78816-88-3Relevant articles and documents
C(sp3)?H Cyanation Promoted by Visible-Light Photoredox/Phosphate Hybrid Catalysis
Wakaki, Takayuki,Sakai, Kentaro,Enomoto, Takafumi,Kondo, Mio,Masaoka, Shigeyuki,Oisaki, Kounosuke,Kanai, Motomu
supporting information, p. 8051 - 8055 (2018/06/15)
Inspired by the reaction mechanism of photo-induced DNA cleavage in nature, a C(sp3)?H cyanation reaction promoted by visible-light photoredox/phosphate hybrid catalysis was developed. Phosphate radicals, generated by one-electron photooxidation of phosphate salt, functioned as a hydrogen-atom-transfer catalyst to produce nucleophilic carbon radicals from C(sp3)?H bonds with a high bond-dissociation energy. The resulting carbon radicals were trapped by a cyano radical source (TsCN) to produce the C?H cyanation products. Due to the high functional-group tolerance and versatility of the cyano group, the reaction will be useful for realizing streamlined building block syntheses and late-stage functionalization of drug-like molecules.
Inverse peptide synthesis via activated α-aminoesters
Suppo, Jean-Simon,Subra, Gilles,Berges, Matthieu,Marcia De Figueiredo, Renata,Campagne, Jean-Marc
, p. 5389 - 5393 (2014/06/09)
A mild, practical, and simple procedure for peptide-bond formation is reported. Instead of activation of the carboxylic acid functionality, the reaction involves an unprecedented use of activated α-aminoesters. The method provides a straightforward entry to dipeptides and was effective when a sensitive cysteine residue was used, as no epimerization was detected in this case. The applicability of this method to iterative peptide synthesis was illustrated by the synthesis of a model tetrapeptide in the challenging reverse N→C direction. How to advance by going into reverse: In a mild and practical procedure for peptide-bond formation, free α-aminoesters were activated by treatment with N,N′-carbonyldiimidazole, instead of activating the carboxylic acid functionality (see scheme). The method provided a straightforward route to dipeptides, and its applicability to iterative peptide synthesis was illustrated by the synthesis of a tetrapeptide in the challenging reverse N→C direction.
KINETICS OF THE ALKALINE HYDROLYSIS OF SEVERAL N-BENZYLOXYCARBONYLDIPEPTIDE METHYL AND ETHYL ESTERS
Hoogwater, D. A.,Peereboom, M.
, p. 5325 - 5332 (2007/10/02)
The reaction rates of the alkaline hydrolysis of synthesized N-protected dipeptide methyl and ethyl esters were studied systematically.From the kinetic data the energies of activation, the pre-exponential factors and the reference values at 40 deg C were calculated.The rate of hydrolysis shows to be strongly dependent on the C-terminal amino acid in the sequence Gly >> Ala/Met/Phe > Leu >> Val/Pro.Surprisingly the N-terminal amino acid also exerts an effect, but in a different sequence.N-Terminal Phe in particular shows a relative accelerating effect.Remarkable is the significantly faster ester hydrolysis of glycine containing dipeptide ethyl esters in ethanol/water compared to the corresponding methyl esters in methanol/water.