andoz nh nht c kh nng ny l tetroz, vi bn nguyn t cacbon v mtnguyn t oxi s to c mt vng nm cnh. (b) Vng c hnh thnh bi phn ngkt hp gia nhm -CHO v nhm -OH cui mch.

60. Vit cu to v ch r hai ng phn anome ca D-threo.

Cu to v ng phn anome ca D-threo :

C

C OH

H2C

C

H

OHH

HO

H

-D-threofuranoz

O

C

C OH

CH2OH

C

H

OH

HO

H

C

C OH

H2C

C

H

HHO

HO

H O

-D-threofuranozD-threoz

61. v -D-glucoz c gc quay cc ring khc nhau.Khi ho tan dng ny hoc dngkia vo nc gc quay cc ca chng u b thay i cho n mt gi tr khng i gingnhau. (a) Cho bit thut ng c s dng cho trng hp bin i ny. (b) Gii thch s

bin i . (a) S chuyn i gc quay ny c gi l s nghch chuyn. (b) Dng v -D-

glucoz u to c cn bng vi dng mch h cha nhm -CHO v do vy chngc th to cn bng vi nhau :

-D-glucoz dng andehit -D-glucoz

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Khi mi anomebt u thit lp cn bng th gc quay cc ring ca chng cng btu thay i v ch gi nguyn khi cn bng c thit lp. Cc baz nh NaOH cth lm xc tc cho qu trnh ny nhanh t n trng thi cn bng.

62. Tnh thnh phn % cc anome thu c ti cn bng hnh thnh do s nghch chuyn caglucoz, bit gi tr gc quay cc ring ca v -D-glucoz ln lt bng +112o,+19o v gi tr gc quay cc ca hn hp ti cn bng l +52,7o.

t a v b ln lt l phn mol ca v -D-glucoz, ta c :a + b = 1

112a + 19b = 52,7

Gii h phng trnh ny thu c a 100% = 36,2% v b 100% = 63,8%

63. Nhng pht biu sau l ng hay sai : (a) Glucoz l andoz duy nht c kh nng

nghch chuyn. (b) Xetoz cng c kh nng nghch chuyn. (c) Cc glucosit nghchchuyn c. (d) C quan h gia kh nng nghch chuyn v kh nng kh thuc thFehling ca mt ng.

(a) Sai, s nghch chuyn xy ra vi mi ng c tn ti dng semiaxetan. (b) ng,xetoz tn ti nh mt semiaxetan v cng c cc anome. (c) Sai, nhm OH caanome tham gia qu trnh ete ha v do vy cn bng vi dng cha nhm cacbonylt do b ph v. (d) ng, qu trnh kh thuc th Fehling v s nghch chuyn u dos c mt ca nhm cacbonyl t do.

64. T cc d kin sau cho bit D-glucoz l furanoz hay pyranoz ? Gi tn cc sn phm

trung gian ca qu trnh ny :D-glucoz HCl/MeOH A NaOH/SOMe 42 B ddHCl C 3H N O axit 2,3-dimetoxisucxinic + axit2,3,4-trimetoxiglutaric.

Phn ng xy ra vi cc cu to furanoz v pyranoz :

C

C OMe

C

CH2OMe

OH

C

H

OMe

C

H

MeO

H

H

dng andehit

C

C OMe

C

CH2OMe

C

H

OMe

C

H

MeO

H

H

pyranoz

O

OHH OH

C

C OMe

COOH

C

H

OMe

COOH

H

MeO

H

axit 2,3,4-trimetoxiglutaric

+ CO2

C

COOH

C

H

OMe

COOH

H

MeO

axit 2,3-dimetoxisucxinic

+ MeOCH2COOH

HNO

3

HNO3

(a

)

(b)

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C

C OH

C

CH2OMe

OMe

C

H

OMe

C

H

MeO

H

H

dng andehit

C

C

C

CH2OMe

OMe

C

H

OMe

C

H

MeO

H

H

furanoz

O

OHH OH

C OMe

COOH

H

axit dimetoxiglyxeric

+

HNO 3

HNO3

(c)

(d)

C

COOH

C

H

OMe

COOH

H

MeO

axit 2,3-dimetoxisucxinic

+ MeOCH2COOH

COOH

C OMe

COOH

H

CH2OMe

axit metoximalonic Hnh23-6

Cc sn phm trung gian l :

A = metyl D-glucosit (ete ha nhm OH-anome)

B = metyl tetra-O-metyl-glucosit (ete ha 4 nhm OH khc)

C = tetra-O-metyl-glucoz (OMe-anome b thy phn)

Cu to cc sn phm sinh ra do s oxi ha mnh lit l :

HOOCCH(OMe)CH(OMe)COOH + HOOCCH(OMe)CH(OMe)CH(OMe)COOH

Cc nhm -OH trn nguyn t cacbon tham gia vo qu trnh hnh thnh vngsemiaxetan th khng b metyl ha. i vi vng nm cnhfuranozth l nhm

-OH C1 v C4, cn i vi vng su cnhpyranozth l nhm -OH C1 v C5. Soxi ha mnh lit trong giai on cui cng chuyn nhm C-OH-anome thnh nhm-COOH v gy ra s ct mch lin kt bn cnh nguyn t C lin kt vi nhm -OHbc 2. Hnh 23-6 minh ha sn phm c th c sinh ra t mi loi vng, cc hng tosn phm (a) v (b) l t vng su cnhpyranoz, cn (c) v (d) l t vng nm cnhfuranoz. V hng (a) v (b) to ra cc sn phm tng ng vi cc sn phm thuc t thc nghim nn glucoz phi c cu to vngpyranoz.

65. T dy chuyn ha di y, lm th no xc nh mt metyl glucosit c vng

pyranozhayfuranoz: ng 4

H IO.1

2B r.2

d c hd u n g

+OH.3

3

u tin HIO4 gy phn ct lin kt C-C lin kt vi cc nhm -OH lin tip, sau dung dch Br2 oxi ha nhm -CHO thnh nhm -COOH, v cui cng axit c sdng thy phn cu ni axetan nh c th phn mnh hp cht ban u. Hnh 23-7 cho bit cc sn phm sinh ra t mi loi vng :

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C

C OH

C

CH2OH

C

H

OH

C

H

HO

H

H

Metyl-D-glucopyranosit

OCH3

O

H

C O

C

CH2OH

C O

C

H

H

H

OCH3

O

H

COOHH

COOH

C

CH2OH

OH

COOH

C

H

OH

+

Axit D-glyxeric

2HIO4 1. dd Br2

2. H3O+

C

C

C

CH2OH

OH

C

H

OH

C

H

HO

H

H

Metyl-D-glucofuranosit

OCH3

O

H

C

C

C O

C

H

H

H

OCH3

O

H

COOH

C

COOH

OH

COOH

C

H

OH

+

Axit hidroximalonic

CH O

O

H2C O

+

- CO2COOH

C

H

OHH

2HIO4 1. dd Br2

2. H3O+

Nh vy nu so snh cc sn phm thc nghim thu c vi hai hng chuyn hatrn s xc nh c loi vng.

66. (a) V cng thc Haworth cho -D-glucopyranoz. (b) Cng thc ca dng c khc im no ?

Cng thc Haworth c dng vng phng t vung gc vi mt phng giy. Xoay C6

trong cng thc Fischer (A) ra phi sau mt phng giy, quay lin kt C 4-C5 sao chonhm C5-OH n gn nhm -CH=O to vng (B). Vi cch thc hin ny th nhm-CH2OH cui mch s pha trn i vi tt c cc ng-D. Trong loi vng nynguyn t O lun xa ngi quan st v nguyn t C-anome pha bn phi, cc

nhm th bn tri trong cng thc Fischer pha trn mt phng vng v nhm th bnphi s pha di. Xem hnh 23-8. (b) Trong ng phn anome dng , nhm -OH-anome pha trn.

1CHO

OHH

HHO

OHH

OHH6CH2OH

HHC

CH2OH

OH

H

OHH

OH

H

OH

O

HHC

OH

OH

H

OHH

OH

CH2OH

H

O

H O

OH

H

OHH

OH

CH2OH

HH

OH

A B C

67. V cu dng gh cho -D-glucopyranoz

C hai cu dng gh chuyn ha ln nhau, y chng ta chn cu dng bn hn ngvi nhm th ln nht (nhm -CH2OH) v tr bin. Xem hnh 23-9

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Hnh 23-9 :

HOO

H

H

HO

H

H

OHHOH

OH

HOO

H

H

HO

H

H

OHHOH

OH

Hoc n gin hn :

68. Ti sao -D-glucopyranoz chim hm lng ln trong t nhin ?

Cc nhm th trong cu dng gh u v tr bin nn cu dng ny bn.69. V cu dng gh bn v km bn cho (a) -D-manopyranoz (xem bi 23-47) v (b) -

L-glucopyranoz

(a) Xem hnh 23-10(a), ng vi cu dng bn hn, nhm -CH 2OH v ba nm -OH khc v tr bin. (b) Xem hnh 23-10(b).

