Helvetica chimica acta

From Colchicine and Some of Its Derivatives to 1, 2, 3, 9, 10??Pentamethoxybenzo [a] heptalenes

P Kouroupis, HJ Hansen

Index: Kouroupis, Pavlos; Hansen, Hans-Jurgen Helvetica Chimica Acta, 1995 , vol. 78, p. 1247 - 1277

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Citation Number: 11

Abstract

Abstract A two-step synthesis of 4-methylcolchicine (13), starting from colchicine (2), has been developed (Scheme 5). In three steps, 4-ethylcolchicine (28) is also accessible from 2 (Scheme 8). Colchicine (2) and its derivatives 13 and 28 have been transformed into the benzo [a] heptalene derivatives 9, 18, and 34, respectively, by Hofmann degradation of the corresponding deacetylcolchiceine 3, 19, and 29, respectively, followed by methylation of ...