OF4949, NEW INHIBITORS OF AMINOPEPTIDASE B

II. ELUCIDATION OF STRUCTURE

Abstract

The structures of OF4949-I, II, III and IV were identified by analysis of the products of their chemical degradation and by ¹H NMR, ¹³C NMR, and mass spectrometry. These compounds were new cyclic peptides containing diphenyl ether as a chromophore. OF4949-I had two amino acids, β-hydroxy-L-asparagine and 4-methylisodityrosine. The structural differences between I and II and between III and IV lay solely in the diphenyl ether moiety; the phenolic hydroxyl group in II and IV was methylated in I and III. OF4949-III and IV contained L-asparagine instead of the β-hydroxy-L-asparagine moiety of I and II.