S. M. Hussain

REACTIONS WITH 2-METHYLTHIOPYRIMIDINES SYNTHESIS OF SOME NEW FUSED PYRIMIDINES

Abstract 4-Chloro-2-methylthio-6-phenylpyrimidine-5-carbonitrile (II) reacts with hydrazine hydrate to yield the 2,4-dihydrazino derivative (IIId). Compound IIId reacts with nitrous acid to give ditetrazolo[1,5-a:1′,5′-c]pyrimidine (VI) and with carbon disulphide to form pyrazolo[3,4-d]-s-triazolo[3,4-b]pyrimidine (VII). The reaction of II with phenylhydrazine affords directly the pyrazolo[4,3-d]-pyrimidine derivative (IV). Also, compound II reacts with anthranilic acid to form 2-methylthio-4-phenyl-6-(o-carboxyphenylamino)pyrimidine-5-carbonitrile (IIIe) which can be cyclised into 1-methylthio-10-oxo-3-phenyl-10-pyrimido[6,1-b]quinazoline-4-carbonitrile (IX) by heating with acetic anhydride.

SYNTHESIS AND REACTIONS OF 2-MERCAPTO-4-ARYL 4H-1,2,3,4,5,6-HEXAHYDRO-BENZO [h] QUINAZOLINES

Abstract 2-Mercapto-4-aryl-4H-1,2,3,4,5,6-hexahydrobenzo[b]quinazolines (2) have been synthesized. Compounds 2 reacted with chloroacetic acid, 2-bromopropanoic acid or 3-bromopropanoic acid in the presence of fused sodium acetate and acetic anhydride to give 5-aryl-5H-2,3,6,7- tetrahydrobenzo[b]thiazolo[2,3-b]quinazoline-3-ones (3), their 2-methyl derivatives (5) and 6-aryl-6H- 2,3,7,8-tetrahydrobenzo[b]-l,3-thiazine-[2,3-b]quinazoline-4-ones (6), respectively. 2-(Arylmethylene)-5-aryl-5H-2,3,6,7-tetrahydrobenzo[b]thiazolo[2,3-b]quinazoline-3-ones (4) were prepared by the reaction of compounds 2 with chloroacetic acid, and aromatic aldehydes in presence of fused sodium acetate and acetic anhydride or by the reactions of compounds 3 with aromatic aldehydes in the presence of acetic anhydride.

Halogenation of 3-hydroxy-1H-pyrido[2,1-b]benzothiazol-1-one: synthesis of two new ring systems

Abstract 3-Hydroxy-1H-pyrido[2,1-b]benzothiazol-1-one (1) reacts with sulphuryl chloride to give the 2-chloro derivative II. Bromination of I yields the 4-bromo derivative VIII. Each of II and VIII condenses with thiourea to afford 2-amino-11H-thiazolo[4′,5′:4,5]pyrido[2,1-b]benzothiazol-11-one (IV) and 2-amino-5H-thiazolo[4′,5′: 4,3]pyrido[2,1-b]benzothiazol-5-one (V), respectively. The structures of the newly synthesised compounds are proved by chemical and spectral methods.