DNA-BINDING COMPOUNDS .4. SYNTHESIS AND SOLUTION CONFORMATION OF A NOVEL MACROCYLE FORMED BY COUPLING OF THE SIDE-CHAINS OF ADJACENT L-LYSINE RESIDUES

The novel macrocyclic dilysine derivatives (8S,11S)-11-t-butoxycarbonylamino-2,10-dioxo-1,3,9-triazacyclopentadecane-8-carboxylic acid methyl (5) and t-butyl (6) esters were prepared by coupling of the epsilon-amino groups of adjacent lysine residues of the esters of Boc-Lys-Lys-OR with 1,1'-carbonyldiimidazole under mild conditions. The conformation of (6) in dimethyl sulfoxide solution was determined by the use of a variety of one- and two-dimensional n.m.r. techniques.