N-methyl-L-phenylalanine

The vast majority of amino acid dehydrogenases use ammonium ions as the amine donor. However, recently a novel N-methyl-L-amino acid dehydrogenase (NMAADH), from Pseudomonas putida, was isolated and used to synthesize N-methyl-L-phenylalanine 36 from phenylpyruvic acid 31 and methylamine 35 in 98% yield and greater than 99%e.e. (Scheme 2.15). The enzyme was shown to accept a number of different ketoacids and also use various amine donors. Glucose dehydrogenase from Bacillus suhtilis was used to recycle the NADPH cofactor [17]. 

The mixture of amino acids released by complete hydrolysis of lipopeptin A was fractionated by ion-exchange chromatography. Each amino acid was isolated and the optical rotation determined. Two moles of L-aspartic acid and 1 mole each of L-glutamic acid, L-serine, l-threonine, N-methyl-L-phenylalanine, L-threo-p-hydroxyglutamic acid and N-methyl-L-aspartic acid were obtained. 

The influence of a large number of oc-amino acids on the values of and k at have been determined. These a-amino acids included glycine, L-valine, L-leucine, L-phenylalanine, L-tyrosine, L-tryptophan, NOrmethyl-L-tryptophan (L-abrine), N-methyl-L-tyrosine, N,N-dimethyl-L-tyrosine and p -me thoxy-N-me thyl -L -phenyl al anine. 

Petkov, Christova, and Stoineva (11) have reported a study on the hydrolysis of N-acetyl-l.-phenylalanine anilide derivatives with o-chymotrypsin N-methylated anilides 34 (R CHj) were found to be unreactive under the conditions used for the hydrolysis of N—H anilides 34 (R=H). These authors have explained their results in a manner analogous to that described above, i,e. no hydrolysis takes place because steric hindrance caused by the N-methyl group prevents the formation of a tetrahedral intermediate in the N-methyl anilide derivatives. 

Subsequently, shallow water collections of Lyngbya majuscula from Puerto Rico and the Dry Tortugas yielded additional supplies of ATX as well as a new congener termed antillatoxin B (Figure 6.10) [149]. The structure of the new metabolite was determined largely by comparison with the spectroscopic data set for ATX, and stereochemistry deduced by Marfey s analysis for L-alanine while the i-N-methyl homophenylalanine was proposed based on nuclear Overhauser effect (nOe) and bioassay results. Substitution of i-N-methyl homo-phenylalanine, an intriguing amino acid of quite rare occurrence in natural products, for i-N-methyl valine... 

Recently, Cocinero et al. reported that N-acetyl-L-phenylalanine can bind to methyl o-galactose, and claimed that the anomeric effect can be... 

Discuss the differences observed in the IR and NMR spectra of N-ferf-butoxy-carbonyl-L-alanine, methyl L-phenylalaninate hydrochloride, and methyl N-ferf-butoxycarbonyl-L-alanyl-L-phenylalaninate that are consistent with the formation of the latter in this procedure. 

N-Bromoacetyl-N-methyl-h-phenylalanine. This is prepared by acyl-ating iV-methyl-L-phenylalanine with bromoacetyl bromide in alkaline solution. The product is crystallized from ethanol-water m.p. 109°. 

N-tosyl-L-phenylalanine ethyl ester (Formula 2.18) is a suitable substrate for the proteinase chymotrypsin which hydrolyzes ester bonds. When the ethoxy group is replaced by a chloro-methyl group, an inhibitor whose structure is similar to the substrate is formed (Na-tosyl-L-phenylalanine chloromethylketone, TPCK). 

N-Acetyl-DL-phenylalanine-N-methylamide, 40B, 457 N-Acetyl-L-phenylalanine-N-methylamide, 43B, 608 N-Acetyl-L-tyrosinemethylamide, 39B, 362 40B, 456 Cyclo(L-seryl-L-tyrosyl) monohydrate, 39B, 360 Methyl L-pyroglutamyl-L-histidine, 39B, 362 N(a)-Acetyl-aza-a-homo-phenylalanine methylamide, 45B,... 

