14- and 17-Membered Macrocycles Containing Amide, Amino, and Carbamate Groups in The Monocyclic Skeleton: An Accidental Byproduct Obtained from a Residue after Separation.

A 14-membered cyclic compound ( 3 ) containing amide, amino, and carbamate groups, which was serendipitously obtained in the oily residue after the separation of 4-benzyl-1,4,7,10-tetraazacyldododecane-2,6-dione ( 2a ) and 4,16-dibenzyl-1,4,7,10,13,16,19,22-octaazacyclo-tetracosane-2,6,14,18-tetraone ( 2b ), is reported. The structure of 3 is formally a CO 2 insertion between positions 3 and 4 of the 12-membered ring in 2a . The CO 2 insertion was confirmed in the synthesis of diethyl 2,2'-(benzylazanediyl)diacetate ( 1 ) by the reaction of benzylamine with ethyl bromoacetate using K 2 CO 3 as the base. In addition, the selective synthesis of 3 and ethyl N -benzyl- N -((2-ethoxy-2-oxoethoxy)carbonyl)glycinate ( 5 ) and their kinetic behavior are reported. The reaction of 5 with triethylenetetramine afforded a 17-membered macrocycle ( 7 ), which was obtained in an 18% yield. Compounds 6 and 8 were prepared from 3 and 7 by introducing benzyl groups to improve their solubility in organic solvents. Titration experiments using 1 H NMR showed that both 6 and 8 exhibit Li + selectivity.