(a)

HOO

H

H

HO

OH

H

HHOH

OH

(bn hn)

O

OH

OH

H

H

H

OHH

H

OH

OH

(km bn hn)

(b)

O

H

H

H

HO

HO

OHOH

H

H

OH

(bn hn)

H O

OH

OH

H

OH

OH

HHH

OH

H

(km bn hn)

Hnh 23-10

70. (a) V cu dng gh bn v km bn cho -D-idopyranoz (ng phn epime ca D-glucoz - xem bi 23.45). (b) Gii thch s la chn ca bn.

(a) Xem hnh 23-11. (b) D nhm -CH2OH v tr trc, nhng li c bn nhm -OH v tr bin nn cu dng (a) bn vng hn.

(a)

O

H

H

H

HO

HO

OHOH

H

H

OH

(bn hn) (b)

HO

OH

OH

H

OH

OH

HHH

OH

(kmbn hn)

Hnh 23-11

71. (a) Trong fructoz nguyn t cacbon no l C-anome ? (b) Vit cng thc chiu Fischercho cc ng phn anome ca (i) D-fructofuranoz v (ii) D-fructopyranoz.

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(a) C2

(b) (i) D-fructofuranoz :

HHOOHH

OH6CH2OH

-D-fructofuranoz

OH

1CH2OH

HHOOHH

OH6CH2OH

HO

1CH2OH

O

HHOOHH

OHH6CH2OH

1CH2OH

-D-fructofuranoz dng mch h

(ii) D-fructopyranoz :

HHO

OHH

OHH6CH2O

-D-fructopyranoz

OH

1CH2OH

HHO

OHH

OHH6CH2O

HO

1CH2OH

-D-fructopyranoz

72. V cng thc chiu Haworth cho cc ng phn anome ca D-fructofuranoz.

Cng thc chiu Haworth cc ng phn anome ca D-fructofuranoz :O 1CH2OH

OH

OH

HOH2C6

HO

O OH

CH2OH

OH

HOH2C

HO

-D-fructofuranoz -D-fructofuranoz Hnh 23-12

73. Tng t bi 23-66, ch ra cch hnh thnh cng thc chiu Haworth cho cc ng phnanome ca D-fructopyranoz.

Nhm OH-anome quay xung di v v tr cis so vi C5-OH to to ra dng ,Nhm OH-anome quay ln trn v v tr trans so vi C5-OH to to ra dng :

O 1CH2OH

OH

OH

HO

CH2

OH

HOHO HO

OH

O

CH2OH O OH

1CH2OH

OH

HOHO

-D-fructopyranoz -D-fructopyranoz Hnh23-13

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74. (a) V cu dng gh bn cho a-D-fructopyranoz. (b) (b) Cng thc ca dng c khc im no ?

(a) Xem hnh 23-14. (b) OH v 1CH2OH trn C2 o v tr.

HO

O

H

OH

H

OH

OH

HH

1CH2OH

Hnh 23-14

Disaccarit v Polisaccarit

75. (a) Cho bit c im cu to c trng ca cc disaccarit. (b) Trong cng thc cadisaccarit trt t cc monosaccarit c quy nh nh th no ?

(a) Disaccarit l mt glycosit, trong nhm OH-anome ca monosaccarit th nht tocu ni theo kiu axetan vi -OH ca monosaccarit th hai (monosaccarit th hai nyc gi l aglycon). (b) Aglycon l monosaccarit pha cui bn phi.

76. (a) Biu din cu to di dng cng thc Fischer, cng thc dng gh v (b) gi tn theodanh php IUPAC cho mantoz, mt disaccarit c aglycon l mt phn t glucoz (A),aglycon s dng C4-OH ca n lin kt vi -OH ca nt phn t glucoz th hai(B). (c) c im cu trc no ca mantoz l khng xc nh ?

(a) Xem hnh 23-15. (b) 4-O-( -Dglucopyranoz)- -D-glucopyranoz. (c) Cu hnhC-anome ca aglycon l khng xc nh.

C

C OH

C

CH2OH

C

H

OH

C

H

HO

H

H

O

OH

C

C O

C

CH2OH

C

H

OH

C

H

HO

H

H

O

HHO

SemiaxetanAxetan

HO

O

H

HOOH

OH

OO

HOOH

OH

OH

Hnh 23-15(A)(B)

77. Cho bit sn phm ca phn ng gia mantoz v (a) dung dch HCl, (b) enzim mantazav (c) enzim emulsin.

(a) v (b) Mantoz b thy phn to ra hai ng lng glucoz, mantaza ch xc tccho qu trnh thy phn cu ni -glycosit. (c) Khng phn ng, emulsin ch xc tccho qu trnh thy phn cu ni -glycosit

78. Mantoz phn ng nh th no vi (a) dung dch Fehling, (b) dung dch NaOH, (c) dungdch brom v (d) lng d PhNHNH2.

V aglycon ca mantoz c nhm OH-anome t do, cc anome tn ti cn bng vidng mch h cha nhm andehit, nn mantoz phn ng c vi tt c cc cht nutrn, lin kt glycosit khng b nh hng. (a) v (c) C1-anome ca aglycon b oxi hathnh -COOH. (b) Xy ra s nghch chuyn. (d) Hnh thnh nn mt osazon.

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79. Khi oxi ha mantoz bng dung dch brom thu c axit cacboxilic (C), axit ny phnng vi (MeO)2SO2/NaOH to ra mt dn xut octametyl (D).Thy phn (D) trong HClthu c 2,3,4,6-tetra-O-metyl-D-glucopyranoz (E) v axit 2,3,5,6-tetra-O-metyl-D-gluconic (F). S dng cc d liu trn v kt qu ca cc bi 23.77, 23.78 lp lun xcnh cu to mantoz v cc cht C, D, E, F.

T kt qu ca cc bi 23.77 v 23.78 ta bit rng mantoz l mt -glycosit, aglyconca n c cha OH-anome t do (lp th cha xc nh). Axit (C) hnh thnh do s oxiha C1 ca aglycon (A) thnh nhm -COOH, kt qu l vng semiaxetan ca n b phv. Qu trnh metyl ha trc khi thy phn thnh monosaccarit xc nh cc nhm-OH trn cc nguyn t cacbon khng tham gia vo bt kh lin kt no. Nguyn t Otrn C5 ca E khng b metyl ha cho thy rng n tham gia vo s hnh thnh vngpyranoz. V tt c cc nhm -OH ca E, tr OH-anome v -OH to vng, u b metylha nn ta c th suy ra rng E sinh ra t B v F sinh ra t A. C4-OH ca F khng bmetyl ha cho thy rng -OH ny tham gia hnh thnh cu ni ete. Xem hnh 23-16.

HO

O

H

HOOH

OH

OOH

COOHHOOH

OHMantoz dd Br2 Me2SO4NaOH

MeOO

H

MeOOMe

OMe

OOMe

COOHMeOOMe

OMe

H3O+ MeO

O

H

MeO

OMe

OHMeO

HOOMe

COOHMeO

OMe

MeO+Hnh23-16

80. Xenlobioz, mt disaccarit thu c t xenluloz, c cu cc cu t ging nh mantoznhng b thy phn bi enzim emulsin. Cho bit cu trc (dng gh) ca xenlobioz.

Khc vi mantoz, xenlobioz l mt -glucosit. Xem hnh 23-17

HOO

HOOH

O

OH

1

O4

OH

OH

OH

HO

AB Hnh23-1

81. (a) Lp lun xc nh cu to ca lactoz, mt disacacrit c trong sa, bit : (1) Thyphn trong emulsin to ra D-glucoz v D-galactoz, (2) l mt ng kh c khnng nghch chuyn. (3) Khi thy phn osazon ca n thu c D-glucosazon v D-galactoz, (4) Oxi ha nh nhng, sau metyl ha ri cui cng thy phn to cc snphm tng t nh sn phm thu c t mantoz. (b) Vit cng thc cu to osazon calactoz.

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(a) T (1) suy ra lactoz l mt -glucosit cu thnh t D-glucoz v D-galactoz. (2)cho bit lactoz c nhm OH-anome t do. (3) cho bit cu t glucoz l aglycon don to c osazon v galactoz l mt -galactosit. (4) cho bit c hai cu t u dng pyranoz v lin kt vi nhau qua C4-OH ca cu t glucoz. Xem hnh 23-18(a).(b) Xem hnh 23-18(b).

