Facile and Convenient Synthesis of Novel Benzopyranopyrimidine Derivatives

Abstract

A series of new 2-alkyl thiopyrimidines (2a-e) were synthesized by reaction of the 2-mercaptopyrimidine (1) with some alkylating agents. When compound 1 reacted with activated unsaturated compounds, under Michael conditions, adducts 3a,b were obtained which on turn reacted with hydrazine to give pyridazine 4. Pyrimidine derivatives 6, 7 were synthesized by treatment of 1 with benzylidine-malononitrile in basic medium. While treatment of 1 with α,β-unsaturated acids gave the S-substituted derivatives 8 and 9 which on reacting with hydrazine afforded compounds 12 and 16, respectively. The triazole 11 was obtained by treatment of 1 with aminodithiocarbamic acid. When 2a reacted with hydrazine, primary aromatic amines or o-phenylenediamine, derivatives 18, 21 and 22 were obtained, respectively. Compound 18 in turn reacted with carbon disulphide to give dithiocarbamate 23 which on reacting with sodium chloroacetate or methyl iodide afforded the thiazole 26 and triazole 28, respectively. Moreover, condensation of 18 with aromatic aldehyde furnished the Schiff's base 29 which underwent cyclization upon treatment with chloroacetyl chloride to give azetidine 30.