摘要:
                                The mechanism of an unusual decarboxylative cyclization from 5-metlioxy-1-(2-carboxyphenyl)-1,4-dihydro-4-oxopyridine-2-carboxylic acid (diacid) to 3-methoxypyrido[1,2-et]indole-2, 10-dione (ketone) has been investigated. C-13-labeling has demonstrated that the carbonyl carbon of the ketone arises exclusively from the anthranilic acid carboxyl of the diacid. A zwitterionic mechanism has been proposed. (C) 2004 Elsevier Ltd. All rights reserved.