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