Aqueous One-Pot Synthesis of Pyrazoles, Pyrimidines and Isoxazoles
Promoted by Microwave Irradiation

Abstract

Microwave irradiation promotes the conversion of enaminoketones formed in situ into a variety of heterocycles by reaction with the appropriate bidentate nucleophile. The advantages of the method over previous approaches are short reaction times and facile purification by precipitation of the products in aqueous media. Moreover the convenient one-pot procedure makes these syntheses particularly suitable for library production. Organic reactions in aqueous media have become of great interest as water is not only more environmentally friendly, but also because organic reactions in water often display unique reactivity and selectivity.

Key words

bidentate nucleophiles - tandem addition-elimination/cyclodehydration - enaminoketones - microwave irradiation

References

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10

Reaction of phenylhydrazine with pentane-2,4-dione (29%), 3-oxo-3-phenylpropionic acid ethyl ester (20%), 1-methanesulfonylpropan-2-one (32%), 2-methanesulfonyl-1-phenylethanone (72%), N,N-diethyl-3-oxo-3-phenylpropionamide (37%), and 3-oxo-3-phenylpropionitrile (10%) gave the yields shown in the parenthesis.