Reactions of 2-aminothiobenzamide with isocyanates: A new synthesis of 2,3-dihydroimidazo[1,2-c]quinazolin-5(6H)-one and 3,4-dihydro-2H-pyrimido[1,2-c]quinazolin-6(7H)-one

Article abstract of DOI:10.1002/jhet.5570260314

2-(2-Chloroethylureido)- and 2-(3-chloropropylureido)thiobenzamides 5a,b were prepared in good yields by treating 2-aminothiobenzamide with 2-chloroethyl and 3-chloropropyl isocyanates respectively. Subsequent treatment of compound 5a and 5b either with alkali or mineral acid led to the formation of 2,3-dihydro-imidazo[1,2-c]quinazolin-5(6H)-one 7a and 3,4-dihydro-2H-pyrimido[1,2-c]quinazolin-6(7H)-one 7b.