Synthesis of Some New Derivatives of Thiazolo[4,3-b]- and Thiazolo[2,3-b] quinazolone

The new 5H-thiazolo[4,3-b]quinazoline-3,5(1H)-diones 3, 4a–c, 5a–c and 5H-thiazolo[2,3-b]quinazoline-3,5(2H)-diones 9a–c, 11a–c were prepared by reaction of anthranilic acid with the 2-thiazolidinone-4-thione derivatives 1b, 6a–c, 7a–c and the 5-substituted 2-(alkylmercapto)-2-thiazolin-4-ones 8a-c, 10a-c , respectively.