O

OH

HOOH

O

OH

1

O4

OH

OH

OH

HO

(B) D-galactoz Hnh23-17(A) D-glucoz

NNHPh

HHO

4 OH

OHH

6CH2OH

B

NNHPhH

Lactoz osazo

82. M t qu trnh ri lon tiu ha gy ra do s d ng lactoz.

Lactoz khng th hp th trc tip vo mu, m cn c thy phn trc thnh cccu t i tc dng ca men lactaza c trong rut. Lng lactoz khng b thy phncng vi mt t lactaza s chy qua ng rut gy au bng v cc triu trng ngrut khc. S d nglactoz thng gp nhng ngi ln tui.

83. (a) Bng cch no chng ta bit rng mantoz, xenlobioz v lactoz khng cha cu tL-monosaccarit? (b) Cc ng L c xut hin trong t nhin hay khng ?

(a) Thy phn disaccarit thnh monosaccarit sau kim tra gc quay cc ring, ccmonosaccarit thu c s xy ra s nghch chuyn, nhng cc ng phn anome caglucoz v galactoz u quay phi. y l c im ca cc ng phn quang hckhng i quang thuc dy D ca cc monosaccarit ny. (b) C nhng t. Khc vi

aminoaxit trong t nhin thng thuc dy L, cc dng tn ti trong t nhin ch yuthuc dy D.

84. T cc d kin sau y hy xc nh cu trc ca saccaroz (mt loi ng n ph binc tch t cy ma v c ci ng) : (i) n khng kh c thuc th Fehling vkhng nghch chuyn. (ii) Khi thy phn bng men mantaza hoc emulsin u to snphm l D-glucoz v D-fructoz. (iii) Metyl ha sau thy phn to ra 2,3,4,6-tetra-O-metyl-D-glucopyranoz v tetrametyl D-fructoz. (b) Phn no ca cu trc khng chac xc nh ? (c) Gi tn saccaroz theo danh php IUPAC.

(a) T (i) suy ra saccaroz khng c OH-anome t do. (ii) cho bit OH-anome ca mt

cu t l (thy phn c trong mantaza) v OH-anome ca cu t kia l (thyphn c trong emulsin). (iii) cho bit cu t glucoz l mt pyranosit do C5 khng bmetyl ha. Hnh 23-19 l mt v d cho cu to xc nh c. (b) Loi vng ca cut fructoz (trong thc t n l mt furanosit) v lin kt glycosit (trong thc tes linkt ny hnh thnh gia -glucoz v -fructoz. (c) V cha xc inh cu t ngvai tr glycon nn c th c hai trng hp sau : -D-glucopyranosyl- -D-fructofuranosit hoc -D-fructofuranosyl- -D-glucopyranosit.

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HOO

HO

O

OH

OH

Hnh23-1

O

C6H2OH

OH

HOH2C1

HO

85. (a) nh ngha ng nghch chuyn. (b) Tnh gc quay cc ring ca ng nghchchuyn, bit rng D-glucoz c [ ]D = 52,7o v D-fructoz c [ ]D = -92,4o.

(a) ng nghch chuyn l hn hp ng phn t ca D-glucoz v D-fructoz thuc do s thy phn saccaroz. (b) Gc quay cc ring bng trung bnh cng gcquay cc ca mi cu t :

[ ]D = [ ] 9,19)4,92(7,522

1=++

86. Cho bit sn phm to thnh khi thy phn saccaroz c metyl ha hon ton.

Xem hnh 23-20. (Cu hnh C-anome khng xc nh nn cc lin kt bu din cbng ng son).

H3COO

H3CO

O

OCH3

Hnh23-20

O

C6H2OCH3

OCH3

CH3OC1

H3COCH3O

H3O+ H3CO

O

H3CO

OH

OCH3

O

C6H2OCH3

OCH3

CH3OC1

H3COCH3O

H

HO+

2,3,4,6-tetra-O-metyl-D-glucopyranoz

1,3,4,6-tetra-O-metyl-D-glucofuranoz

87. Lp lun xc nh cu trc ca mt disaccarit (A) c cng thc phn t C10H18O9, bitrng khi oxi ha bi brom, sau metyl ha v cui cng x l vi men mantaza th thuc sn phm l 2,3,4-tri-O-metyl-D-xyloz v axit 2,3-di-O-metyl-L-arabinoic.

Do thy phn c di tc dng ca mantaza nn A l mt -disacccarit. Cu t baxit ha v c t nhm -OCH3 hn l aglycon, trong trng hp ny chnh l L-arabinoz. V C5-OH ca c hai cu t u khng b metyl ha nn cc pentoz nyu l cc pyranoz. C4-OH ca L-arabinoz khng b metyl ha, iu ny cho thy n tham gia to cu ni ete vi OH- -anome ca xyloz. Cu to y ca A nhtrong hnh 23-21.

HOO

HOOH

Hnh23-2

OOH

OH

OOH

4-O-(-D-xylopyranosyl)-L-arabinopyranosit

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88. Lp lun xc nh cu trc ca gentiobioz C12H22O11, bit rng gentiobioz c kh nngnghch chuyn v khi thy phn bi men emulsin to D-glucoz. Thy phn sn phmmetyl ha ca gentiobioz sinh ra 2,3,4,6-tetra-O-metyl-D-glucopyranoz v 2,3,4-tri-O-metyl-D-glucopyranoz.

Gentiobioz l mt -disacccarit (thy phn c bi emulsin) cu thnh t hai cu tglucoz. Glucoz-aglycon c cha nhm OH-anome t do (c kh nng nghchchuyn). C hai cu t u l pyranoz v nhm C 5-OH khng b metyl ha. Nhm C6-OH ca aglycon khng b metyl ha cho bit v tr to cu ni ete. Cu to y cagentiobioz nh trong hnh 23-22 ( y gi thit rng aglycon l -glucoz) :

HOO

HOOH

Hnh23-26-O-(-D-glucopyranosyl)--D-glucopyranoz

HOO

HOOH

CH2

O OH

OH

89. Lp lun xc nh cu trc ca (a) trehaloz khng kh C12H22O11, bit khi thy phnbng mantaza thu c D-glucoz, (b) isotrehaloz c cu to tng t trehaloz, chkhc l c th thy phn bi mantaza hoc emulsin. Thy phn c hai cht ny sau khi metyl ha u to sn phm duy nht 2,3,4,6-tetra-O-metyl-D-glucopyranoz.

(a) Xem hnh 23-23 (a). Trehaloz gm hai cu t D-glucoz, cc cu t ny u sdng OH- -anome to lin kt. V C5-OH khng b metyl ha nn mi cu t dul mt pyranosit. (b) Xem hnh 23-23. Trong isotrehaloz, cu ni ete gia hai cu tc hnh thnh bi OH- -anome ca cu t th nht vi OH- -anome ca cu tth hai.

HOO

HOOH

O

-D-glucopyranosyl--D-glucopyranosit

Trehaloz(a)

OH

OHO

OH

OH

HO

HOO

HOOH

O

-D-glucopyranosyl--D-glucopyranosit

Isotrehaloz(a)

OH

O

OHOH

OH

HO

90. Cho bit tn gi hai polisacacrit c trong thc vt cu thnh t mt loi cu t duy nht lglucoz.

Tinh bt v xenluloz.

91. Khi thy phn khng hon ton amyloz, mt thnh phn ca tinh bt c kh nng hatan trong nc, to ra mantoz v D-glucoz. Metyl ha, sau thy phn hon ton thsn phm chnh l 2,3,6-tri-O-metyl-D-glucopyranoz. Cho bit cu to ca amyloz.

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Amyloz cha cc phn t mantoz lin kt vi nhau bng lin kt -1,4-glucosit tora mt helix (cu to xon c).

92. Metyl ha sau thy phn amyloz thy c xut hin 2,3,4,6-tetra-O-metyl-D-glucopyranoz chim hm lng t 0,2 n 0,4%. Gii thch ngun gc pht sinh sn

phm ny. Sn phm ny sinh ra t phn t glucoz cn cha C4-OH t do u mi mch

polime.

93. Khi metyl ha v thy phn amylopectin, mt thnh phn ca tinh bt c kh nng hatan trong nc, to sn phm chnh tng t amyloz. Tuy nhin cn c mt phn ccsn phm khc nh 2,3,4,6-tetra-O-metyl-D-glucopyranoz (chim hm lng khong5%) v khong 5% 2,3-di-O-metyl-D-glucopyranoz. Lp lun xc nh cu trc caamylopectin.

