α-phenylglycine

Structural formula
Structural formula of α-phenylglycine without specifying the stereochemistry
General
Surname	α-phenylglycine
other names	2-phenylglycine 2-amino-2-phenylacetic acid PhG
Molecular formula	C 8 H 9 NO 2
Brief description	white crystalline powder
External identifiers / databases
CAS number 2835-06-5 ( DL -phenylglycine) 875-74-1 ( D -phenylglycine) 2935-35-5 ( L -phenylglycine) EC number 220-608-1 ECHA InfoCard 100.018.735 PubChem 3866 ChemSpider 3732 Wikidata Q15633805
properties
Molar mass	151.16 g mol −1
Physical state	firmly
Melting point	277 ° C (decomposition, D- phenylglycine)
solubility	poorly soluble in water ( D- phenylglycine, 3 g l −1 at 20 ° C)
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

α-Phenylglycine (often abbreviated but not clearly referred to as phenylglycine ) is a non-naturally occurring, non-proteinogenic α-aminocarboxylic acid .

Stereochemistry

α-Phenylglycine contains an asymmetrically substituted carbon atom, it is therefore a chiral compound . There are two mirror-image molecules ( enantiomers ) of α-phenylglycine, D -phenylglycine and L -phenylglycine.

Stereoisomers of α-phenylglycine
Surname	D -phenylglycine	L -phenylglycine
other names	( R ) -phenylglycine (-) - phenylglycine	( S ) -phenylglycine (+) - phenylglycine
Structural formula
CAS number	875-74-1	2935-35-5
	2835-06-5 (mixture of isomers)
EC number	212-876-3	220-909-8
	220-608-1 (mixture of isomers)
ECHA info card	100.011.706	100.019.009
	100.018.735 (mixture of isomers)
PubChem	70134	99291
	3866 (mixture of isomers)
Wikidata	Q423849	Q27225746
	Q15633805 (mixture of isomers)
Melting point	277 ° C
	290 or 255 ° C (racemate)

D -phenylglycine

D- phenylglycine [synonym: ( R ) -phenylglycine] is the economically more important isomer that is contained as a partial structure in the side chain of several semisynthetic β-lactam antibiotics , for example in ampicillin .

presentation

D- phenylglycine can be obtained by cleavage of the racemate DL -phenylglycine with the aid of D - camphor-10-sulfonic acid in the presence of acetic acid and salicylaldehyde . The yield in this process is 68% with an optical purity of 95.9%.

The enzymatic preparation of D -phenylglycine from phenylpyruvate succeeded in 2006. Phenylpyruvate is a direct precursor of L - phenylalanine . Therefore, an E. coli strain was used for the display , which was optimized for the production of L- phenylalanine on the basis of glucose . The conversion of the phenylpyruvate took place via mandelate and phenylglyoxylate in three stages. These were catalyzed by three enzymes [hydroxymandelate synthase (HmaS), hydroxymandelate oxidase (Hmo) and the stereoinverting hydroxyphenylglycine aminotransferase (HpgAT)]. The genes encoding these enzymes were from Amycolatopsis orientalis , Streptomyces coelicolor and Pseudomonas putida .

properties

D- phenylglycine is a colorless solid that decomposes at 305 ° C. The rotation value α of a 1 molar solution in 1 molar hydrochloric acid is -155 ° at 20 ° C. and a wavelength of 589 nm .

use

D- phenylglycine is an important side chain building block for the semi-synthetic production of β-lactam antibiotics such as cefalexin or ampicillin .

L -phenylglycine

The enantiomeric amino acid L- phenylglycine [synonym: ( S ) -α-phenylglycine] is only of secondary importance. L -phenylglycine is part of the streptogramin antibiotic pristinamycin or virginiamycin that of Streptomyces pristinaespiralis or Streptomyces virginiae are produced.

Individual evidence

1. ↑ ^{a b c d e} Data sheet D - (-) - 2-Phenylglycine, 99% from AlfaAesar, accessed on December 7, 2019 ( PDF )(JavaScript required) .
2. ↑ Data sheet D (-) - alpha-phenylglycine at Acros, accessed on December 25, 2019.
3. ↑ Entry on Phenylglycine. In: Römpp Online . Georg Thieme Verlag, accessed on January 17, 2016.
4. ↑ Chikara Hongo, Ryuzo Yoshioka, Masanori Tohyama, Shigeki Yamada, Ichiro Chibata: "Racemization of Optically Active Amino Acid Salts and an Approach to Asymmetric Transformation of DL-Amino Acids", in: Bull. Chim. Soc. Yep , 1983 , 56 , pp. 3744-3747; doi : 10.1246 / bcsj.56.3744 ; described in patent specification WO 1995023805 .
5. ↑ ^{a b} U. Müller, F. van Assema, M. Gunsior, S. Orf, S. Kremer, D. Schipper, A. Wagemans, CA Townsend, T. Sonke, R. Bovenberg, M. Wubbolts: "Metabolic engineering of the E. coli L-phenylalanine pathway for the production of D-phenylglycine (D-Phg) ", in: Metab Eng. , 2006 , 8 (3) , pp. 196-208; PMID 16466681 .
6. ↑ Data sheet D - (-) - α-Phenylglycine from Sigma-Aldrich , accessed on February 19, 2010 ( PDF ).
7. ↑ YJ Mast, W. Wohlleben, E. Schinko: Identification and functional characterization of phenylglycine biosynthetic genes involved in pristinamycin biosynthesis in Streptomyces pristinaespiralis. In: Journal of Biotechnology . Volume 155, Number 1, August 2011, pp. 63-67, ISSN  1873-4863 . doi : 10.1016 / j.jbiotec.2010.12.001 . PMID 21146568 .