3154-58-3Relevant articles and documents
Synthesis of specially stable-isotope-labeled L-proline via L-glutamic acid
Cappon, J. J.,Walle, G. A. M. van der,Verdegem, P. J. E.,Raap, J.,Lugtenburg, J.
, p. 517 - 523 (1992)
(3,4-(13)C2)-L-proline and ((15)N)-L-proline were prepared from the correspondingly labeled L-glutamic acids via a single scheme in high yield and on a gram scale.The synthetic route is based on the ring closure of L-glutamic acid to L-5-oxoproline and the selective reduction of the 5-amide function, without interference with the 2-carboxylate function and the asymmetric center.The selective reduction is effected by first converting the amide into the corresponding thioamide and subsequently reducing the thioamide to the amine using tributyltin hydride, in combination with protection and deprotection steps.In earlier work we described the preparation of L-glutamic acid isotopically labeled at any position or combination of positions starting from simple highly enriched synthons.The synthetic scheme in this publication makes L-proline, (13)C- or (15)N-labeled at any position or combination of positions, easily available.The labeled L-prolines are charcterized by (1)H-, (13)C- and (15)N-NMR and mass spectrometry.
Formamide Synthesis through Borinic Acid Catalysed Transamidation under Mild Conditions
Mohy El Dine, Tharwat,Evans, David,Rouden, Jacques,Blanchet, Jér?me
supporting information, p. 5894 - 5898 (2016/04/26)
A highly efficient and mild transamidation of amides with amines co-catalysed by borinic acid and acetic acid has been reported. A wide range of functionalised formamides was synthesized in excellent yields, including important chiral α-amino acid derivatives, with minor racemisation being observed. Experiments suggested that the reaction rely on a cooperative catalysis involving an enhanced boron-derived Lewis acidity rather than an improved Br?nsted acidity of acetic acid. Amide bonds are reputedly difficult to activate due to their high resonance stabilization. An unusual mild activation of dimethylformamide and formamide by borinic acid 1 (see scheme), illustrated by a general formylation of a wide range of amines, including chiral α-amino esters, has been reported.
A remarkably simple protocol for the N -formylation of amino acid esters and primary amines
Suchy, Mojmir,Elmehriki, Adam A. H.,Hudson, Robert H. E.
supporting information; experimental part, p. 3952 - 3955 (2011/09/19)
A simple, convenient, and wide scope protocol for the N-formylation of amino acid esters and primary amines has been developed utilizing only imidazole in warm DMF.