Qu trnh metyl ha v thy phn to sn phm tng t nh amyloz cho thy hu htcc lin kt trong amylopectin l tng t ging nh trong amyloz. S xut hin casn phm 2,3-di-O-metyl-D-glucopyranoz cho thy s khc bit u tin l trongamylopectin ngoi cc lin kt -1,4-glucosit to thnh mch chnh cn c cc lin kt -1,6-glucosit to thnh mch nhnh. Sn phm 2,3,4,6-tetra-O-metyl-D-glucopyranoz xut hin vi hm lng % ln hn cho thy rng mch polime caamylopectin ngn hn so vi amyloz.

94. (a) Glycogen l g v glycogen khc tinh bt im no ? (b) Xenluloz l g v cu trcca xenluloz khc g so vi tinh bt ?

(a) Glycogen l mt loi polisacacrit d tr trong c th ng vt, trong khi tinh bt lmt loi polisacacrit d tr trong c th thc vt. Glycogen c cu to tng t nhamylopectin nhng s lng mch nhnh ln hn. (b) Xenluloz, loi hp cht hu cc hm lng ln nht trong t nhin, l thnh phn chnh ca g v cu to thc vt;cotton (si bng) gn nh l xenluloz nguyn cht. Ging vi tinh bt, cu t caxenluloz cng l glucoz nhng khc vi tinh bt, lin kt trong xenluloz l -1,4-glucosit, mch ca xenluloz c rt t nhnh v khi lng phn t xenluloz ln hnkhi lng phn t tinh bt.

95. (a) Xc nh khi lng phn t trung bnh ca tinh bt, bit rng 25oC dung dch ncca tinh bt c p sut thm thu = 5,0.10-3atm . (b) Vi mu th ny trung bnh c

khong bao nhiu cu t glucoz trong mt phn t tinh bt. (a) T RTCM= vi CM l nng mol mol, R l hng s kh (0,082 L.atm.mol -1.K-

1) v T l nhit tuyt i, ta c :

14

11

3

M L.mol10.0,2)K298).(K.mol.atm.L082,0(

atm10.0,5

RTC

==

=

14

14

1

mol.g10.0,5L.mol10.0,2

L.g0,10M

==

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H

CHO

OHH

OH

HOH2C

H

COOH

OHH

OH

COOH

OH

CHO

HH

OH

CH2OH

OH

COOH

HH

OH

COOH

[O] [O]

- Sn phm kh l 1,2,3,4- butantetrol. Dng threo to mt ng phn i quang c tnhquang hot, cn dng erythro to mt ng phn meso khng c tnh quang hot.

H

CHO

OHH

OH

HOH2C

H

CH2OH

OHH

OH

CH2OH

OH

CHO

HH

OH

CH2OH

OH

CH2OH

HH

OH

CH2OH

[H] [H]

d) Cho bit cc cht trung gian v sn phm to thnh khi cho D-Threo tc dng viPhNHNH2.

H

CHO

OH

OHH

CH2OH

H

C=NNHPh

OH

OHH

CH2OH

H- C=NNHPh

C=O

OHH

CH2OH

H- C=NNHPh

C=NNHPb

OHH

CH2OH

H-

PhNHNH2+PhNHNH2+PhNHNH2

-PhNH2,-NH3

e)Khi D-erythro tham gia phn ng ny th sn phm l g ? Gii thch sn phm thu c.Gii: D-erythro cng to mt ozazon ging nh trn . Cu hnh C2 trong ng ban u khngquan trng do n b oxiha thnh >C=O, mt xeton ging nhau t c 2 loi ng trn.

f) Vit 2 sn phm l ng phn hnh thnh trong phn ng gia D-Threo v NaCN/HCN.Tisao 2 ng phn ny c to thnh vi hm lng khng bng nhau ?2. Cho bit cc sn phm to thnh khi cho HIO4 tc dng vi HO-CH2-(CHOH)4-CHO (A) vHO-CH2-(CHOH)3CO-C H (B). Suy ra ng dng ca phn ng ny.

99.Mt isaccarit A khng c tnh kh. Khi thu phn trong mi trng axit,

A cho sn phm duy nht l pentoz B. Cng c th thu phn A nh enzim -glicoziazasong khng dng c -glicoziaza. T B c th to ra D-glucoz bngcch cho tc dng vi HCN ri thu phn (xc tc axit) v kh.a) Vit cng thc Fis v gi tn B theo danh php h thng.b) Vit s cc phn ng chuyn ho B thnh D-glucoz.c) Vit cng thc cu trc ca A dng vng 6 cnh phng.d) khng nh cu trc vng 6 cnh ca A, ngi ta cho A tc dng vi

CH3Br trong mi trng baz ri thu phn (xc tc H+). Dng cngthc cu trc, vit s cc phn ng.

100 .Monosaccarit A (t l glicoz A) c tn l (2S,3R , 4S , 5R)2,3,4,5,6

pentahiroxihexanal. Khi un nng ti 1000C, A b tch nc sinh ra sn phm B c tn l1,6anhiroglicopiranoz. Dglucoz khng tham gia phn ng ny. T A c th nhn ccc sn phm E (C5H10O5) v G (C5H8O7) theo s phn ng:

A

Br2

H2OC

CaCO3 HNO3 GEDH2O2

1. Vit cng thc Fis ca A v B.

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2. A tn ti 4 dng gh (D-glicopiranoz). Vit cng thc ca cc dng v cho bit dngno bn hn c?3. Dng cng thc cu dng biu din phn ng chuyn ho A thnh B. V saoDglucoz khng tham gia phn ng tch nc nh A?4. Vit cng thc cu trc ca E v G. Hy cho bit chng c tnh quanghot hay khng?1. T cloaxetanehit v BrMgC CMgBr vi cc cht v c cn thit tng hp c cht (A),(B) c cng thc sau. Hy vit s cc phng trnh phn ng v ghi r iu kin (nu c).

CH2OH CH2OH

H OH H OH(A) H OH (B HO H

H OH HO HH OH H OH

CH2OH CH2OH

2. Galactal (G) tc dng vi metanol nh xc tc OH

HCl sinh ra 2 sn phm mch vng A1 v A2 c H CH2OH

cng cng thc phn t C7H14O5. (G) H H

a) Hy trnh by c ch phn ng v cng thc HO

cu trc ca A1 v A2. H H

b) Cho A1 hoc A2 tc dng vi dung dch axit trong nc sinh ra mt hn hp sn phm lunlun chuyn ho ln nhau theo cn bng. Dng cng thc lp th m t cn bng . 1. Vitphng trnh phn ng iu ch D-fructoz t D-glucoz, bit rng

D-glucozazon khi tc dng vi benzanehit to thnh ozon ca D-glucoz(HOCH2(CHOH)3COCHO).

2. Chitin (tch t v tm, cua...) c coi nh l dn xut ca xenluloz, trong cc nhm hiroxyl cc nguyn t C2 c thay th bng cc nhm axetylamino ( -NH-CO-CH3 ).

a) Vit cng thc cu to mt on mch ca phn t chitin.b) Gi tn mt mt xch ca chitin.

c) Vit phng trnh phn ng xy ra khi un nng chitin vi dung dch HCl c (d),un nng chitin vi dung dch NaOH c (d).

101. ( thi HSG quc gia, Vit Nam - 1998)1. A l disaccarit kh c AgNO3 trong dung dch NH3, gm hai ng phn c kh nng lm

quay mt phng nh sng phn cc trong nhng iu kin thng nht biu th bng [ ] D25

l + 92,6o v +34o. Dung dch ca mi ng phn ny t bin i v [ ] D25 cho cho ti khi

cng t gi tr n nh l + 52o. Thy phn A (nh xc tc axit) sinh ra B v C:

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H

CHO

OH

HO

OHH

OHH

CH2OH

H

(B)

H

CHO

OH

HO

HHO

OHH

CH2OH

H

(C)

Cho A tc dng vi lng d CH3I trong mi trng baz thu c sn phm D khng ctnh kh. un nng D vi dung dch axit long thu c dn xut 2,3,6-tri-O-metyl ca Bv dn xut 2,3,4,6-tetra-O-metyl ca C .(a) Vit cng thc cu trc (dng vng 6 cnh phng) cho B, C, A, D; bit trong phn t A

c lin kt -1,4-glucosit. Gii thch v vit cc phng trnh phn ng.(b) V sao dung dch mi ng phn ca A t bin i v [ ] D

25 v cui cng u t gi

tr 52o ? Tnh thnh phn phn trm cc cht trong dung dch gi tr [ ] D25 = 52o v

vit cng thc cu trc cc cht thnh phn .

