IMPROVED METHODS OF OBTAINING Nim-TRITYL-SUBSTITUTED HISTIDINE DERIVATIVES

Article abstract of DOI:10.1007/BF00580461

Two variants are proposed for the synthesis of N^α-Boc-N^im-tritylhistidiine.The first variant starts from N^α,N^im-di-Boc-histidine, from which the N^im-Boc group is removed with hydrazine hydrate.The N^α-Boc-histidine formed is esterified with chlorotrimethylsilane, tritylated in the imidazole group, and, after the elimination of the trimethylsilyl protection from the carboxyl group, N^α-Boc-N^im-tritylglycine is obtained with a yield of 80percent.The second variant starts from N^α,N^im-ditritylhistidine, which, by treatment with hydrochloric acid in acetone and then with dilute ammonia, is converted into N^im- tritylhistidine.From this, by acylation with di-tert-butyl pyrocarbonate, N^α-Boc-N^im-tritylhistidine is obtained with a yield of 91percent.The acylation of N^im-tritylhistidine with other alkoxycarbonylating reagents leads to N^α-tert-amyl-, N^α-benzyl-, and N^α-4-methoxybenzyloxycarbonyl derivatives of N^im-tritylhistidine.