Chloroform → 2-Methyl-4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidine-7-carbonitrile

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Reaction Steps

2-Methyl-4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidine-7-carboxamide (Example 21), 2.6 g (0.010 mol), in 30 ml of phosphorus oxychloride and 30 ml of chloroform is refluxed on a steam bath for three hours. The chloroform and excess phosphorus oxychloride are evaporated in vacuo and the residue is treated with 200 ml of ice water. The resulting precipitate is filtered to give 2.1 g of 2-methyl-4-oxo-4H-pyrido[1,2-a]-thieno[2,3-d]pyrimidine-7-carbonitrile; mp 256°-258° C. after recrystallization from glacial acetic acid.

Provenance & Evidence