Unexpected behavior of enaminones: Interesting new routes to 1,6-naphthyridines, 2-oxopyrrolidines and pyrano[4,3,2-de][1,6]naphthyridines

Abstract

Reaction of enaminones 1a-d with 2-Aminoprop-1-ene-1,1,3-tricarbonitrile (2) in the presence of AcOH/NH4OAc afforded 7-Amino-5-oxo-5,6-dihydro-1,6- naphthyridine- 8-carbonitrile derivatives 9a-d. On the other hand, 2-Aminopyrano[4,3,2-de] [1,6]naphthyridine-3-carbonitriles 20a-c,e were the only obtained products from the reactions of 1a-d with 2 in the presence of AcOH/NaOAc, while 1d afforded [3,5-bis-(4- chloro-benzoyl)-phenyl]-(4-chloro- phenyl)-methanone 21 under the same condition. The reaction of 2 with diethyl acetylenedicarboxylate in the presence of AcOH/NH4OAc afforded (4-cyano-5-dicyanomethylene-2-oxo-2,5-dihydro-1H-pyrrol-3-yl)-Acetic acid ethyl ester 15B. © 2013 by the authors.