Antineoplastic agents. 109. Structural biochemistry. 24. Synthesis of the cyclo-[(gly) Thz-(R)-and (S)-(gln) Thz-L-Val-L-Leu-L-Pro] isomers of dolastatin 3

GR Pettit, PS Nelson, CW Holzapfel

Index: Pettit, George R.; Nelson, Paul S.; Holzapfel, Cedric W. Journal of Organic Chemistry, 1985 , vol. 50, # 15 p. 2654 - 2659

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Citation Number: 18

Abstract

+-02CCF3'R'= Tcp c matographic purification of dipeptide 3. A relatively poor yield (27 7%) resulted when Boc-L-Leu-L-Pro-OMe was deprotected with trifluoroacetic acid-methylene chloride (1: l) and coupled with the mixed carbonic anhydride derivative of Boc-L-Val to afford tripeptide 5. Cleavage of the Boc group with dry ethereal hydrogen chloride gave L- Val-L-Leu-Pro-OMe (6) eHCl in 98% yield. Condensation of L-Leu-L-Pro-OMe. HC1 with ...