Synthesis of large macrocyclic tetraaza compounds with a methylene backbone: Cyclo[-NH- (CH2)n-]4, (n = 6, 7, 8, 9 and 10). The formation of 28-, 32-, 36-, 40- and 44-membered rings
Abstract
A series of macrocyclic tetraamines with 28-, 32-, 36-, 40- and 44-membered rings have been efficiently prepared from the corresponding ditosylamide and monobromoalcohol derivatives in 6 steps via a double condensation reaction. Overall yields were: 41, 41, 46, 29, and 33%, respectively, for 1,8,15,22-tetraazacyclooctacontane (11a), 1,9,17,25-tetraazacyclodotriacontane (11b), 1,10,19,28-tetraazacyclohexatriacontane (11c), 1,11,21,31-tetraazacyclotetracontane (11d) and 1,12,23,34-tetraazacyclotetratetracontane (11e).