static-content.springer.com10.1007... · Web viewNational University, Busan 608-737, Republic of...
-
Upload
trinhnguyet -
Category
Documents
-
view
221 -
download
4
Transcript of static-content.springer.com10.1007... · Web viewNational University, Busan 608-737, Republic of...
Solvent-free synthesis of 4H-pyranonaphthoquinones using highly active and stable
polymer grafted layered double hydroxides (LDHs-g-POEGMA) as an efficient and
reusable heterogeneous catalyst
Suresh Kumar Krishnammagaria● Seung Min Leeb● Yeon Tae Jeonga*
aDepartment of Image Science and Engineering, Pukyong National University, Busan 608-737, Republic of Korea
bLED Convergence Engineering Department, Specialized Graduate School Science and Technology Convergence,
Pukyong National University, Busan 608-737, Republic of Korea
*Corresponding author. Tel.: +82-51-629-6411; fax: +82-51-629- 6408;
E-mail: [email protected]
Supporting Information
Table of contents
1. Experimental ………………………………………….......................................................................................S2
2. Procedure for the synthesis of poly (oligoethylene glycol methacrylate)-g-layered double hydroxides (LDHs-g-
POEGMA): …………………………………………………………………………………………………….S2
3. General procedure for the synthesis of benzo[g]chromene-5,10-diones (4a-aa) ………………………………S4
4. 1H and 13C NMR spectra’s of benzo[g]chromene-5,10-diones (4a-aa)………………………………………...S5
5. HRMS spectra’s of 4y, 4z, 4aa ……………………………………………………………………………….S32
S1
1. Experimental
Chemicals were purchased from Aldrich and Alfa Aesar Chemical Companies and used without further
purification. NMR spectra were recorded in parts per million (ppm) in CDCl 3 or DMSO-d6 on a Jeol JNM ECP 400
or Jeol JNM ECP 600 NMR instrument using TMS as internal standard. Standard abbreviations were used to denote
signal multiplicities (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet and brs = broad singnal) and the
coupling constants are given in hertz (Hz). Mass spectra were recorded on a Jeol JMS-700 mass spectrometer. All
melting points were determined using open capillaries on an Electrothermal-9100 (Japan) instrument and are
uncorrected.
2. Procedure for the synthesis of poly (oligoethylene glycol methacrylate)-g-layered double
hydroxides (LDHs-g-POEGMA)[1]
Scheme 1 Schematic presentation of synthesis of poly (oligoethylene glycol methacrylate)-g-layered double hydroxides (LDHs-g-POEGMA).
S2
Synthesis of Layered doubles hydroxides (LDHs)
LDHs were synthesized via co-precipitation method by one-pot reaction [2]. In a typical run, to an aqueous solution
containing a calcium salt (Ca(NO3)2.4H2O) and an aluminum salt (Al(NO3)3.9H2O) with the Ca/Al molar ratio of 2.0
was added dropwise to the 2M NaOH aqueous solution in a 250 mL RB flask at 65°C under vigorous stirring. The
metal concentration and pH of the solution were adjusted to 0.66 mol.L-1 and 11.5±0.1 respectively. The slurry
solution was aged for 18 h at 65 °C and then filtered, washed with deionized water several times and dried overnight
at 100 °C. Then the LDHs was obtained as white powder.
Anchoring of BTPT onto LDHs surface (LDHs-BTPT)
The mixture of 0.7g of LDHs and 20 mL of dry toluene was stirred at 100 °C. Then, 0.724 g (2 mmol) of BTPT in
10 mL dry toluene was injected into the flask under N2. The reaction was conducted for 24 h. The crude product was
filtered off and washed with DCM for three times to remove all unreacted BTPT. The final product was dried under
vacuum overnight.
Preparation of LDHs-g-POEGMA by RAFT polymerization
2 g of PEGMA, 0.3 g of LDHs-BTPT, 20 mg of AIBN, and 4 mL of dry toluene were placed in a round bottom
flask. The polymerization reaction was performed at 80 °C for 24 h under N2. The mixture was precipitated in
diethyl ether and washed three times with methanol. The product was dried under vacuum at 40 °C overnight (yield,
60%).
Reference
[1] M.V. Reddy, N.T. Kim Lien, G.C.S. Reddy, K.T. Lim, Y.T. Jeong, Green Chem. 18, 4228 (2016).
[2] Y. Kuwahara, K. Tsuji, T. Ohmichi, T. Kamegawa, K. Moria, H. Yamashit, Catal. Sci. Technol.2, 1842 (2012).
S3
3. General procedure for the synthesis of benzo[g]chromene-5,10-diones (4a-aa).
A mixture of 2-hydroxy-1,4-naphthoquinone (1, 1 mmol), 4-bromobenzaldehyde (2b 1 mmol), (E)-N-
methyl-1-(methylthio)-2-nitroethenamine (3, 1 mmol) and silica-supported tungstic acid (STA) (10 mol%) was
stirred at 80 oC under solvent-free conditions. The progress of the reaction was monitored by TLC. After completion
of the reaction, the reaction mixture was washed with ethanol. The residue dissolved in DCM, and the insoluble
STA was separated by simple filtration and washed with DCM. The solvent was evaporated under reduced pressure
and the obtained crude was recrystallized from ethanol to afford the pure yellow products (4b). The recovered
catalyst was washed with ethanol and acetone, dried and reused. The same procedure adopted for the preparation of
4a-4aa. All the products were characterized by their melting points, 1H NMR, and 13C NMR spectra. A detailed
description of spectral data for all compounds 4a-4aa is given in below.
S4
4. 1H and 13C NMR spectra’s of benzo[g]chromene-5,10-diones (4a-aa).
S5
S6
S7
S8
S9
S10
S11
S12
S13
S14
S15
S16
S17
S18
S19
S20
S21
S22
S23
S24
S25
S26
S27
S28
S29
S30
S31
5. HRMS spectra’s of 4y, 4z, 4aa
S32
S33
S34
S35
S36
S37