Synthesis of some new thiazolo [4,3-b] quinazolone and thiazolo [2,3-b] quinazolone derivatives

5H-thiazolo [4, 3-b] quinazoline-3,5[lH]-dione [III] was, synthesized via reaction of anthranilic acid with 2-thiazoli-dinone-4-thione [Ib]. 1-Arylidene and 1-arylazo derivatives of III [IVa-c] and [Va-c] were prepared by the action of anthranilic acid on 5-arylidene-4-methylmercapto-3-thiazolin-2-one [Vla-c] and 5-arylazo-2-thiazolidinone-4-thione [VIIa-c] respectively. Similarly 2-arylidene-and 2-arylazo-5H-thiazolo [2,3-b quinazoline-3,5 [2H]-diones [IXa-c] and [XIa-c] were obtained by the action of anthranilic acid on 5-arylidene-2-ethylmercapto-2-thiazolin-4-one [Vllla-c] and 5-arylazo-2-methylmercapto-2-thiazolin-4-one [Xa-c] respectively