Synthesis of New 3-Substiuted Quinazolin-4(3H)-one Compounds

Abstract

Quinazolin-4(3H)-one is a well-known heterocyclic compound with a unique place in medicinal chemistry, and it has drawn much attention due to its diversified biological activity. In this research we report the synthesis of some quinazolin-4-one derivatives containing acetylenic moiety. The quinazolin-4(3H)-one (1) was synthesized from the reaction of anthranilic acid with formamide under the conventional or microwave irradiation conditions. The quinazolin-4(3H)-one was converted to the corresponding 3-propargyl derivative (2) by its reaction with propargyl bromide in presence of potassium carbonate as a base and acetone as a solvent. The 3-propargyl quinazolin-4(3H)-one (2) was used as a precursor to synthesize new three series of heterocyclic compounds containing quinazolin-4(3H)-one moiety. Compound (2) was treated with ethyl magnesium bromide, then the resulted solution treated immediately with carbon disulfide and sublimed sulfur to synthesize 1,2-dithiol-3-thione compound (3). The 1,2,3-triazole compounds (5a-d) were synthesized by the reaction of compound (2) with alkyl azides (4a-d) according to Click reaction. The Mannich bases (6a-i) were synthesized via Mannich reaction by reaction of the acetylenic compound (2) with secondary amines in presence of paraformaldehyde in1,4-dioxane as a solvent. All the synthesized compounds were characterized by physical and spectral measurements.