2. Metyl ha hon ton cc nhm OH ca 3,24 gam amilopectin bng cch cho tc dng viCH3I trong mi trng baz ri un thy phn hon ton (xc tc axit) th thu c1,66.10-3 mol 2,3,4,6-tetra-O-metylglucoz v 1,66.10-3 mol 2,3-di-O-metylglucoz, phncn li l 2,3,6-tri-O-metylglucoz,(a) Vit cng thc cu trc (dng vng 6 cnh phng) ca 3 sn phm trn v cho bit xut

x ca chng.(b) Cho bit t l % cc gc glucoz ch c nhnh ca phn t amilopectin.(c) Tnh s mol 2,3,6-tri-O-metyl glucoz sinh ra trong th nghim trn.

1. (a) Cng thc ca B, C :

H

CHO

OH

HO

OHH

OHH

CH2OH

H

(B)

O

OHOH

OH

CH2OH

H

OH

H

CHO

OH

HO

HHO

OHH

CH2OH

H

(C)

O

OH

OH

CH2OH

H

OH

OH1

2

1 1

1

2

Dn xut 2,3,6-tri-O-metyl ca B v dn xut 2,3,4,6-tetra-O-metyl ca C c cng thc :

O

OHOCH3

OCH3

CH2OCH3

H

OH

O

OCH3

OCH3

CH2OCH3

H

OH

CH3O1

2

3

4 5

6

1

2

3

4

5

6

2,3,6-tri-O-metyl ca B dn xut 2,3,4,6-tetra-O-metyl ca C

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iu ny cho thy lin kt -1,4-glucosit (theo gi thit) hnh thnh gia nhm C1-OHca cht C vi C4-OH ca cht B v v A l disaccarit kh c AgNO 3 trong dung dchNH3 nn cn nhm C1--OH-semiaxetal ca B. Cng thc ca A l :

O

OH

OH

CH2OH

H

OH

O

OH

OH

CH2OH

OH1

2

3

4 5

6

12

3

4

5

6

O

(A)

D khng c tnh kh, nh vy OH- semiaxetal ca A cng b metyl ha. Cng thc caD l :

O

OCH3

OCH3

CH2OCH3

H

OCH3

O

OCH3

OCH3

CH2OCH3CH3O

1

2

3

4 5

6

12

3

4

5

6

O

(D)

(b) Cc ng phn anome ca A c th chuyn ha ln nhau thng qua cu trc h. Do vytrong dung dch, mi ng phn ca A t bin i v hn hp cn bng ca hai ng phnng vi mt gi tr [ ] D

25 duy nht bng 52o. Gi hm lng % dng th nht l x%, ta c:

52100

x-100).34(

100

x).6,92( +=+++ x = 30,7

Vy ng phn c kh nng lm quay mt phng nh sng phn cc trong nhng iu kinthng nht biu th bng [ ] D

25 l + 92,6o v +34o ln lt c gi tr bng 30,7% v 69,3%.Cng thc ca cc ng phn ny l :

O

OH

OH

CH2OHO

OH

OH

CH2OH

OH1

2

3

4 5

6

12

3

4

5

6

O

O

OH

OH

CH2OHO

OH

OH

CH2OH

OH

2

3

4 5

6

12

3

4

5

6

OOH

OH

2. (a) Cng thc cu trc (dng vng 6 cnh phng) :

O

OHOCH3

OCH3

CH2OH

HOH

1

2

3

4 5

6

2,3-di-O-metylglucoz(Y )

O

CH3OOCH3

OCH3

CH2OCH3

HOH

1

2

3

4 5

6

2,3,4,6-tetra-O-metylglucoz(X)

O

OHOCH3

OCH3

CH2OCH3

HOH

1

2

3

4 5

6

2,3,6-tri-O-metylglucoz(Z)2,3,4,6-tetra-O-metylglucoz sinh ra t u mch phn t amilopectin; 2,3-di-O-metylglucoz sinh ra t ch c nhnh ca phn t amilopectin; 2,3,6-tri-O-metylglucozsinh ra t trong mch v cui mch phn t amilopectin.

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(b) S mol glucoz tham gia to amilopectin = 310.20162

24,3 =

% cc gc glucoz ch c nhnh ca phn t amilopectin = %3,8%100.10.20

10.66,13

3=

(c) S mol 2,3,6-tri-O-metyl glucoz sinh ra = 20.10-3 - 2.1,66.10-3 = 16,68.10-3.

102. ( thi HSG quc gia, Vit Nam - 1999)Tmt loi thc vt ngi ta tch ra c hp cht (A) c cng thc phn t C 18H32O16. Thyphn hon ton (A) thu c glucoz (B), fructoz (C) v galactoz (D) :1. Vit cng thc cu trc dng vng phng 5 v 6 cnh ca galactoz.2. Hidro ha glucoz, fructoz v galactoz thu c cc poliancol. Vit cng thc cu trc

ca cc poliancol tng ng vi (B) , (C) v (D).3. Thy phn khng hon ton A nh enzim -galactoridaza (enzim xc tc cho phn ng

thy phn cc -galactosit) thu c galactoz v saccozoz. Metyl ha hon ton (A)nh hn hp CH3I v Ag2O, sau thy phn sn phm metyl ha, thu c 2,3,4,6-tetra-O-metylgalactoz (E) v 2,3,4-tri-O-metylglucoz (G) v 1,3,4,6-tetra-O-metylfructoz

(H). Vit cng thc cu trc ca (E), (G), (H) v (A).1. Cng thc cu trc dng vng phng 5 v 6 cnh ca galactoz :

H

CHO

OH

HO

HHO

OHH

CH2OH

HO

OH

OH

CH2OH

H

OH

OH

1

1

2

3

4

5

6

OH

OHO

OH

H

CH2OH

HHO1

2

3

4

6

5

2. Hidro ha glucoz to sn phm c s nguyn t C bt i khng i, hidro ha galactoz

to ng phn meso, hidro ha fructoz to hn hp cc ng phn dia.V d :

H

CHO

OH

HO

OHH

OHH

CH2OH

H [H]

H

CH2OH

OH

HO

OHH

OHH

CH2OH

H

H

CHO

OH

HO

HHO

OHH

CH2OH

H

H

CH2OH

OH

HO

HHO

OHH

CH2OH

H

CHO

O

HO

OHH

OHH

CH2OH

H

H

CH2OH

OH

HO

OHH

OHH

CH2OH

H

HO

CH2OH

H

HO

OHH

OHH

CH2OH

H+

[H] [H]

D-fructozD-glucoz D-galactoz

3. Thy phn khng hon ton A nh enzim -galactoridaza thu c galactoz v

saccozoz, nh vy A c cu thnh t -galactoz, -glucoz, -fructoz, cng thcca 2,3,4,6-tetra-O-metylgalactoz (E), 2,3,4-tri-O-metylglucoz (G) v 1,3,4,6-tetra-O-metylfructoz (H) l :

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O

OCH3

OCH3

CH2OH

12

3

4 5

6

CH2OCH3

CH3O

OCH3

O H

CH2OCH3

1

23

4

5

6

O

OCH3

OCH3

CH2OCH3

2

3

4

5

6

CH3O

OH

H

CH3O OH

H

(E) (G) (H)

Cc sn phm thy phn ny cho thy cu to ca A l :

O

OH

OH

CH2

12

3

4 5

6

CH2OH

HO

OH

O H

CH2OH

O

H1

23

4

5

6

O

OH

OH

CH2OH

OH

2

3

4

5

6

O

OH

H

103. ( thi HSG quc gia, Vit Nam - 2000)X l mt disaccarit khng kh c AgNO3 trong dung dch NH3. Khi thy phn X sinh ra snphm duy nht l M (D-andoz, c cng thc vng dng ). M ch khc D-riboz cu hnhnguyn t C2.

Mcm-O-t r i-2 , 3x u d n

+H/OH N a O H/IC HH C l/O HC H 233

QNM1. Xc nh cng thc ca M, N, Q v X (dng vng phng).2. Hy vit s cc phn ng xy ra.

a. T cng thc dn xut 2,3,4-tri-O-metyl ca M suy ngc s ra cng thc ca Q,

N, M t suy ra cng thc ca X :

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CH3OCHO

HOCH3HOCH3H

CH2OH

O

OHOCH3

CH3OCH3O

O

OCH3OCH3

CH3OCH3O

dn xut 2,3,4-tri-O-metyl ca M

(Q)

H2O/H+

O

OCH3OH

OHHO

(N)

CH3I/baz

O

OHOH

OHOH

(M)

H2O/xt

CH3OH/HClO

OH

OHOH

(X)

O OH

OH

OHO

b. S phn ng : ...

