Novel 14-Membered Hexaaza Macrocycles

Abstract

An efficient method for the stereoselective synthesis of novel 14-membered cyclic bis-semicarbazones based on acid-catalyzed cyclization of the hydrazones of 3-(3-oxobutyl)semicarbazides has been developed. The starting semicarbazides were prepared according to a four-step strategy involving amidoalkylation of the sodium enolate of acetylacetone with N-(α-tosylbenzyl)carbamates followed by base-promoted retro-Claisen reaction and treatment of the obtained N-(3-oxobutyl)carbamates with hydrazine.