A Study of the Microwave-Accelerated Condensation of Substituted Benzaldehydes with 3-Substituted Hydantoins and the Unexpected Interception of Alcohol Products

A systematic study of the effect of microwave irradiation on the condensation of substituted benzaldehydes with 3-substituted hydantoins (imidazolidine-2,4-diones) led to the isolation of benzylhydantoin alcohols as major products, as well as of benzalhydantoins. The alcohol products had characteristic HPLC retention times with respect to aldehyde and benzalhydantoin traces, and were identifiable through mass spectrometric analysis at detection as all gave molecular ions. The alcohols were isolated on preparative scale in one example and studied by two-dimensional NMR experiments such as COSY, HSQC, and HMBC. Their study in the solid state by X-ray single crystal crystallographic analysis revealed them to form as two racemic diastereoisomers that crystallized together in racemic pairs.