949-45-1Relevant academic research and scientific papers
Efficient syntheses of 13C- and 14C-labelled 5-benzyl and 5-indolylmethyl L-hydantoins
Patching, Simon G.
experimental part, p. 110 - 114 (2011/10/07)
Robust and straightforward methods are described for the first syntheses of highly pure 13C- and 14C-labelled L-5-benzylhydantoin (L-BH) and L-5-indolylmethylhydantoin (L-IMH) by cyclizing the amino acids L-phenylalanine and L-trypto
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.
N-(Hydroxyaminocarbonyl)phenylalanine: A novel class of inhibitor for carboxypeptidase A
Chung, Sang J.,Kim, Dong H.
, p. 185 - 189 (2007/10/03)
N-(Hydroxyaminocarbonyl)phenylalanine (1) was designed rationally as a new type of inhibitor for carboxypeptidase A (CPA). The designed inhibitor was readily prepared from phenylalnine benzyl ester in two steps and evaluated to find that rac-1 inhibits CP
New pyrazole containing bicarboxylic α-amino acids: Mimics of the cis amide bond
De Luca, Lidia,Falorni, Massimo,Giacomelli, Giampaolo,Porcheddu, Andrea
, p. 8701 - 8704 (2007/10/03)
A series of novel optically active α-amino acids, containing a pyrazole ring, which can be regarded as building blocks for peptidomimetics, have been prepared starting from readily available α-amino acids. The synthetic strategy employed allows the regio- and stereoselective preparation of 1,3- or 1,5-substituted pyrazolyl rings. The pyrazole containing peptidomimetics can be considered as analogues of peptides with a cis amide bond.
Synthesis of fused 1,2,5-triazepine-1,5-diones and some N2- and N3-substituted derivatives: Potential conformational mimetics for cis-peptidyl prolinamides
Lenman, Morag M.,Lewis, Arwel,Gani, David
, p. 2297 - 2311 (2007/10/03)
The synthesis of a new fused 1,2,5-triazepine-1,5-dione heterocycle, which is expected to mimic structural features of cis-peptldyl prolinamides, is described. The required parent heterocycle, corresponding to cis-glycy-(2S)-prolinamide, has been prepared in good yield by the cyclisation of N-(2-bromoacetylprolyl)-hydrazine which is itself generated in situ from the bromoacetyl proline methyl ester. Analogues corresponding to cis-(2R)-alanyl- and cis-(2S)-alanyl-(2S)-prolinamide have been similarly prepared from the appropriate N-(2-bromopropionyl)proline methyl esters and hydrazine hydrate where the cyclisation step, involving the displacement of bromide, has been shown to occur with inversion of configuration at C-2 of the propionyl moiety. Acylation at the N-3 position of the triazepine is equivalent to N-terminal acylation of the residue preceding the proline residue in cis-aminoacyl prolinamides. This has been achieved without incident using standard peptide coupling procedures. Extension at the 'C-terminal' has been achieved by preparing elaborated hydrazine precursors which are reacted with suitably activated esters of N-α-halogenoacylprolines, prior to cyclisation, to give the required fused triazepine dione. Thus it is possible to prepare constrained cis-peptidyl prolyl peptide mimetics of defined stereochemistry based upon this new triazepine dione in which all of the non-proline residues can be varied.
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.
Mechanism of Asymmetric Production of L-Aromatic Amino Acids from the Corresponding Hydantoins by Flavobacterium sp.
Yokozeki, Kenzo,Hirose, Yoshiteru,Kubota, Koji
, p. 737 - 746 (2007/10/02)
The mechanism of asymmetric production of L-aromatic amino acids from the corresponding hydantoins by Flavobacterium sp.AJ-3912 was examined by investigating the properties of the enzymes involved in the hydrolysis of 5-substituted hydantoins corresponding to aromatic amino acids (AAH).The enzymatic hydrolysis of AAH by Flavobacterium sp.AJ-3912 consisted of the following two successive reactions; a hydrolytic ring opening reaction of DL-AAH to L- and D-form N-carbamyl aromatic amino acids (NCA), involving an enzyme (hydantoin hydrolase) followed by a hydrolytic cleaving reaction of the L-form NCA to L-aromatic amino acids involving another enzyme (N-carbamyl-L-aromatic amino acid hydrolase, abbreviated as L-NCA hydrolase).The ring opening reaction involving hydantoin hydrolase was not stereospecific, but the NCA cleaving reaction involving L-NCA hydrolase was completely L-specific.The pathway for the conversion of the by-produced D-form NCA to L-aromatic amino acids was as follows; conversion of D-form NCA to D-AAH through the reverse reaction of hydantoin hydrolase, and then conversion of the D-AAH to L-AAH through spontaneous racemization, followed by the successive hydrolysis of the L-AAH to L-aromatic amino acids by hydantoin hydrolase and L-NCA hydrolase.
