Abstract
Abstract: Several 2-amino-4H-pyrano[3,2-h]quinoline-3-carbonitrile (125a-c), (129a-f) and ethyl 2-amino-4H-pyrano[3,2-h]quinoline-3-carboxylate (130a-f) derivatives were prepared from reaction of 8-hydroxyquinoline derivatives (123), (96) and (98a-c) with various ·-cyano-p-halocinnamonitriles (124a,b) or ethyl ·-cyano-p-halocinnamates (127a,b) (Schemes 1,6). Condensation of (125a) and (129a) with benzaldehyde gave the 2-benzylideneamino (131a) and (131b) respectively (Scheme 7). When 2-benzylideneamino derivatives (131a,b) were treated with hydrazine hydrate or phenyl hydrazine, ‚-enaminonitrile (125a) and (129a) were obtained rather than the pyrimidine derivatives (133a,b) (Scheme 7). Condensation of (125c) with formic acid gave pyrimido[4',5':6,5]pyrano[3,2-h]quinolin-8- one derivatives (134), while reaction of (125d) with formic acid afforded the 4H-pyrano[3,2- h]-quinoline-3-carboxylic acid (135) (Scheme 8). Treatment of (125c,d) with Ac2O under reflux for ½ h gave the 2-acetylamino derivatives (136a,b), while heating of 125c,d with Ac2O for 3 h afforded pyrimido[4',5':6,5]pyrano[3,2- h]quinolin-8-one derivatives (137a,b) respectively (Scheme 8). The reaction of 125a,c,d with formamide under reflux provided the 7H-pyrimido[4',5':6,5]pyrano-[3,2-h]quinoline derivatives (138a-c) (Scheme 8).
