A new method for the preparation of t-butyloxycarbonyl amino acids and p-methoxybenzyloxycarbonyl amino acids has been devised. The former was obtained in satisfactory yields from amino acids and t-butyl S-4,6-dimethylpyrimid-2-ylthiocarbonate prepared from t-butyl alcohol and (4,6-dimethylpyrimid-2-ylthio)corbonyl chloride in dry pyridine, and the latter was also obtained from amino acids and p-methoxybenzyl S-4,6-dimethylpyrimid-2-ylthiocarbonate from p-methoxybenzyl alcohol and (S-4,6-dimethylpyrimid-2-ylthio)carbonyl chloride. These t-butyloxycarbonylation and p-methoxybenzyloxycarbonylation of amino acids are more convenient than the usual methods.

Die Thiolcarbonate (III) werden durch Reaktion der Alkohole (II) mit dem Chlorameisensäureester (I) erhalten.