Proton nuclear magnetic resonance studies on methylthiohydantoins, thiohydantoins, and hydantoins of amino acids.

Proton magnetic resonance spectra of methylthiohydantoin (3-methyl-2-thiohydantoin), thiohydantoin (2-thiohydantoin), and hydantoin derivatives of amino acids were studied in dimethyl sulfoxide-d6. Their parent amino acids could be identified by the spectra. An application to the N- and C-terminal amino acid analysis of a tripeptide was examined.