Fluorescent labeling of peptides on solid phase.

N(alpha)-Fmoc-N(epsilon)-[(7-methoxycoumarin-4-yl)acetyl]-L-lysine (N(alpha)-Fmoc-L-Lys(Mca)-OH) 3 is conveniently prepared by benzotriazole methodology (52% over two steps). N-Acylbenzotriazoles Mca-Bt 2, N(alpha)-Fmoc-L-Lys(Mca)-Bt 4, coumarin-3-ylcarbonyl (Cc)-Bt 5, N(alpha)-Fmoc-L-Lys(Cc)-Bt 7 and N(alpha)-(Cc)-L-Lys(Fmoc)-Bt 9 enable the efficient microwave enhanced solid-phase fluorescent labeling of peptides.