Practical Synthesis of Active Esters of 4-Alkoxycarbonylamino-3-methoxypyrrole-2-carboxylic Acid

Abstract

An efficient large scale synthesis of the HOAt active ester of 4-tert-butoxycarbonylamino-3-methoxypyrrole-2-carboxylic acid is reported.

Total Synthesis of Leupyrrin B1: A Potent Inhibitor of Human Leukocyte Elastase

“…In contrast, the coupling of separately prepared 17 with isopropylamine proceeded quantitatively. Hence, we focused on the initial formation of azabenzotriazole 17 . Decreasing the reaction temperature dramatically increased the yield of 17 (entry 2), while an even improved conversion was observed by reducing excess HATU (entry 3).…”