104. ( thi HSG quc gia, Vit Nam - 2001)Melexitoz (C18H36O16) l ng khng kh, c trong mt ong. Khi thy phn hon ton 1 molmelexitoz bng axit s nhn c 2 mol D-glucoz v 1 mol D-fructoz. Khi thy phnkhng hon ton s nhn c D-glucoz v disaccarit turanoz. Khi thy phn nh enzimmantaza s to thnh D-glucoz v D-fructoz, cn khi thy phn nh enzim khc s nhnc saccaroz. Metyl ha 1mol melexitoz ri thy phn s nhn c 1 mol 1,4,6-tri-O-

metyl-D-fructoz v 2 mol 2,3,4,6-tetra-O-metyl-D-glucoz.1. Hy vit cng thc cu trc ca melexitoz. Vit cng thc cu trc v gi tn h thng

ca turanoz.2. Hy ch ra rng vic khng hnh thnh fomandehit trong sn phm oxi ha bng HIO4

chng t c cu trc furanoz hoc pyranoz i vi mt xch fructoz v pyranoz hocheptanoz (vng 7 cnh) i vi mt xch glucoz.

3. Cn bao nhiu mol HIO4 phn hy hai mt xch glucoz c cu trc heptanoz v snhn c bao nhiu mol axit fomic ?

1. T cc d kin u bi suy ra melexitoz khng cn -OH semiaxetan, l trisaccarit c

cu thnh t 2 dn v D-glucoz v 1 n v D-fructoz, trong 1 n v D-glucoz linkt vi D-fructoz to thnh disaccarit turanoz, n v D-glucoz th hai cng lin ktvi D-fructoz to thnh disaccarit saccaroz. Thu phn 1 mol sn phm metyl homelexitoz thu c:

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CH2OCH3

CH2OCH3OHOH

CH3OO O

OH

OCH3

OCH3

CH2OCH31

23

CH3O

1

2

T suy ra n v D-fructoz dng furanorit, 2 n v D-glucoz u dngpiranorit; 2 n v D-glucoz u to ra lin kt glicorit vi C2 v C3 ca D-fructofuranozit.

Cu trc :

HO

O

HO

O

OH

H

HO

CH2OH

H

OHO

HO

O

HO OOH

H

HO

HOH2C1

2 3

1

1

HO CH2OH

H

OHO

HO

O

HO OOH

H

HO

HOH2C1

2 3

1

Melexitoz (C18H36O16) 3-O-(-D-glucopiranozyl)-D-fructofuranoz (Turanoz)

Ho?c :

HO

O

HO

O

OH

H

HO

HO

O

HO OOH

H

HO

1

1

Melexitoz (C18H36O16) 3-O-(-D-glucopiranozyl)-D-fructofuranoz (Turanoz)

OHOH2C

HO CH2OH

1

2

3

HO

O

HO

O

OH

H

HO

1

OHOH2C

HO CH2OH

1

2

3HO

2. Cu trc furanoz hoc piranoz i vi mt xch fructoz v piranoz hoc heptanoz(vng 7 cnh) i vi mt xch glucoz do khng c nhm 1,2-diol kiu -CHOH-CH2OH

nn khng hnh thnh fomanehit trong sn phm oxi ho bng HIO4 :

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HO

CH2OH

HO

OHH

OHHCH2

OH

CH2OH

HO

OHH

HCH2OH

OH

piranoz furanoz

Fructoz

H

HC

OH

H

OHH

OHHCH2

OOH

H

CH

OH

H

OHH

HCH2OH

OOH

heptanoz

Glucoz

piranoz

HO

HO HO

3. Cn 6 mol HIO4 phn hu hai mt xch glucoz c cu trc heptanoz v s nhn c4 mol axit fomic :

H

HC

OH

H

OHH

OHHCH2

OOH

+6HIO4

HC

CHO

CHOCH2

O +4HCOOH +6HIO3 +2H2O2 2

HO HO

105. ( thi HSG quc gia, Vit Nam - 2002)Oxi ho 150 mg amiloz bi NaIO4 thu c 0,0045 mmol axit fomic.

(a) Tnh s lng trung bnh cc gc glucoz trong phn t amiloz; bitrng khi oxi ho 1 mol amiloz bng NaIO4, s gc glucoz u mch tora 1 mol axit fomic, s gc glucoz cui mch to ra 2 mol axit fomic.

(b) Vit s cc phng trnh phn ng xy ra.Vit s cc phng trnh phn ng chuyn D-glucoz thnh L-guloz c

cng thc bn.

1. (a) S lng trung bnh cc gc glucoz trong phn t amiloz :

(C6H10O5)n 4H I O 3HCOOH

)m m(0 0 1 5,0=3

0 0 4 5,0=n

3

1=n H C O O Ha m i l o z

)v C(1 0 0 0 0 0=0 0 1 5,01 5 0=M a m il o z

617162

100000=n

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H

CH2OH

HO

H OH

HO H

HO H

CHO


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(b) Phng trnh phn ng:

O

OHOH

OH

CH2OH

O

OHOH

OH

CH2OH

O

O

OH

OH

CH2OH

O

n-2

OHCOHC

OCH2OH

CHO

CHOOCH HC

OCH2OH

O

n-2O O

+ (n+4) HIO4

- 3 HCOOHHCHO(n+4) NaIO3

2. S chuyn ha :

H

CHO

OHHHO

OHH

OHH

CH2OH

+ HNO3H

COOH

OHHHO

OHH

OHH

COOH

- H2O

H

CO

OHHHO

H

OHH

COOH

O + Na(Hg) H

CH2OH

OHHHO

OHH

OHH

COOH

- H2O

H

CH2OH

OH

HOHH

OHH

CO

O

+ Na(Hg)

H

CH2OH

OH

HHOOHH

OHH

CHO

pH = 7

106. ( thi HSG quc gia, Vit Nam - 1997)

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Mannoz (monosaccarit) HOCH2-CHOH)4-CH=O l ng phn ca glucoz. dng vng sucnh mannoz ch khc glucoz ch nhm OH nguyn t C2 nm cng pha vi OH nguyn t C3. Oxi ha mannoz bng dung dch HNO3 100oC thu c sn phm Y cha41,38%C, 3,45%H v 55,17%O. Y b thy phn c trong mi trng axit cng nh baz to raaxit polihidroxidicacboxilic hoc mui tng ng. Xc nh cng thc cu to ca Y, bit MY =

174vC.

t cng thc tng qut ca Y l CxHyOz

Tao c : 6100.12

174.38,41x == , 6

100

174.45,3y == , 6

100.16

174.17,55z ==

Cng thc phn t ca Y l C6H6O6Axit nitric oxi ha nhm -CH2OH v -CHO trong phn t mannoz thnh hai nhm -COOH.Nu sn phm cui l HOOC-(CHOH)4-CHO (C6H10O8) th khng ph hp vi cng thcphn t ca Y (C6H6O6). Mt khc theo gi thit Y b thy phn trong mi trng axit cngnh baz, vy Y phi l este ni phn t (lacton) hai ln este. ng vi cu trc bn (vng 5

hoc su cnh) th cu to ca Y s l :

HO

CO

HH

H

OHHCO

1

6

O

O

hay

O

C

O

OO

OH

OH

1

23

45

6

CO

H

HHO

OHHH

CO

1

6

O

O hay

O

O

O

O OH

HO1

2

3

4

5

6

107. ( thi HSG quc gia, Vit Nam - 2001)1. Vit phng trnh phn ng iu ch D-fructoz t D-glucoz, bit rng D-glucozazon khi

tc dng vi benzandehit to thnh oson ca D-glucoz (HOCH2(CHOH)3COCHO).2. Chitin (tch t v tm, cua...) c coi nh l dn xut ca xenluloz, trong cc nhm

hidroxyl cc nguyn t C2 c thay th bng cc nhm axetylamino ( -NH-CO-CH3 ).c) Vit cng thc cu to mt on mch ca phn t chitin.

d) Gi tn mt mt xch ca chitin.e) Vit phng trnh phn ng xy ra khi un nng chitin vi dung dch HCl c

(d), un nng chitin vi dung dch NaOH c (d).

