A aminocarboxylic acid

The beneficial effect of surfactants on enantioselective hydrogenations in water was exploited in the synthesis of a-aminophosphinic and a-aminophosphonic acids. These compounds are stmctural analogues of a-aminocarboxylic acids and their peptides find use as herbicides, bactericides and antibiotics [150,151]. With [Rh(BPPM)(COD)]Bp4 and similar catalysts fast ractions and e.e.-s up to 98% could be obtained in water in the presence of SDS (Scheme 3.12). 

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. 

The degradation of a-aminocarboxylic acids has proven to be a useful method for the preparation of iminium salts. For example, treatment of N- methylpipecolic acid (97) with phosphorus oxychloride gave 94% of the iminium salt (98) (Scheme 7) (76JA7448). The synthetic utility of this approach is illustrated by the synthesis of tetrahydroberberine (Scheme 8) (78JOC2115). The advantage of this method for the preparation of iminium salts is that the position of the carbon-nitrogen double bond can be controlled. 

Protonation of amines, carboxylate anions and a-aminocarboxylic acids causes considerable upfield shifts, particularly in the position fi to the protonated group [84, 95-98] ... 

Aminoalkylphosphonic acids are analogues of natural a-aminocarboxylic acids and are designated by generally accepted three-letter abbreviations for the amino acid residue followed by a superscript P. For example, 1-aminoethylphosphonic acid, which is related to alanine, is abbreviated as Alap. Diphenyl [l-(benzyloxycarbonylamino)ethyl]phosphonate, is abbreviated as Z-Alap(OPh)2. The l-aminoalkylphosphonic acids have modest water solubility, which significantly increases in strong acidic and alkali solution. They are not soluble... 

The a-aminocarboxylic acids are of particular importance as the result of their involvement in the primary structure of protein molecules. Although customarily represented by the general formula NHj CHR-CC H amino acids are... 

Initially, an arylamine does not react as an activated aromatic compound with sulfuric acid but as a base instead anilinium hydrogen sulfates are produced (Figure 5.18). However, when the latter are heated, they decompose to give the starting materials reversibly. Only via the very small equilibrium amounts of free amine and free sulfuric acid does one observe the slow formation of the substitution product, an aromatic aminosulfonic acid. This aminosulfonic acid is a zwitterion, like an a-aminocarboxylic acid. 

Phenyl tellurium cyanide and co-halo-a-aminocarboxylic acids were claimed to react to yield phenyl co-amino-cu-carboxyalkyl telluriums3. 

Reufer Ch., Hateley, M., Lehmann, Th., Weckbecker, Ch., Sanzenbacher R. and Bilz, J. (2006) Process for the preparation of a-substituted carboxylic acids from the series comprising a-hydroxycarboxylic acids and N-substituted a-aminocarboxylic acids. European patent EP... 

The reaction product obtained from diphenylcarbodiimide and hydrogen cyanide is an intermediate in Sandmeyers indigo synthesis. HCN can also be eliminated from a-aminocarboxylic acid nitriles 589 to give l-cyano-N,N -disubstituted formamidines 590 and imines 591. ... 

Decarboxylative acetoxylation and methoxylation of a-aminocarboxylic acids proceed smoothly, yielding synthetically useful intermediates. For example, the versatile intermediate (LX) for the synthesis of thienamycine is prepared by electrodecarboxylative acetoxylation of 4-carboxy-2-azetidinone (LIX) in an AcOH-MeCN-AcONa-(Pt) system [134] ... 

The four component condensation (Ugi reaction) " converts a mixture of substituted amine, isonitrile, aldehyde (or ketone) and carboxylic acid (Scheme 6) to a-acylaminocarboxylic acid amides (pathway a), to diacylamines (pathway b) and to a-aminocarboxylic acid amides (pathway... 

Naskar, D., Roy, A., Seibel, W. L., Portlock, D. E. Hydroxylamines and sulfinamide as amine components in the Petasis boronic acid-Mannich reaction synthesis of N-hydroxy or alkoxy-a-aminocarboxylic acids and N-(tert-butyl sulfinyl)-a-amino carboxylic acids. 

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