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Abstract
Abstract
Quinazolinones are classes of fused heterocycles that are of considerable interest because of the diverse range of their biological properties. A brief survey on the biological importance and the literature synthetic methods as well as the chemistry of quinazolinone derivatives is given.
This investigation describes the synthesis of 2-methyl-4-oxo-3-quinazolineacetic acid hydrazide (III) starting from anthranilic acid. The key intermediate III was reacted with cyclic anhydride namely succinic and phythalic anhydride to give succinamido and phythalimido derivatives VII a, b respectively. Also, the compound III was reacted with p-toluene sulfonyl chloride to give the sulfonamide IV.
The acid hydrazide III underwent cyclization when reacted with ethyl chloroformate in n-butanol under reflux to give 5-oxo-1,3,4-oxadiazole V which upon hydraziolysis afford the compound VI.
In addition, the compound III was reacted with carbon disulphide in ethanolic potassium hydroxide to give the potassium dithiocarbazate salt VIII which was cyclized into 1,3-thiazoles IX a-c, 1,3,4-oxadiazole X, 1,3,4-thiadiazole XII and 1,2,4-triazole XIV derivatives via the reaction with phenacyl bromides derivatives, reflux in ethanol, stirring with Conc. H2SO4 and reaction with hydrazine hydrate, respectively, furthermore, the oxadiazole X and thiadiazole XII were alkylated via the reaction with different alkyl halides in DMF containing potassium carbonate to give the thioether derivatives XI a-f and XIII a-d, respectively.
4-Amino, 1,2,4-triazole-5-thione derivative XIV, was reacted with aromatic aldehyde, phenyl isothiocynate and acetic anhydride to give azomethine derivatives XV a, b, thiourea XVI, N-acetyl derivative XVII. The triazole XIV was cyclized into the triazolothiazole derivatives XVIII, XIX and the triazolothiadiazine derivative XX