Utilization of Compounds Bearing Carbonyl Group in Heterocyclic Synthesis

Abstract

The 1,3-oxazolones, the pyrazole rings and their derivatives are classes of nitrogen containing heterocyclic compounds and used extensively as important synthons in organic synthesis. Also they have widespread potential biological activities in medicinal and pesticide chemistry.

The original work of this thesis can be classified into four parts:

Part (I): Synthesis of some novel pyrazolotriazine derivatives.

The geometrical isomers of the acid hydrazide derivatives Z-(2a) & E-(2b) were previously prepared by our research group upon hydrazinolysis of 4-benzylidene-2-phenyl-1,3-oxazole-5(4H)-one 1.

Treatment of the Z-(2a) with ethyl cyanoacetate in refluxing ethanol gives 6-amino pyrazolo[1,2-a][1,2,4]-triazines-4,8-diones derivative 3. Similar treatment of the E-(2b) with ethyl cyanoacetate under the same conditions, gave E-(2b) recovered unchanged. However, its treatment with ethyl cyanoacetate in the presence of a catalytic amount of sodium ethoxide in refluxing ethanol affored the pyrazoline-3, 5-dione derivative 4 (Scheme 1).

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