1. Phng trnh phn ng iu ch D-fructoz t D-glucoz :

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HCHO

OHHHOOHHOHH

CH2OH

+2C6H5NHNH2

CHN-NH-C6H5HHOOHHOHH

CH2OH

N-NH-C6H5

+2H2O

+2C6H5NHNH2

CHOHHOOHHOHH

CH2OH

O

+2C6H5CHO

CHN-NH-C6H5HHOOHHOHH

CH2OH

N-NH-C6H5

H+

[H]

CH

O

HHO

OHHOHH

CH2OH

O CH2OH

OHHO

OHHOHH

CH2OH

2. (a) Cng thc ca chitin

O

NHCOCH3

OH

CH2OHO

NHCOCH3

OH

CH2OH

O OO

HO

NHCOCH3

OH

OO

OO

H

OH

NHCOCH3

hay

(b) N- axetyl-D-glucozamin(tn gi ca chitin : poly N-acetyl-D-glucosamine, -(1,4)-2-Acetamido-2-deoxy-D-

glucose)(c) Sn phm phn ng khi tc dng vi dung dch HCl c (d), dung dch NaOH c(d) :

O OH

NH3Cl

OH

CH2OH

OH

O

NH2

OH

CH2OHO

NH2

OH

CH2OH

O O

108. (Bi tp chun b IChO, Canada - 1997)D-andotetroz A khi phn ng vi axit nitric cho hp cht khng hot ng quang hc. Cngandotetroz ny khi phn ng vi HCN, tip theo vi dung dch nc Ba(OH) 2 cho hai axitandonic epime B v C. Cc axit andonic ny nm trong cn bng vi cc -andolacton D vE tng ng ca chng. X l hn hp ny vi Na - Hg v nc pH 3-5 thu c cc cht Fv G tng ng. Oxi ha F bng axit nitric thu c axit andaric khng hot ng quang hcH, trong khi thc hin phn ng ny vi E thu c axit andaric hot ng quang hc I.

Cho bit cu trc cc cht t A n I

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Ch D-andotetroz dng erythro mi cho sn phm khng hot ng quang hc khi b oxi habi axit nitric :

CHO

OHH

OHH

CH2OH

+ HNO3

COOH

OHH

OHH

COOH(A)

S l A bng HCN, tip theo vi dung dch nc Ba(OH)2 cho hai axit andonic epime B v C :

CHO

OHH

OHH

CH2OH

1.HCN OHH

OHH

CH2OH(A)

2. Ba(OH)2

OHH

COOH

OHH

OHH

CH2OH

HHO

COOH

+

(B) (C)

Cc -lacton D v E tng ng l :

OHH

OHH

CH2OH

OHH

COOH

(B)

OHH

H

CH2OH

OHH

CO

(D)

O OHH

OHH

CH2OH

HHO

COOH

(C)

OHH

H

CH2OH

HHO

CO

(E)

O

X l hn hp ny vi Na - Hg v nc pH 3-5 thu c cc cht F v G. Oxi ha bng axitnitric thu c axit andaric khng hot ng quang hc H v hot ng quang hc I :

OHH

OHH

CH2

OH

OHH

CHO

(F)

(D) OHH

OHH

CH2OH

HHO

CHO

(G)

(E)Na(Hg)

pH=3-5OHH

OHH

COOH

OHH

COOH

(H)

HNO3OHH

OHH

COOH

HHO

COOH

(I)

Na(Hg)

pH=3-5

HNO3

109. (Bi tp chun b IChO, Canada - 1997) -D-(+) mannopiranoz l epime ca -D-(+) glucopiranoz

a. Hy vit cu trc dng gh bn vng nht ca n.b. Cho bit sn phm phn ng ca - D - (+) mannopiranoz vi cc cht :

(a) Cu2+ + (m pH > 7) (g) 5HIO4(b) Br 2, H2O (pH = 6) (h) (CH3CO)2O d trong piridin(c) HNO3 (i) 3 mol phenylhidrazin, H+

(d) CH3OH , HCl khan (j) 1. Br 2/H2O 2. Fe (III) sunfat , H2O2

(e) Sn phm (d) + (CH3)2SO4, NaOH (k) 1. HCN 2. Ba(OH)2(f) 1. NaBH4 2.H2O 3. H3O+ 4. Na-Hg, H2O, pH=3-5

1. Cu trc dng gh bn vng nht ca -D-(+) mannopiranoz :

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O

HO

OH

HO

H

OH

HO

2. Sn phm phn ng ca - D - (+) mannopiranoz :

HOCOO_

H(a)

HOCOOH

H

(b)

HOCOOH

HHHOOHHOHH

COOH

(c)+ Cu2O

(d) (e)HO

CH2OH

HHHOOHHOHH

CH2OH

(f)

OCH3

O

CH3O

OCH3

OCH3

H

CH3O

CH3O

(g)

OH

O

H

(h)

NNHC6H5HHOOHH

OHHCH2OH

(i)

5 ng lng

H

O

H

1 ng lng

AcOCHO

HHAcOOAcH

OAcHCH2OAc

NNHC6H5H

CHOHHOOHHOHH

COOH

(j)HO H

HHOOHHOHH

COOH

(k) HHOCHO

HO HHHOOHHOHH

COOH

OHHCHO

+

110. (Bi tp chun b IChO, Thi Lan - 1999)1. Dng cng thc Haworth ngh mt hay nhiu cu to vng vi ha lp th c th c cho

D-tagaloz.

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CH2OH

C

HHO

HHO

OHH

CH2OH

O

(D)-tagaloz

2. Hai sn phm c cng cng thc C6H10O6 thu c khi D-arabinoz tc dng vi NaCN/H+

ri thy phn trong mi trng axit. Vit cu to km theo ha lp th c th c ca haihp cht v cho bit chng to thnh nh th no ?

CHO

HHO

OHH

OHH

CH2OH

1. NaCN/H+

2. H3O+/ to

? + ?

(D)-arabinoz

1. Cu to vng vi ha lp th c th c cho D-tagaloz :CH2OH

OH (CH2OH)HOH HO

O O

CH2OH (OH)

OHOH

HO

CH2OH (OH) OH (CH2OH)

2. Phn ng ca D-arabinoz :

CHOHHOOHHOHH

CH2OH

NaCN/H+

(D)-arabinoz

HHO

OHHOHH

CH2OH

HHOCN

HHOOHHOHH

CH2OH

OHHCN

+H3O

+/ to

HHO

OHHOHH

CH2OH

HHOCOOH

HHOOHHOHH

CH2OH

OHHCOOH

+

-H2O

-H2O

OOOHOH

OH

CH2OH

OO

OH

OH

OH

CH2OH

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111. (Bi tp chun b IChO, Canada - 1997)D-idoz c cu hnh khc D-glucoz C-2, C-3 v C-4. cn bng, D-idoz gm 75% dng

piranoz v 25% dng furanoz.1. Hy vit c hai cu dng xyclohexan ca cc ng phn dng vng , ca D-

idopiranoz. ng phn no bn vng nht ? V sao ?2. Qua s ng phn ha Lobry de Bruyn Abberda van Ekenstein, D-idoz c th chuyn

thnh 2-xetoz (D-socboz). Hy v dng furanoz ca D-socboz3. Khi un nng D-idoz mt nc thun nghch v tn ti ch yu di dng 1,6-dihidro-D-

idopiranoz. Hy cho bit phn ng ny thch hp vi dng ng phn no ? Vit cngthc hp cht ny. Cho bit ti sao phn ng ny khng xy ra vi glucoz ?

a. Hai cu dng gh ca D-idoz l :

O

OH

OH

OHOH

OH

O

OH

OH

OHOH

OH

OHO

HO

OH

OHOH

O

HOHO

OH

OH

OH

vng

vng

cu dng bn hn vc nhiu nhm thbin hn

cu dng bn hn vc nhiu nhm thbin hn

HO

CHO

H

OHH

HHO

OHH

CH2OH

b. Cu to ca D-socbofuranoz :

CH2OH

OH (CH2OH)H

OH

OH

OCH2OH (OH)

CHO

O

OHH

HHO

OHH

CH2OH

c. Phn ng dehidrat ha ng vng ni phn t thun li khi nhm OH trn C1 vnhm -CH2OH u v tr trc. Nh vy vi D-idoz phn ng thun li vidng , cn glucoz khng c c phn ng ny :

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OHO

HO

OH

OH

OH

OHO

HO

OH

O

- H2O

112. (Bi tp chun b IChO, Canada - 1997)Disaccarit A b thy phn bi axit long to hn hp gm D-glucoz v D-galactoz. Hp chtA l mt ng kh v b oxi ha bi nc Br2 to axit B, axit ny c metyl ha bng(CH3)2SO4/NaOH to thnh hp cht octa-O-metyl ha. Thy phn hp cht ny thu c axittetra-O-metylgluconic C v tetra-O-metylgalactoz D. Hp cht C b oxi ha bi axit nitric to

thnh axit tetra-O-metylglucaric. Cht A b thy phn bi -galactosidaza tch t hnh nhn.Cho bit cu trc ca A, B, C, D.

