Preparation of 5-(cyclohexylmethyl)barbituric acid derivatives by acid-catalyzed reductive cyclohexylmethylation of barbituric acids with p-hydroxy or p-methoxybenzaldehydes

A very inexpensive, simple, and high yield procedure for the preparation of valuable pharmaceutical intermediates, 5-cyclohexylmethylbarbiturates, was developed starting from either p-hydroxy or p-methoxybenzaldehyde and barbituric acid. Although the reaction sequence involves several steps, such as selecting a suitable catalyst (5% PdC in 2% percent molar ratio) and solvent (methanol–hydrochloric acid 1:1) the preparation can be carried out in only one practical step (one-pot preparation).