62088-03-3

Upstream product

• 13649-97-3 (S)-4-benzyl-2-methyl-4H-oxazol-5-one 
• 15028-44-1 DL-phenylalanine methyl ester 
• 80165-37-3 Ac-ΔPhe-(R)-Phe-OMe 
• 82690-96-8 N-Acetyldehydrophenylalanylphenylalanine methyl ester 
• 109927-10-8 racemic Ac-Phe-ΔPhe-OMe 

Relevant academic research and scientific papers

ASYMMETRIC SYNTHESIS OF AMINO ACIDS VIA THE CATALYTIC REDUCTION OF SUBSTITUTED ACYLAMINOACRYLIC ACID AZLACTONES. 26. AMINOLYSIS OF 2-METHYL-4-BENZYLOXAZOLIN-5-ONE UPON REACTION WITH S-PHENYLALANINE DERIVATIVES

The kinetics of aminolysis and racemization of 2-methyl-4-benzyloxazolin-5-one upon reaction with S-phenylalanine methyl ester have been studied in dimethoxyethane solvent.The rates of aminolysis and racemization are comparable.Addition of an achiral component, namely Et3N, to the reaction mixture, however, dramatically increases the rate of racemization.The presence of Et3N also increases the ratio of rate constants for the formation of RS- and SS-diastereomers, which determines the reaction stereoselectivity.

Efficient 1,4-Asymetric Induction Utilizing Electrostatic Interaction between Ligand and Substrate in the Asymmetric Hydrogenation of Didehydrodipeptides

Electrostatic interaction between the amino group of the achiral 3-dimethylaminopropylidenebismethylenebis(diphenylphosphine) (1) and the carboxy group of the substrate enable an effective 1,4-asymmetric induction in the RhI-catalysed hydrogenation of didehydrodipeptides, to give (S,S)-or (R,R)-products selectively.The selectivity reached up to 94percent diastereoisomeric excess with acetyl didehydrodipeptides and 92percent with benzyloxycarbonyl substrates.

ASYMMETRIC HOMOGENOUS REDUCTION OF DEHYDROPEPTIDES

Monodehydropeptides with the dehydroaminoacid fragment in C-terminal or N-terminal position were synthetized as well as a family with the general formula Ac-ΔPhe-(Gly)n-Leu-OR (n = 0-2, R = H or Me).Asymmetric reduction of these compounds catalyzed by chiral rhodium complexes was investigated.The results were discussed in terms of double asymmetric induction.A method was developped to avoid the use of both enantiomers of the substrate or of the catalyst, it consists in the total reduction of a racemic dehydropeptide.The products distribution gives access to the two desired facial selectivities.

ASYMMETRIC HYDROGENATION OF DEHYDROAMINO ACIDS AND DEHYDRODIPEPTIDES WITH RHODIUM(I)-MODIFIED DIOP CATALYSTS.

( minus )-DIOP was modified in two ways: i), introduction of a large aromatic substituent at the dioxolane ring of ( minus )-DIOP and ii), replacement of one diphenylphosphino group by diarylphosphino group to give unsymmetrical DIOPs. Modification at the dioxolane ring had a small effect on the asymmetric induction by DIOP in the hydrogenation. Modification at the phosphino group affected the stereocontrol by the ligand and the unsymmetrical DIOP with di-2-naphthylphosphino group gave higher optical yields than ( minus )-DIOP for the hydrogenation of alpha -acetamidocinnamic acid and dehydrodipeptides.

ASYMMETRIC HYDROGENATION OF DEHYDRODIPEPTIDES WITH RHODIUM(I)-CHIRAL DIPHOSPHINITES. SELECTIVE (S,S)- AND (R,R)-PRODUCT FORMATION BY DOUBLE ASYMMETRIC INDUCTION.

In the hydrogenation of dehydrodipeptides, the effect of chiral center of the substrate ((S) or (R)) on the asymmetric induction was examined using the catalysts of Rh(I)-chiral diphosphinite containing pyrrolidine moiety (POP). The catalysts with POP's h

Synthesis of Chiral Dipeptides by means of Asymmetric Hydrogenation of Dehydro Dipeptides

Asymmetric hydrogenation of various dehydro dipeptides was carried out by using rhodium complex catalysts with a variety of chiral diphosphine ligands.The efficiency of chiral diphosphine ligands as well as the effect of the chiral center in the substrate