O

HO

O

OHH

OHOH

O

HO

HO

OHH

HO

(A)

O

HO

O

OHH

OHOH

OH

COOHHOOH

HO

(B)

Br2

1. metyl ha

HCH3O

OCH3H

OCH3H

CH2OH

OCH3H

COOH

HH3CO

HCH3O

OCH3H

CH2OH

OCH3H

CHO

+2. thy phn

HNO3 HCH3O

OCH3H

OCH3H

COOH

OCH3H

COOH

(C)

(D)

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113. ( thi olympic quc gia ba nc min BalTic)Khi thy phn tinh bt bng axit th thng ch to thnh sn phm c v ngt (glucoz,mantoz...).Khi thy phn tinh bt trong cng nghip (30-40% huyn ph tinh bt trongdung dch HCl long, nhit 130-140oC) mt vi hp cht dng c to thnh. Ngita ngh rng cht ng ng X ny c to thnh do phn ng thy phn thun

nghch. X c tch ra v tinh ch. xc nh cu to ca n ngi ta tin hnh ccth nghim sau :

1. Thy phn trong dung dch axit : Ch c glucoz c tch ra trong phn ng ny.2. Th andehit : 25mg X c ha tan trong 25cm3 dung dch kalihexaxyanoferat(III)

K3[Fe(CN)6] 0,01M. Sau thm 5cm3 dung dch KOH 0,1M v a hn hp ln 100oC

trong khong 15 pht. Lng d K3[Fe(CN)6] c xc nh bng phng phpchun iot. Thm mt lng d KI v hn hp c axit ha bng CH 3COOH.10,5cm3 Na2S2O30,01M c dng chun.

3. Metyl ha v oxi ha : X c metyl ha bng mt lng d metyliodua, c mtbc(I)oxit. Sau sn phm metyl ha c un nng vi HNO3 30%. Hai axit ctch ra t hn hp l: axit 2,3,4-trimetoxi-5-hidroxiadipic HOOC-CH(OH)-

[CH(CCH3)]3-COOH v axit 2,3,4,6-tetrametoxi-5-hidroxicaproic CH3OCH2-CH(OH)-[CH(OCH3)]3COOH.

a. Xc nh cu to ca X.b. Vit phng trnh phn ng ca cc th nghim nhn bit X.

114. ( thi olympic quc gia H Lan)D-glucoz, cht ng c nhiu trong thin nhin, l mt trong nhiu ng phn lp th ca2,3,4,5,6-pentahidroxihexanal cng thc phn t l C6H12O6. Khi ha tan trong nc n tn ti nhiu dng vng v mt dng h. Hnh bn l hnh chiu Haworth ca mt trong nhngdng vng. Khi c mt baz, D-glucoz c th chuyn thnh nhng cht ng khc.1. Hy cho bit hnh chiu Fisher ca hai cacbonhidrat, trong cu to m to thnh u tin

trong phn ng ca dung dch D-glucoz trong nc vi baz.D-glucoz b kh bi NaBH4 thnh D-gluxitol.2. Khi nhm c trng no trong D-glucoz b chuyn ha ?Cho D-glucoz tc dng vi peiodat d3. Cho bit cng thc cu to ca nhng sn phm to thnh trong phn ng ny.

115. (Bi tp chun b IChO, Canada - 1997)Disaccarit A khng phn ng vi thuc th Benedict v khng nghch chuyn. A b thy phn

bi -glucoridaza, khng b thy phn bi -glucosidaza. Metyl ha A, tip theo thy phnthu c 2 ng lng mol 2,3,4,6-tetra-O-metyl-D-glucoz.1. Cho bit cu trc ca A.2. Cho bit bao nhiu mol axit peiodic s phn ng vi A.3. Cho bit bao nhiu mol metanal v bao nhiu mol axit metanoic c hnh thnh trong

phn ng ca A vi axit peiodic.

116: Phn ng oxiha ct mch gluxit bi HIO4 c nhiu mc ch khc nhau.

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(cc nhm-CHOH- v -CHO H-COOH ; -CH2OH H-CHO ; >C=O CO2)

a) D Arabinoz l ng phn cu hnh C2 ca D Riboz. xc nh cu to ca n

ngi ta thc hin cc phn ng sau :

DArabinoz

3CH OHHCl

A

4HIO

B

3

2 2

1) H2) Br /

OH O

+

HOOCCO

OH

OHOH

OH

O

b) Nu phng php phn bit D glucoz vi D fructoz

Oxiha bng HIO4 :

H

CHO

OH

HHO

OHH

OHH

CH2OH

H OH

HHO

OHH

H

CH2OH

H OH

O+ 5 HIO4

- 5 HIO3

HCHO + 5 H-COOH

(D- Glucoz)

O

HHO

OHH

OHH

CH2OH

HO

OHH

H

CH2

O

+ 4 HIO4

- 4 HIO3

2 HCHO + 3 H-COOH

(D-Fructoz)

CH2OH CH2OH

HO

OH

H

+ CO2

Cho hi sn phm sc qua dung dch nc vi ta nhn c D Fructoz

CO2 + Ca(OH)2CaCO3+ H2O OH + HOCH2-COOH

Hi D Arabinoz c cu to vng 5 cnh hay 6 cnh ? V cu to

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Nu l vng 5 cnh th :

OH

CHO

H

OHH

OHH

CH2OH

OH H

OHH

H

CH2OH

O

OH

OH H

OHH

H

CH2OH

O

OCH3

CH3OH

HCl

HIO4

H

CH2OH

O

OCH3

CHO

CHO

Br2

H2O

COOH

COOH

COOH

CH

CH2OH

OH

(D-Arabinoz)

Kt qu tri gi thit, vy D Arabinoz c cu to vng 6 cnh

OH

CHO

H

OHH

OHH

CH2OH

OH H

OHH

H

CH2

O

OH

CH3OH

HCl

HIO4O

CHO

CHO

Br2

H3O

+

COOH

COOH

COOH

CH2

CH2OH(D-Arabinoz)

OH

OH H

OHH

H

CH2

O

OCH3

OH

OCH3

CH2

Cu to vng ca D Arabinoz l : hay

O

OHOH

OH

HO

117: a) X l mt isaccarit khng kh c AgNO3 trong dung dch amoniac. Khi thu phn X

sinh ra sn phm duy nht l M (D-anoz , c ng thc vng dng ). M ch khcD-riboz cu hnh nguyn t C2 .

M 3CH OH

HCl N 3

CH INaOH

Q 3H O+

dn xut 2,3,4-tri-O-metyl ca M

Xc nh cng thc ca M , N , Q v X ( dng vng phng ) .

T cng thc dn xut 2,3,4-tri-O-metylca Msuy ngc s ra cng thc ca Q ,NvM,

t suy raX. (X khng c tnh kh phn t khng c nhm OH semiaxetal )

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CHO

H

OCH3H

OCH3H

CH2OH

(D-Riboz)

H

CHO

OH

OHH

OHH

CH2OH

CH3OO

CH3O

OHCH3O

CH3O

(Dn xut 2,3,4-tri-O-metyl ca M )

O

O

1 1

2

2

3

3

44

5

5O OH

OH

OH

OH

OH

HO

H3O+ O

1

23

4

5

OH

OH

HO OH

(M)(X)

O

OH

OH

HO OCH3

CH3OH

HCl

(N)CH3I

NaOH

O

CH3O OCH3

(Q)CH3O

CH3O

b) A l mt isaccarit kh c AgNO3 trong dd NH3, thu phn A (nh cht xc tc axit) sinh

ra D glucoz v D galactoz (ng phn cu hnh C4 ca D glucoz). Cho A tc dng

vi mt lng d CH3I trong mi trng baz thu c sn phm B khng c tnh kh. un

nng B vi dung dch axit long thu c dn xut 2,3,6-tri-O-metyl ca D glucoz v dn

xut 2,3,4,6-tetra-O-metyl ca D galactoz. Vit cng thc cu trc (dng vng 6 cnh

phng) ca B, C, A, D; bit rng trong phn t A c lin kt - 1,4 - glicozit.

Cu to vng phng ca D glucoz v D galactoz

O

OH

OH

OH

H O

CH2OH

OH

OH

OH

H O

CH2OH

A c tnh khphn t c nhm OH semiaxetal

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O O

O OHOH

OHOH

OH

HO

(B)(A)

CH3I

NaOH

CH2OHCH2OH

O O

O OCH3

OCH3

OCH3OCH3

OCH3

CH3O

CH2OCH3CH2OCH3

11

22 33

44

55

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