Abstract
N-(Coumarin-3-ylcarbonyl)benzotriazole has been coupled with free amino acids, N-ten-ninal-protected lysines and dipeptides to afford fluorescent arnino acids and dipeptides (76-89% yield) with retention of original chirality. N(alpha)- and N(epsilon)-Coumarinlabeled lysines are obtained by simple, two-step procedures. N(alpha)-Cbz-N(epsilon)-(Coumarin-3 -ylcarbonyl)-L-lysinee is demonstrated to be an optically active fluorescent marker for labeling amino acids in solutionphase syntheses.