A-Aminocarboxylic acid derivs

Conversion of racemates to one stereoisomer via salts and racemization a-Aminocarboxylic acid derivatives... 

Dry methyl methylthiomethyl sulfoxide allowed to react at room temp, with NaH in tetrahydrofuran, benzonitrile added, and stirred 16 hrs. at 50 l-methylsulfinyl-l-methylthio-2-amino-2-phenylethylene. Y 75%. - This is the first step of a method for the synthesis of a-aminocarboxylic acid derivs. from nitriles with addition of 1 C-atom. F. e. s. K. Ogura and G. Tsudiihashi, Am. Soc. 96,1960 (1974). 

Chiral carboxyamides derived from acid chlorides and A-chiral cA-aminoindanol can be protonated and Li Cu transmetallated to generate copper enolates which react with A-lithium derivative of A-Boc-O-tosylhydroxylamine (LiBTOC) 31 to give a-A-Boc amino carboxamides in high yields and enantiomeric excess (Scheme 38) . The chiral auxiliary can be removed by acidic hydrolysis to obtain the a-aminocarboxylic acid. 

Cycloadditions. In the presence of this catalyst and a base, allylamines and acrylates undergo cycloaddition to give cyclobutane- -aminocarboxylic acid derivatives. The reaction involves prior isomerization of the allylamine to an enamine, which then undergoes thermal cycloaddition with the acrylate. 

N-Protected a-aminocarboxylic acid amides. A soln. of N-(4-methoxybenzyloxycar-bonyl)alanine in 4 1 dichloromethane/dimethylformamide treated with 1-hydroxy-benzotriazole and dicyclohexylcarbodiimide, stirred for 30 min, 25% aq. NH3 added, and stirred for 3-5 h until reaction complete (t.l.c.) - N-(4-methoxybenzyloxycar-bonyl)alanine amide. Y 83%. The method is high-yielding and racemization-free. F.e. inch Boc- and Cbz-aminoacid and dipeptide derivs. s. S.-T. Chen et al.. Synthesis 1989, 37-8 with 2-ethoxy-N-ethoxycarbonyl-l,2-dihydroquinoline and NH4HCO3 cf. S. Nozaki, I. Muramatsu, Bull. Chem. Soc. Japan 61, 2647-8 (1988). 

Isothiazolidine 1-oxides from a-aminocarboxylic acids and ethylene derivs. via 1,3-dipolar cycloaddition... 

Synthesis of a-aminocarboxylic acids from bromides Br - C(NHAc)(COOR)2 via acetylaminomalonic acid esters cf. 22, 837 via formamidomalonates with NaOEt/ EtOH as base, polyfluoroalkoxy- and polyfluoroalkylthio-phenylalanine derivs., s. M.T. Kolycheva et al., Zh. Org. Khim. 25, 1306-11 (1989). 

A soln. of alanine in 2 iV NaOH warmed 5 min. with a-acetyl- -ethoxy-N-ethoxy-carbonylacrylamide 5-acetyluracil-l-a-methylacetic acid. Y 75-100%.—The products are useful derivatives of a-aminocarboxylic acids. They are immune to hydrolysis by strong acids and may be used for the determination of N-terminal moieties in proteins. F. e., also from peptides and proteins, s. J. H. Dewar and G. Shaw, Soc. 1961, 3254. 

Pyrrole derivatives s. 11, 153 p-Dimethylaminobenzaldehyde Amines from a-aminocarboxylic acids s. 13, 142... 

Reactions with active cyclic derivatives of a-aminocarboxylic acids... 

A review of the methods which facilitates the rapid choice of an optimum procedure to be used for the determination of procaine and other medicinals derived from aminocarboxylic acids has have been published [28]. This review covers volumetric, optical, electrochemical and polarographic methods. 

A frequently employed route comprises preparation of 3-alkoxycar-bonyltetramic acids from malonic acid derivatives and a-aminocarboxylic esters (77MI1 84CPB3724) or, alternatively, a-aminonitriles (86UP1) followed by hydrolysis and decarboxylation [72JCS(P1)2121 85AJC1847 86ZN(B)219]. 

Adamic and Bartak [6] used high pressure aqueous size exclusion chromatography with reverse pulse amperometric detection to separate copper(II) complexes of poly(amino carboxylic acids), catechol and fulvic acids. The commercially available size exclusion chromatography columns were tested. Columns were eluted with copper(II) complexes of poly(aminocarboxylic acids), citric acids, catechol and water derived fulvic acid. The eluent contained copper(II) to prevent dissociation of the labile metal complexes. Reverse pulse electrochemical measurements were made to minimise oxygen interferences at the detector. Resolution of a mixture of DTP A, EDTA and NTA copper complexes was approximately the same on one size exclusion chromatography column as on Sephadex... 

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