The formation of pyrimidinols from α‐acylbenzyl cyanides or α‐acylphenylacetamides

Certain α‐acylbenzyl cyanides are converted into derivatives of pyrimidinol‐4 by heating with a mixture of acetic and sulphuric acids. Scheme A could possibly explain this reaction, but is not entirely satisfactory. According to step 3, the pyrimidinol‐4 is formed by reaction of an α‐acylphenylacetamide with another amide. It is indeed possible to obtain derivatives of pyrimidinol‐4 by such a reaction (scheme B) but only for R′ = phenyl or benzyl. In some cases, a complicated mixture is obtained, due to secondary reactions. One of these, the self condensation of the α‐acyl phenylacetamide, is followed by hydrolytic cleavage of the product to a pyrimidinol‐4 or to a pyrimidine‐diol (scheme C, 2 and 3). Other secondary reactions of a simpler nature occur too. The yields of the derivatives of pyrimidinol‐4 are therefore moderate to low.