- Synthesis of hpGRF (Somatocrinin) in liquid phase and intermediate peptides
-
The invention relates to synthesis of hpGRF (Somatocrinin) in liquid phase and to intermediate peptides, comprising:--coupling, one after the other and in the order of the sequence of the GRF, the fragments in which: (a) the side acid functions of the aspartic and glutamic acids and the side amine function of the lysine are protected by protector groups stable in the conditions of deprotection of the group Boc, (b) the guanidine function of the arginine is protected by protonation, and (c) the N-terminal amino acid is protected on the amine by the Boc group;--selectively eliminating the group Boc from the N-terminal amine of the peptide in phase of elongation by hydrolysis with trifluoroacetic acid, said coupling being effected in an aprotic polar solvent and--eliminating, at the end of sequence, all the protector groups by hydrolysis with the aid of a 0.1 to 1M solution of methanesulfonic or trifluoromethanesulfonic acid in trifluoroacetic acid.
- -
-
-
- Carbene Reactions with Cis Azo Functions. Formation of Ester Azines from Δ3-1,3,4-Oxadiazolines
-
Thermolysis of a 2-alkoxy-2,5,5-trialkyl-Δ3-1,3,4-oxadiazoline (1), either neat or in a solvent such as benzene, leads to a carbonyl ylide intermediate which fragments to carbonyl compounds and carbenes.The latter attack the parent oxadiazoline at the azo function, presumably to form azomethine imine ylides.The latter ylides then fragment to form carbonyl compounds and azines such as R1(R2O)C=NN=C(OR2)R1, R1(R2O)C=NN=C(R3)2 and (R3)2C=NN=C(R3)2.The mechanism proposed is supported by results of studies of the dependence of the azine and propeneyields on the initial oxadiazoline concentration.More propene and less (R3)2C=NN=C(R3)2 are obtained at low oxadiazoline concentrations, as would be expected if both arise from dimethyl carbene.
- Keus, Diane,Kaminski, Maciej,Warkentin, John
-
p. 343 - 347
(2007/10/02)
-