C17H12N2O2, Cyclo-N-methyl-L-alanyl-L-alanyl, 42B, 366 C17H13NO1, Phthalylphenylalanine, 41B, 552 Cl7H17N3O5, N-Acetyl-L-tyrosine-p-nitroanilide, 42B, 367 C17H19BrN20eS, Glycyl-L-phenylalanine p-bromobenzenesulphonate, 38B, 498... 

Cyclobis(N-methyl-L-phenylalanyl), 42B, 358 N-Acetyl L phenylalanyl-L-tyrosine, 39B, 365 Carbobenzoxy-L-leucyl-p-nitrophenyl ester, 40B, 462 6, L-Threonyl-L-phenylalanine-p-nitrobenzyl ester hydro-bromide, 34B, 274... 

Although, a-chymotrypsin is sterospecific toward the L-isomer of most amino acid substrates, Niemann showed that the stereospecificity is reversed in the case of KCTI. The D-isomer of this conformationally restricted ester is hydrolyzed at a rate comparable to that of N-acetylated L-phenylalanine methyl esters while the L-isomer is hydrolyzed very slowly. Hein and Niemann (101,102) pointed out that this anomaly is consistent with a requirement for the carboxylate group of d-KCTI to be in an axial conformation, a conformation which matches a probable conformation of open-chain l-amino acid ester substrates. 

Chemical Name N-L-a-Aspartyl-L-phenylalanine 1-methyl ester Common Name —... 

A solution of 88.5 parts of L-phenylalanine methyl ester hydrochloride in 100 parts of water is neutralized by the addition of dilute aqueous potassium bicarbonate, then is extracted with approximately 900 parts of ethyl acetate. The resulting organic solution is washed with water and dried over anhydrous magnesium sulfate. To that solution is then added 200 parts of N-benzyloxycarbonyl-L-aspartic acid-a-p-nitrophenyl, -benzyl diester, and that reaction mixture is kept at room temperature for about 24 hours, then at approximately 65°C for about 24 hours. The reaction mixture is cooled to room temperature, diluted with approximately 390 parts of cyclohexane, then cooled to approximately -18°C in order to complete crystallization. The resulting crystalline product is isolated by filtration and dried to afford -benzyl N-benzyloxycarbonvI-L-aspartyl-L-phenylalanine methyl ester, melting at about 118.5°-119.5°C. 

To a solution of 180 parts of -benzyl N-benzyloxycarbonyl-L-aspartvI-L-phenylalanine methyl ester in 3,000 parts by volume of 75% acetic acid is added 18 parts of palladium black metal catalyst, and the resulting mixture is shaken with hydrogen at atmospheric pressure and room temperature for about 12 hours. The catalyst is removed by filtration, and the solvent is distilled under reduced pressure to afford a solid residue, which is purified by re-crystallization from aqueous ethanol to yield L-aspartyl-L-phenylalanine methyl ester. It displays a double melting point at about 190°C and 245°-247°C. 

The N-carboxybenzoyl compound (2.7 g) was refluxed for 30 minutes with acetic anhydride (10 ml), the mixture taken to dryness (vacuum) and the residue heated with water. The cooled gummy product became granular on rubbing and crystallized from methyl ethyl ketone-petrol or aqueous ethanol in almost colorless needles, MP 184° to 186°C, of p-nitro-N-phthaloyl-D L-phenylalanine. 

N-(tert-Butoxycarbonyl)-P-4-(methoxycarbonyl)phenyl]alanine methyl ester L-Phenylalanine, N-[(l,l-dimethylethoxy)carbonyl]-4-(methoxycarbonyl)-, methyl ester (160168-19-4)... 

N-[N-(benzyloxycarbonyl)-L-aspart-l-oyl-(L-leucyl-L-threonyl-N6-tosyl-L-lysine p-nitrobenzyl ester)-4-oyl]-N-[N-(benzyloxycarbonyl)-L-aspart-l-oyl-(L-leucyl-L-threonyl-N6-tosyl-L-lysyl-L-aspartic p-nitrobenzyl diester)-4-oyl]-N-[N-(benzyloxycarbonyl)-L-aspart-l-oyl-(L-phenylalanine methyl ester)-4-oyl]-... 

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