A-Hydroxybutyric acid

DL-a-amiaobutyric acid DL-a-hydroxybutyric acid DL-a-bromobutyric acid 15.7 184... 

L-(-)-7-Ami no-a-hydroxybutyric Acid N-hydroxysuccinim ide 6 -Monobenzyloxy[Pg.58]

Preparation of L-(-)-y-Benzyloxycarbonylamino-a-Hydroxybutyric Acid L-(-)-7-amino-o-hydroxybutyric acid (7.4 g, 0,062 mol) was added to a solution of 5.2 grams (0.13 mol) of sodium hydroxide in 50 ml of water. To the stirred soiution was added dropwise at 0 -5°C over a period of 0.5 hour, 11.7 grams (0.06B mol) of carbobenzoxy chloride and the mixture was stirred for another hour at the same temperature. The reaction mixture was washed with 50 ml of ether, adjusted to pH 2 with dilute hydrochloric acid and extracted with four BO ml portions of ether. The ethereai extracts were combined, washed with a small amount of saturated sodium chloride solution, dried with anhydrous sodium sulfate and filtered. The filtrate was evaporated in vacuo and the resulting residue was crystallized from benzene to give 11.6 grams (74%) of colorless plates MP 78.5° to 79.5°C. 

Dantrolene sodium L-(-) - y-Amino-a-hydroxybutyric acid Amikacin... 

Isolated polynucleotide clusters from Rhodococcus opacus which encode four polypeptides possessing the activities of a NHase (a and /3 subunits), an auxiliary protein P15K that activates the NHase, and a cobalt transporter protein were expressed in Escherichia coli DSM 14459 cells [34]. Methionine nitrile was added continuously to a suspension of the transformant cells (5.6% w/v of wet cells) in phosphate buffer (50 mM, pH 7.5) at 20 °C, at a rate where the nitrile concentration did not exceed 15 g L 1 while maintaining the pH constant at 7.5. After 320 min, the nitrile was completely converted into amide, corresponding to a final product concentration of 176 gL1.4-Methylthio-a-hydroxybutyramide is readily hydrolyzed with calcium hydroxide, where the calcium salt of 4-methylthio-a-hydroxybutyric acid (MHA) can be directly used as a nutritional supplement in animal feed as an alternative to methionine or MHA. 

The wash water of the above CG-50 column was adjusted to pH 7.0 and applied on a column of Amberlite IR-120 (H+ form, 30 ml). The column was washed with water and then eluted with 1 N ammonium hydroxide. Ninhydrin-positive fractions were combined, treated with active carbon and neutralized with IRC-50 resin (H+ form). The solution was concentrated to a small volume, treated with ethanol, and kept in the cold overnight to yield 160 mg (75%) of amino-a-hydroxybutyric acid as colorless needles which melted at 217°C-218°C. [a]D23= -30.3° (c=1.0%, H20). 

Isobutylene Glycol and a-Hydroxybutyric Acid.37 To 16.3 g. of a-hydroxyisobutyraldehyde is added dropwise 40 cc. of 10% aqueous sodium hydroxide. The resulting solution is warmed on the water bath to complete the reaction, cooled, and extracted with ether. Bemoval of the ether leaves the glycol as a honey-colored oil which is purified by distillation (b.p. 177-179°). 

Pterorhodine (113b)181 and drosopterin (133)182 are naturally occurring dimeric pteridines the former was synthesized from xanthopterin and acetone or acetaldehyde in the presence of ammonium sulfate or hydrogen peroxide,136 and the latter from 7,8-dihydropterin and j8-keto-a-hydroxybutyric acid.182b... 

The cyanohydrin synthesis of a-hydroxy acids is very often carried out without isolation or purification of the cyanohydrins. The various techniques for the preparation of the cyanohydrins are discussed elsewhere (method 390). Hydrolysis to the a-hydroxy acids is usually effected by heating with concentrated hydrochloric acid. Excellent directions are given for mandelic acid (52% over-all from benzaldehyde), a-methyl-a-hydroxybutyric acid (65% from methyl ethyl ketone), and eighteen dialkyl- and alkylphenyl-glycolic acids (60-80%). Sodium hydroxide solution is used in the preparation of /S-hydroxypropionic acid from the /S-hydroxy nitrile (80%). ... 

The enzyme resistance shown by BB-K8 is thought to be due to a blocking effect caused by the a-hydroxybutyric acid side chain. This appears to be a promising area of research but the toxicity problems associated with aminoglycoside antibiotics have still to be overcome. 

In addition to tartrate, a-hydroxyisobutyrate can be utilized as the complexing anion. It was employed by Cassidy et al. [144] for the separation of lanthanides. In comparison to tartrate, no particular advantages are revealed in the separation of divalent metal ions. Fig. 3-150 shows a separation of the seven heaviest lanthanides with an eluent mixture of ethylenediamine and a-hydroxybutyric acid. The pronounced tailing effects observed under isocratic conditions for late eluting ions are unsatisfactory. 

Fig. 3-150. Separation of the seven heaviest lanthanides with an eluent mixture of ethy-lenediamine and a-hydroxyisobutyric acid. -Separator column see Fig. 3-149 eluent 0.004 mol/L ethylenediamine + 0.003 mol/L a-hydroxybutyric acid, pH 4.5 flow rate 0.85 mL/min detection direct conductivity injection volume 100 pL solute concentrations 10 ppm each (taken from [148]).

Smith, A. J., and Strang, L. B., An inborn error of metabolism with the urinary excretion of a-hydroxybutyric acid and phenyl-pyruvic acid. Arch. Dis. Childhood 33, 109-113 (1958). 

Alimet Butanoic acid, 2-hydroxy-4-(methylthio)- Butyric acid, 2-hydroxy-4-(methyithio)- EINECS 209-523-0 -/-(Methylthiol-a-hydroxybutyric acid a-Hydroxy-y-(methylmercapto)butyric acid a-Hydroxy-y-(methylthio)butyric acid 2-Hydroxy-4-(methylthio)butyric acid 2-Hydroxy-4-(methylthio)butanoic acid HSDB 5700 Methionine hydroxy analog MHA MHA acid MHA-FA. Used as a feed additive for livestock, especially poultry. Monsanto Co. 

Write equations for reactions by which (a) /3-hydroxycaproic acid may be converted into amylene, (h) propronic aldehyde into a-hydroxybutyric acid, (c) lactic acid into aa-dibromopropionic acid. 

Preparation of N-Hydroxysuccinimide Ester of L-(-j-y-Bemyloxycarbonylamino-a-Hydroxy-butyric Acid A solution of 10.6 grams (0.042 mol) of L-(-)-7-benzyloxycarbonylamino-a-hydroxybutyric acid and 4.8 grams (0.042 mol) of N-hydroxysuccinimide in 200 ml of... 

Preparation of 1-[L-(-)-y-Benzyloxycarbonylamino-ot-Hydroxybutyryl]-6 -Carbobemoxy-kanamycin A A solution of 1.6 grams (4.6 mmol) of L-(-)-7-benzyloxycarbonylamino-a-hydroxybutyric acid in 40 ml of ethylene glycol dimethyl ether (DME) was added drop-wise to a stirred solution of 2.6 grams (4.2 mmol) of 6 -monobenzyloxycarbonylkana-mycin A in 40 ml of 50% aqueous ethylene glycol dimethyl ether and the mixture was Stirred overnight. The reaction mixture was evaporated under reduced pressure to give a brown residue 1-[L-(-)-7-benzyloxycarbonylamino-cr-hydroxybutyryl]-6 -carbobenzoxykana-mycin A which was used for the next reaction without further purification. 

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