L. Ke, Y. Kung, K. Z. Wang
Sep 1, 1964
Citations
0
Influential Citations
1
Citations
Journal
Scientia Sinica
Abstract
Carbobenzoxy-L-seryl-N~(im)-benzyl-L-histidyl-L-leucyl-L-valyl-γ-methyl-L-glutamyl-L-alanyl-L-leucyl-L-tyrosine (B_(9-16a)) and its ethyl ester (B_(9-16)), two derivatives of the octapeptide fragment of the B-chain of insulin, have been synthesized by condensing carbobenzoxy-L-seryl-N~(im)-benzyl-L-histidyl-L-leucine azide with valyl-γ-methyl-L-glutamyl-L-alanyl-L-leucyl-L-tyrosinate and carbobenzoxy-L-seryl-N~(im)-benzyl-L-histidine azide with L-leucyl-L-valyl-γ-methyl-L-glutamyl-L-alanyl-L-leucyl-L-tyrosine ethyl ester (B_(11-16b))respectively. Carbobenzoxy-L-valyl-γ-methyl-L-glutamic acid(B_(12-13a)),prepared by coupling ρ-nitrophenyl carbobenzoxyL-valinate with γ-methyl-L-glutamate, was condensed through its ρ-nitrophenyl ester with L-alanyl-L-leucyl-L-tyrosinate to give the protected pentapeptide(B_(12-16a)).The protected hexapeptide ester(B_(11-16)) was prepared, through the carbodiimide route,by condensing ethyl-L-alanyl-L-leucyl-L-tyrosinate with carbobenzoxy-L-leucyl-L-valyl-γ-methyl-L-glutamic acid (B_(11-13a)), which in turn, was obtained by coupling L-valyl-γ-methyl-L-glutamate with ρ-nitrophenyl carbobenzoxy-L-leucinate. The N-free pentapeptide of B_(12-16a) and the hexapeptide ester (B_(11-16b) were obtained respectively from B_(12-16a) and B_(11-16) by catalytic hydrogenolysis; whereas, the protected di-and tri-peptide esters (B_(9-10) and B_(9-11)), from which the corresponding hydrazides were obtained, were prepared, through the carbodiimide or the azide route, by condensing carbobenzoxy-L-serine with benzyl N~(im)-benzyl-L-histidinate and methyl N~(im)-benzyl-L-histidyl-L-leucinate respectively.