A systematic study of reaction of heterocyclic enamines with electrophilic alkynes: a simple and efficient synthetic route to 2-pyridinone-fused heterocycles
The reaction of heterocyclic enamines with ethyl propiolate and diethyl acetylenedicarboxylate has been systematically studied. In contrast to their heterocyclic ketene aminal analogues, heterocyclic enamines reacted with electrophilic alkynes via the Michael addition pathway rather than the aza-ene reaction mechanism. In the presence of a strong base such as sodium ethoxide and sodium hydride, the
Reaction of 2-alkoxyimmonium methosulfates (2), and of lactam acetals (3) derived therefrom, with alpha-haloesters in presence of zinc (Reformatsky condition) yielded N-alkyl-2-(alpha-alkyl-alpha-alkoxy-carbonyl)methylene-1-azacycloalkanes (6), while reaction of 3 with alpha-haloesters without zinc gave 3-alkoxycarbonylmethyl-1-azacycloalkane-2-one (5). Similar reaction of; 2 and 3 with 4-bromomethylquinolin-2-one (4) in presence of zinc gave N-alkyl-2-[4-(2-oxoquinolyl)methylene]-1-azacycloalkanes (7), a key intermediate for the synthesis of antimalarial quinoline-4-methanols.
Matoba, Katsuhide; Fukushima, Akiko; Takahata, Hiroki, Chemical and pharmaceutical bulletin, 1982, vol. 30, # 4, p. 1300 - 1306
Methods for converting N-alkyl lactams to vinylogous urethanes and vinylogous amides via(methylthio)alkylideniminium salts
作者:Mary M. Gugelchuk、David J. Hart、Yeun-Min Tsai
DOI:10.1021/jo00331a018
日期:1981.8
Synthesis of hexahydroindol-6-ones by cycloacylation of vinylogous urethanes
作者:Joseph P. Michael、Arthur S. Howard、Ruth B. Katz、Mzwandile I. Zwane
DOI:10.1016/s0040-4039(00)61276-5
日期:1992.8
The title compounds were prepared by variations of a route in which the principal stages include conversion of N-substituted pyrrolidine-2-thiones 6 into vinylogousurethanes 10, which undergo subsequent cycloacylation. A related approach that uses a Robinson annulation was also partly successful.