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Studies on Amino Acids and Peptides, 11. Synthesis of Four MIF Analogues Containing an N-Terminal (S)-5-Thioxoprolyl Residue

✍ Scribed by Andersen, Torben P. ;Senning, Alexander


Publisher
John Wiley and Sons
Year
1987
Tongue
English
Weight
608 KB
Volume
1987
Category
Article
ISSN
0947-3440

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✦ Synopsis


The newly synthesized amino acid (S)-5-thioxoproline ((sj-Top OH) (1) has been coupled with HCI * H-(S)-Leu-GlyNRR 6 by the mixed anhydride method. The resulting tripeptide amides (Sy-Top-(Sf-Leu-GlyNRR' 7 are new analogues of the hypothalamic factor MIF. The intermediatcs 6 were synthesiirzd by aminolysis of Boc-(S)-Leu-GlyOEt with the corresponding amine HNRR followed by removal of the Boc group by 4 M HCl/dioxane. In two syntheses of 7 the corresponding N-carboxylated tripeptide amide 8 was isolated. i.e. isobutyl chloroformate had reacted with 1. Decreasing the amount of isobutyl chloroformate used and the activation time decreases the amount of 8 formed.