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Abstract Acetoacetanilide (1) has been prepared by the reaction of ethyl aceto-acetate and aniline in boiling dry xylene. Knoevenagel condensation of different aromatic aldehydes e.g. 4-isopropyl-benzaldehyde, 4-anisaldehyde and salicylaldehyde with acetoacetanilide in ethanol containing catalytic amount of piperidine furnished the corresponding α,β-unsaturated compounds 2a-c. The reaction of α,β-unsaturated compound 2a with acetoacetanilide (1) proceeds in ethanol containing DROPs of conc HCl as a catalyst to afford the corresponding N-phenyl-2-pyridinone derivative 6. The base-prompted reaction of the acidic methylene compound 7 with phenyl isothiocyanate in dry DMF at room temperature in basic medium led to the formation of the non-isolable intermediates 8 which underwent insitu heterocyclization reaction with chloroacetyl chloride to afford the corresponding bis-thiazolidin-5-one derivative 9 Insitu treatment of the non-isolable intermediates 8 with dilute HCl gave the corresponding bis-thiocarbamoyl derivatives 10a and 10b. Refluxing of 10 with chloroacetic acid afforded the corresponding bis-thiazolidin-4-one derivatives 11. Treatment of bis-thiocarbamoyl derivative 10a with diazotized sulphanilic acid affected the acetyl cleavage (Japp-Klingmann reaction type) with the formation of arylhydrazono-thiocarbamoyl derivative 12 Treatment of compound 17b with two moles of thiourea in ethanol and sodium ethoxide to give corresponding bis-1,3-thiazine derivative 25. |