Heteroaromatization with 4-phenyldiazenyl-1-naphthol. Part I: Synthesis of some new naphthopyrans and naphthopyranopyrimidines

Abstract

Reaction of 4-phenyldiazenyl /or 4-( p -tolyldiazenyl)-1-naphthol (1) with various substituted α-cyanocinnamonitriles (2a-h) and ethyl α-cyanocinnamates (2i-p) afforded 2-amino-4-(aryl)-6-(phenyldiazenyl /or p -tolyldiazenyl)-4 H -naphtho[1,2- b ]pyrano-3-carbonitrile (3a-h) and ethyl 2-amino-4-(aryl)-6-(phenyldiazenyl /or p -tolyldiazenyl)-4 H -naphtho[1,2- b ]pyrano-3-carboxylate (3i-p). Reaction of compound 3a with Ac 2 O or PhCOCl and formic acid afforded N -acetylamino or N,N -dibenzoylamino and naphthopyranopyrimidine derivatives (4-8), respectively. The structures of these compounds were established on the basis of IR, UV, 1 H NMR, 13 C NMR, and MS data.