Aminocarboxylic acid derivs

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. 

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. 

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]. 

BAL is lipid soluble and it has the ability to remove metal deposits not available to attack by other chelators. More effective and less toxic compounds have since become available these include vicinal dithiols, other dithiols, aminocarboxylic acids, cysteine derivatives, and others. Unithiol (sodium 2,3-dimercaptopropane-l-sulfonate DMPS) forms very stable, water soluble complexes with Hg2+, Pb2+, Cd2+, Zn2+, Bi3+, As3+, Sb2+ and Ni2+. The complexes are nearly all less toxic than... 

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... 

Finally, the Mannich bases derived from cycloalkanones undergo photolysis in aqueous medium (Fig. 149) to give w-aminocarboxylic acids 373. 

Ring closure with the formation of a carbon-nitrogen bond, of the types A-E shown in Fig. 1, has been used to synthesize derivatives of 1-, 2-, and 3-benzazepines, with aminocarboxylic acids, amino halides, dihalides, dinitriles, dicarboxylic acids, and carboxylic acid diamides as starting materials. The yields were generally fair to good. In some cases preferential formation of a five- or six-membered ring was observed. 

Peptide formation with an A-protected, optically pure aminocarboxylic acid is an alternative means of obtaining diastereoisomeric derivatives of chiral aminoalkylphos-phonic acids, the diastereoisomeric products being distinguishable on a quantitative basis by P NMR spectroscopy for example, A-boc-L-alanine was used to distinguish the enantiomers of diethyl (a-aminobenzyl)phosphonate. The reaction between an enan-tiomerically enriched sample of 125 (R = H) and L-leucine methyl ester hydrochloride in the presence of DCC was followed by HPLC separation of the l,l- and D,L-peptides 126 (R = H ratio 95.3 4.7), and essentially the same procedure was applied to an analysis of 125 (R = OCH2Ph), as prepared using the bislactim ether procedure (see Section IV. C.2.b) when the final product consisted of a mixture of R,S and S,S diastereoisomers in the ratio 87.4 12.6 ... 

The reactions of phosphorous acid are paralleled still further by the additions of hypophosphorus acid to azomethines in practice, mixtures of amines and carbonyl reactants may be employed ", but the drawbacks to the procedure found for the synthesis of aminoalkylphosphonic acids may well apply here also. In a valuable publication, Dingwall and coworkers described the syntheses of (aminoalkyl)phosphinic acid analogues of many of the naturally occurring aminocarboxylic acids by the simple treatment of the benzyhydrylimine derivatives of the necessary amines with hypophosphorous acid, formed in situ when diphenylmethylammonium hypophosphite is treated with an appropriate aldehyde this step is followed by removal of the A -protection with 48% aqueous HBr, with 18% aqueous HCl or with trifluoroacetic acid in boiling methoxybenzene any second amino group was protected as the phthalimido derivative. 

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