A. M. El-Reedy

NEW SYNTHESIS OF IMIDAZO[1,2-a]- AND PYRIMIDO[1,2-a]PYRIMIDINES

Abstract 6-Aryl-4-oxo-2- thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitriles (1) reacted with bromomalo-nonitrile(2) to give 3-amino-7-aryl-5-oxo-5H-thiazolo[3,2-a]pyrimidine-2,6-dicarbonitriles (3a-c). The latter compounds reacted with either formic acid, formamide or ammonium thiocyanate to yield the 7-aryl-9-oxo-4-substituted-thiazolo[3,2-a:4,5-d′]dipyrimidine-8-carbonitrile derivatives (4–6), respectively. Compounds (3a-c) could be converted into 7-aryl-3-amino-1-benzyl-5-oxo-5H-imidazo[1,2-a]pyrimidine-6-carbonitriles (8) and 4-amino-8-aryl-2,6-dioxo-3-substituted-1,2-dihydro-6H-pyrim-ido[1,2-a]pyrimidn-7-carbonitriles (9) by treatment in boiling ethanol with benzylamine and cyclic secondary amines, respectively.

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.

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.

Reactions of Hydrazonoyl Halides 561: Synthesis and Reactions of 1-Bromo-2-(5-chloro-benzofuranyl)ethanedione-1-phenylhydrazone

2,3-Dihydro-1,3,4-thiadiazoles and triazolino[4,3-a]pyrimidines containing benzofuran moiety were prepared from reaction of 1-bromo-2-(5-chlorobenzofuranyl) ethanedione-1-phenylhydrazone with each of potassium thiocyanate, alkyl carbodithioates and pyrmidine-2-thiones. All newly synthesized were confirmed by elemental analysis, spectral data, and alternative route synthesis whenever possible.