Nucleophilic substitution and ring transformation reactions with 4-chloro-6-ethyl-3-nitropyrano[3,2-c]quinoline-2,5(6H)-dione

Abstract

4-Chloro-6-ethyl-3-nitropyrano[3,2-c]quinoline-2,5(6H)-dione (3) was obtained by nitration followed by chlorination of 4-hydroxypyranoquinoline-2,5- dione 1. Substitution reactions of compound 3 with various nucleophiles, namely: sodium azide, amines, thiophenol and malono-nitrile, led to a series of novel 4-sustituted-3-nitropyranoquinolinones. Also, nucleophilic reactions of compound 3 with hydrazine, cyanoguanidine and S-methylisothiourea, involving ring opening-ring closure of the pyranoquinolinedione nucleus, are described. © ARKAT-USA, Inc.