摘要:
An improvement is described in the synthesis method for N α -trityl-N G -trityl-arginine within a process for preparing N α -fluorenylmethoxycarbonyl-N G -trityl-arginine from arginine, comprising:
a) forming N α -trityl-N G -trityl-arginine b) selectively detaching the trityl group from the α-NH₂ and c) introducing the fluorenylmethoxycarbonyl group in its place.
The improvement consists of preparing the N α -trityl-N G -trityl-arginine by solubilizing the arginine in an aprotic organic solvent by tri-alkylsilylation both of the amino nitrogen and of the carboxyl group, followed by tritylation, with trityl chloride, of the α-amino nitrogen, and of the guanidino group after deprotonating this latter with a bicyclic guanidine. The new improved process can also lead to variable quantities of the arginine analogue di-tritylated at the guanidino group, namely N α -fluorenylmethoxycarbonyl-N G -di-trityl-arginine. This new compound, to which the present invention also relates, can also be used as such in peptide synthesis.
摘要:
The present invention refers to a new class of malonic acid derivatives of general formula I wherein R¹ and R², each independently, represent hydrogen or a carboxyl protecting group, and the residue R corresponds to the side-chain of the amino acids lysine, ornithine, tyrosine, cysteine, aspartic acid and glutamic acid wherein the additional functionalities are suitably protected. The new compounds of the present invention are useful for preparing analogues of biologically active peptides wherein the direction of some amide bonds in which the amino acids lysine, ornithine, tyrosine, cysteine, aspartic acid or glutamic acid are involved, has been reversed.
摘要:
Retro-inverted peptides, analogues of Bradykinin Poten- (I) tiator Pentapeptide (BPP 5a ), definable by the general formula useful as antihypertensives and diagnostics.
摘要:
New retro-inverso analogs of thymopentin (TP5) and of its tripeptide fragment (TP5¹⁻³) of general formula (I) are described wherein R is hydrogen or an acyl radical, and R¹ is -OR² or wherein R² is hydrogen or a hydrocarbyl radical, and the corresponding pharmaceutically acceptable acid- or base-addition salts. The new compounds are enzyme-resistant immunomodulatory peptides.