DL-3- -alanine

DL-Alanine is the first amino acid which was synthesi2ed chemically (138). Glycine and DL-methionine have also been suppHed by this method (20). However, amino acids formed by the chemical method are racemic, and it is necessary to resolve the mixture to get the L- or D-form amino acid which is usually demanded. 

Chemical Production. Glyciae, DL-methionine, and dl-alanine ate produced by chemical synthesis. From 1964 to 1974, some glutamic acid was produced chemically (48). The synthetic amino acid with the largest production is DL-methionine from actoleia (see Acrolein and derivatives). The iadustrial production method is shown ia the foUowiag (210). 

In some cases, Bucherer s process is employed also, but strict control of reaction conditions is needed because the reactivity of formaldehyde is different from other aldehydes. DL-Alanine (212) is produced by either Strecker s or Bucherer s process from acetaldehyde. 

L-cysteine (derivatives) /5-chloro-DL-alanine + Na2S Cys desulfhydrase Enterobactor cloacae 193... 

D-alanine DL-alanine hydantoin D-hydantoinase + d-A- carbamylamino acid amidohydrolas Firth, crystallopoietes ... 

D-alanine (peptides) DL-alanine (peptide) amide(s) D-amino acid arninopeptidase Ochrobactrum anthropi, Bhodococcus erythropolis 174... 

D-cysteine (derivatives) 3-chloro-DL-alanine + iNaHS 3-chloro-D-Ala dehydrochlorinase or Pseudomonas putidaE. coli etc ... 

In Industrial Chemicals. Recendy, as some amino acids (eg, L-glutamic acid, L-lysine, glycine, DL-alanine, DL-methionine) have become less expensive chemical materials, they have been employed in various appHcation fields. Poly(amino acid)s are attracting attention as biodegradable polymers in connection with environmental protection (236). 

Glycine (hRf 20—25), DL-alanine (hRf 30 — 35), DL-valine hRf 45 — 50) and L-leucine (HRf 55—60) yielded red-violet chromatogram zones on a pale yellow background. The detection limits for these amino acids were 5 ng substance per... 

Other amino adds produced by wild strains indude L-valine, DL-alanine and L-proline. 

NITRO-, ETHYL ESTER, ( >], 65 Adipic acid [Hexanedioic acid], 70 DL-Alanine, jV-(tnfluoroacetyl)-, 125 Alcohols, primary, 40... 

C(,H,2CaN204 J6i27-40-Q see Calcium pantothenate DL-alanine ethyl ester hydrochloride (C5H12CINO2 677-27-6) see Pyridoxine (5)-alaninol... 

D-Alanine, systematic name, formula, and molecular weight, 2 555t dl-Alanine... 

HjCO ch3 1. Na[BH4] (4,2 Aquiv.)/ Kieselgel, CHCla/ (HjQjCH-OH (1 3,4) 20% 2 h 2. H3/Pd -C, H3C-OH ohne Druckh, 20°, 5 h 3. 2N HQ, 70% 5 h dl-J- ( 2-Methoxy-1-naphthyl )-2-nitro-propan-saure-methylester (Gl Reinigung durch Chromsi-togr.) + 3-(2-Methoxy-1-naphthyl ) -DL-alanin-methyl-ester8 (Oi) + 3-(2-Methoxy-1-naphthyl ) -DL-alanm-Hydro-chlorid (Zers.p. 241-245s) 75 r 75 3... 

Ahnlich Methode erhalt man auch u.a.1 aus 1I3C-CO-COOH -> DL-Alanin 50%... 

The disadvantage in using such symmetrical bislactim ethers is that half the chiral auxiliary ends up as part of the product molecule thus only half of the auxiliary can be recovered and reused. This drawback is avoided in the mixed bislactim ether prepared from a chiral auxiliary (L-valine) and a racemic amino acid (e.g., DL-alanine). Regiospecific deprotonation followed by diastereoselective alkylation leads to the required a-methyl amino acid ester (193) (83T2085) the de is >95%. In this method, the chiral auxiliary (L-valine) is recovered intact. (Scheme 59). 

Using the corresponding (6R) isomer (from D-valine and DL-alanine), alkylation with 2-chloro-3-methyl quinoxaline followed by further transformation has yielded an aldose reductase inhibitor in optically pure form (90T7745). 

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