2000 benzothiazole derivatives

benzothiazole derivativesR 0270

20 - 111Antitumor Benzothiazoles. Part 9. The Regiospecific Synthesis of 5-and 7-Monosubstituted and 5,6-Disubstituted 2-Arylbenzothiazoles.— Various title aminophenylbenzothiazole derivatives (III) are regiospecificallyprepared using base-mediated bromide displacement cyclization reaction ofo-bromoarylthiobenzanilides (I) as key step. Reduction of the nitro groupto amine by SnCl2 provides the expected antitumor agents (III). It is shownthat the nitro group can be reduced in the presence of the thioamide usingan indium-mediated reaction (although in moderate yield), and that theregiospecific cyclization proceeds also in the presence of the electron-donatingamine group. — (HUTCHINSON, IAN; STEVENS, MALCOLM F. G.;WESTWELL, ANDREW D.; Tetrahedron Lett. 41 (2000) 3, 425-428; CancerRes. Lab., Sch. Pharm. Sci., Univ. Nottingham, Nottingham NG7 2RD, UK;EN)

1