65564-08-1Relevant academic research and scientific papers
Serine hydroxymethyl transferase from Streptococcus thermophilus and L-threonine aldolase from Escherichia coli as stereocomplementary biocatalysts for the synthesis of β-hydroxy-α,ω-diamino acid derivatives
Gutierrez, Mariana L.,Garrabou, Xavier,Agosta, Eleonora,Servi, Stefano,Parella, Teodor,Joglar, Jesus,Clapes, Pere
experimental part, p. 4647 - 4656 (2009/05/07)
A novel serine hydroxymethyl transferase from Streptococcus thermophilus (SHMT) and a L-threonine aldolase from Escherichia coli (LTA) were used as stereocomplementary biocatalysts for the aldol addition of glycine to N-Cbz amino aldehydes and benzyloxyacetaldehyde (Cbz = benzyloxycarbonyl). Both threonine aldolases were classified as low-specific L-allo-threonine aldolases, and by manipulating reaction parameters, such as temperature, glycine concentration, and reaction media, SHMT yielded exclusively L-erythro diastereomers in 34-60% conversion, whereas LTA gave L-threo diastereomers in 30:70 to 16:84 diastereomeric ratios and with 40-68% conversion to product. SHMT is among the most stereoselective L-threonine aldolases described. This is due, among other things, to its activity-temperature dependence: at 4°C SHMT has high synthetic activity but negligible retroaldol activity on L-threonine. Thus, the kinetic L-erythro isomer was largely favored and the reactions were virtually irreversible, highly stereoselective, and in turn, gave excellent conversion. It was also found that treatment of the prepared N-Cbz-γ-amino-β-hydroxy-αamino acid derivatives with potassium hydroxide (1M) resulted in the spontaneous formation of 2-oxazolidinone derivatives of the β-hydroxyl and γ-amino groups in quantitative yield. This reaction might be useful for further chemical manipulations of the products.
Studies on the Biosynthesis of Clavulanic Acid. Part 5. Absolute Stereochemistry of Proclavaminic Acid, the Monocyclic Biosynthetic Precursor of Clavulanic Acid
Baggaley, Keith H.,Elson, Stephen W.,Nicholson, Neville H.,Sime, John T.
, p. 1521 - 1533 (2007/10/02)
Proclavaminic acid (1) was synthesized by a route which indicated its constitution to be (2S,3R)-5-amino-3-hydroxy-2-(2-oxoazetidin-1-yl)valeric acid.The spectroscopic properties of the synthetic material were identical with those of natural proclavaminic acid, and, like the natural product, it was converted into clavaminic acid (2) by clavaminic acid synthase.An efficient synthesis of 3-hydroxyornithine derivatives was devised which allowed the separation of diastereoisomers and the resolution of a threo compound by the acylase from Escherichia coli.The β-lactam ring was subsequently elaborated by Michael addition of a protected 3-hydroxyornithine to acrylic acid followed by ring closure using triphenylphosphine/di-2-pyridyl disulphide.Model reactions were carried out with enantiomerically pure threonine derivatives to confirm that the formation of the β-lactam moiety did not impair the integrity of the α- and β-chiral centres and that the enzymatic deacylation reaction was capable of resolving the α-centre of an α-amino-β-hydroxy acid.The enantiomeric purity of intermediates was determined using HPLC, 1H NMR spectroscopy utilising the chiral solvating reagents (R)- and (S)-1-(9-anthryl)-2,2,2-trifluoroethanol, and chiral GLC techniques.
Absolute Stereochemistry of Proclavaminic Acid, the Monocyclic Biosynthetic Precursor of Clavulanic Acid
Baggaley, Keith H.,Nicholson, Neville H.,Sime, John T.
, p. 567 - 568 (2007/10/02)
Proclavaminic acid (1) has been synthesized by a route which indicated the absolute stereochemistry of the two chiral centres to be (2S,3R).
Synthesis of L-Epicapreomycidine
Teshima, Tadashi,Konishi, Kunikazu,Shiba, Tetsuo
, p. 508 - 511 (2007/10/02)
A cyclic guanidino amino acid, L-epicapreomycidine, isolated from hydrolyzates of protease inhibitors such as chymostatin and elastatinal was synthetised.This amino acid is as diastereomer of L-capreomycidine which is a component amino acid of tuberactino
