18409-49-9Relevant academic research and scientific papers
Microwave-assisted synthesis of N-monosubstituted urea derivatives
De Luca, Lidia,Porcheddu, Andrea,Giacomelli, Giampaolo,Murgia, Irene
scheme or table, p. 2439 - 2442 (2010/11/18)
An easy and rapid procedure for the preparation of N-monosubstituted ureas via reaction between potassium cyanate and a wide range of amines is described. The procedure was performed under microwave irradiation using water as solvent. This methodology is particularly attractive since it provides ureas in high yield and purity. Georg Thieme Verlag Stuttgart · New York.
Rapid and efficient microwave-assisted synthesis of N-carbamoyl-L-amino acids
Verardo, Giancarlo,Geatti, Paola,Strazzolini, Paolo
, p. 1833 - 1844 (2008/02/02)
A rapid and efficient method for the synthesis of N-carbamoyl-L-amino acids is reported. The procedure, involving the reaction between urea and α-amino acids sodium salts, was performed under microwave conditions using an unmodified domestic microwave oven. A careful study of the operative conditions indicated proline (1d) as the less reactive substrate and phenylglycine (1e) as the more reactive one among all the α-amino acids tested. Substitution of urea with potassium cyanate produced a low conversion into the corresponding N-carbamoyl derivative, and a possible explanation of this result is reported. Copyright Taylor & Francis Group, LLC.
A pH-dependent cyanate reactivity model: Application to preparative N-carbamoylation of amino acids
Taillades, Jacques,Boiteau, Laurent,Beuzelin, Isabelle,Lagrille, Olivier,Biron, Jean-Philippe,Vayaboury, Willy,Vandenabeele-Trambouze, Odile,Giani, Olivia,Commeyras, Auguste
, p. 1247 - 1254 (2007/10/03)
Recent developments in peptide synthesis have underlined the importance of optimising, on a preparative scale, the N-carbamoylation of amino acids by aqueous cyanate. To this purpose, a theoretical model of aqueous cyanate reactivity was designed. The parameters of the model were evaluated, for various pH and temperatures, from a critical survey of the literature, together with additional experimental data. Computer-simulated kinetics based on this model showed the reaction efficiency to be significantly dependent on pH, and suggested optimum conditions to be moderate temperatures and pH 8.5-9. Discussion of the practical convenience of these theoretical results led us to prefer 40-50 °C and a pH range of 7-8 as reaction conditions, thus maintaining reaction times within a few hours. Various N-carbamoyl amino acids (ureido derivatives of glycine, L-valine, L-alanine, L-leucine, DL-methionine, Nε-trifluoroacetyl-L-lysine, β-alanine) were thus successfully synthesised on the gram to kilogram scales.
Mechanism of Stereospecific Production of L-Amino Acids from the Corresponding 5-Substituted Hydantoins by Bacillus brevis
Yamashiro, Akihiro,Kubota, Koji,Yokozeki, Kenzo
, p. 2857 - 2864 (2007/10/02)
The mechanism of stereospecific production of L-amino acids from the corresponding 5-substituted hydantoins by Bacillus brevis AJ-12299 was studied.The enzymes involved in the reaction were partially purified by DEAE-Toyopearl 650M column chromatography and their properties were investigated.The conversion of DL-5-substituted hydantoins to the corresponding L-amino acids consisted of the following two successive reactions.The first step was the ring-opening hydrolysis to N-carbamoyl amino acids catalyzed by an ATP dependent L-5-substituted hydantoin hydrolase.This reaction was stereospecific and the N-carbamoyl amino acid produced was exclusively the L-form.N-Carbamoyl-L-amino acid was also produced from the D-form of 5-substituted hydantoin, which suggests that spontaneous racemization occurred in the reaction mixture.In the second step, N-carbamoyl-L-amino acid was hydrolyzed to L-amino acid by an N-carbamoyl-L-amino acid hydrolase, which was also an L-specific enzyme.The ATP dependency of the L-5-substituted hydantoin hydrolase was supposed to be the limiting factor in the production of L-amino acids from the corresponding 5-substituted hydantoins by this bacterium.
PRACTICAL SYNTHESIS OF OPTICALLY ACTIVE α-HYDRAZINO ACIDS FROM α-AMINO ACIDS
Viret, Joelle,Gabard, Jacqueline,Collet, Andre
, p. 891 - 894 (2007/10/02)
Simple amino acids (1) can be converted in fair to good yield into hydrazino acids (3) of like configuration by using KOCl instead of NaOCl to promote the Shestakov rearrangement of the intermediate hydantoic acids (2).
