Enantioselective Peptide Synthesis by Using the Optically Active Polymer Containing the 1-Benzyl-3-Hydroxy-5-Isobutyl-Hydantoin Structure

The polymer containing the 1-benzyl-3-hydroxyhydantoin structure was prepared from styrene and 1-chloromethylhydantotin in order to achieve not only the act as acyl activating polymeric ester but the selective reaction using the D, L-amino acid seter. For the enantioselective peptide senthesis, the 1-benzyl-3-hydroxyhydantoin as a model compound and the 1-bernzyl-3-hydroxyhydantoin type polymer were allowed to act by two methods-the active ester method and the additive method using N, N\u27-dicyclohexylcarbodiimide (DCC). Optical yield was appreciated in 45%

Optically Active 1-Hydroxy-3-Substituted Succinimides for Enantioselective Peptide Synthesis

Optically active 1-hydroxy-3-substituted succinimides were prepared in good yield. The enantioselectivity was evaluated based on specific rotation of dipeptides. 1-Hydroxy-3-substituted succinimide esters of Z-alanine were treated with D, L-ethyl alaninate to indicate 70 and 90% diastereomeric excess of L-L and D-D isomers respectively

Acetohydroxamic Acid for Peptide Synthesis

The ester derivatives of acetohydroxamic acid md N, N-diacetyl hydroxylamine, N, O-diacetyl hydroxylamine and triacetyl hydroxylamine were assured to be capable of being used as activated esters. At first, evaluation of acyl activating ability was made by reacting the above compounds with amine, and it was shown that all of them worked to yield amides with excellent conversion and that, among them, triacetyy hydroxylamine was most powerfull, where acetylation of amines went through its imide carbonyl group. Furthemore, dipeptide synthesis was found to accomplish without any racemization and in a good yield by use of acetohydroxamic acid. Next syntheses of polymers containing hydroxamic acid structure were carried out by the following routes. (a) methyl methacrylate was copolymerized with N-methacrylobenzyloxyamine and the copolymer obtained was debenzylated, (b) N-methacrylo-N, O-diacetyl hydroxylamine was polymerized, followed by hydrolysis and copolymers with styrene or methyl methacrylate were deacylated. The polymer obtained by route (a) was converted to the activated polymer ester of N-blocked diglycine and removal of the protecting group would provide a method for preparation of cyclic diglycine