Synthesis of some 7-phenylpyrrolo[1,2-a]pyrimidine derivatives. III.

2-Amino-4-phenylpyrrolyl-3-carbonitrile (I) was reacted with ethyl formylacetate sodium salt affording 1,4-dihydro-4-oxo-7-phenylpyrolo[1,2-a]pyrimidin-8-carbonitrile (II), which was alkylated with EtI to give (III), which in turn was hydrolyzed to (IV). Treatment of both (III) and (IV) with 99% H3PO4 at approximately 200 degrees gave 1,4-dihydro-1-ethyl-7-phenylpyrrolo-[1,2-a]pyrimidin-4-one (V) whose structure was ascertained by an unequivocal synthesis starting from (I) and diethyl ethoxymethylenmalonate. Compound (V) was prepared in order to test its pharmacological properties in comparison with 4,7-dihydro-4-ethyl-2-phenylpyrazolo[1,5-a]pyrimidin-7-one, which showed an antiinflammatory activity comparable to that of phenylbutazone and indomethacine, and which was found devoid of ulcerogenic properties.