Methyl 4-amino-2-hydroxybutyrate

For instance, RNi modified with an optically active amino acid or hydroxy acid hydrogenates methyl acetoacetate (MAA) to produce optically active methyl 3-hydroxybutyrate (MHB) as shown in Fig. 1. 

Figure 20.20 Pathways of branched-chain amino acid metabolism. A, B, C, D, E, and F indicate defects in valinemia, maple syrup urine disease, isovaleric acidemia, /3-hydroxyisovaleric aciduria, a-methyl-j3-hydroxybutyric aciduria, and methylmalonic aciduria, respectively.

This chapter describes the case reports of these enzyme deficiencies and the underlying biochemistry of the disorders and their associations. It is not the intention to discuss keto acidosis associated with other diseases, for example juvenile diabetes, or ketogenesis and its control which are reviewed elsewhere (Wildenhoff, 1975, 1977 McGarry and Foster, 1976 Halperin, 1977). In addition to the common occurrence of 3-hydroxybutyrate and acetoacetate in body fluids of patients with keto acidosis, secondary organic acids have been observed in urine, including adipic and suberic acids (Pettersen et aL, 1972), 3-hydroxyisovaleric acid (Landaas, 1974), 3-hydroxyisobutyric acid and 2-methyl-3-hydroxybutyric acid (Landaas, 1975). The dicarboxylic acids occur as a result of initial co-oxidation of accumulating long-chain fatty acids followed by )8-oxidation (Pettersen, 1972), and metabolites of the branched-chain amino acids occur because of inhibition of their metabolic pathways by 3-hydroxybutyrate and acetoacetate (Landaas and Jakobs, 1977). 

Amide 26a can be converted directly to methyl ester 27 upon treatment with 3% methanol— HCl. This ester is used as a starting point for the synthesis of 7-amino-jS-hydroxybutyric acid (32), a GABA derivative of great biological and synthetic importance (Scheme 3) [30]. 

Mild hydrolysis of butirosin A and B with acid slowly liberated n-xylose and n-ribose, respectively. Hydrolysis with concentrated acid gave neamine, neosamine C, 2-deoxystreptamine, and a novel amino acid, 4-amino-3,4-dideoxy-L-gtycero-tetronic acid [(S)-( —)-4-amino-2-hydroxybutyric acid] (53). Treatment of the methyl ester of this amino... 

Ethyl p-hydroxybutyrate Ethyl DL-3-hydroxybutyrate. See Ethyl 3-hydroxybutyrate Ethyl hydroxydiphenylacetate Ethyl 2-hydroxy-2,2-diphenylacetate Ethyl a-hydroxydiphenylacetate. See Methyl benzilate 2-(N-Ethyl-N-2-hydroxyethylamino) ethanol. See N-Ethyidiethanolamine 2-[[4-[Ethyl (2-hydroxyethyl) amino] phenyl] azo]-6-methoxy-3-methylbenzothiazolium methyl sulfate. See Basic blue 41 Ethyl (P-hydroxyethyl) aniline N-Ethyl-N-(2-hydroxyethyl) aniline. See Phenylethylethanolamine Ethyl hydroxyethyl cellulose CAS 9004-58-4 INS467... 

A soln. of N-tosyl-L-methionine in a mixture of methyl iodide, acetic acid, and 8Q% formic acid allowed to stand 10 hrs. at room temp, in the dark, coned, below 40° under reduced pressure, the resulting oil triturated with dry ether, dissolved in N NaOH-soln., stirred and heated 3 hrs. at 90°, while the pH is kept at 6-7 by addition of more N NaOH, and the intermediate N-tosyl-a-amino-7-hydroxybutyric acid treated with N HCl at pH 2-3 -> N-tosyl-a-amino-y-butyro-lactone. Y 92%. F. e. s. H. Sugano and M. Miyoshi, Bull. Chem. Soc. Japan 46, 669 (1973). 

Hydroxy-a-amino-acids are available by reduction and hydrolysis of the corresponding jS-keto-esters, obtained from methyl isocyanoacetate and acyl halides via oxazole-4-carboxylate intermediates. ° A synthesis of L-y-amino-/3-hydroxybutyric acid has been reported in which the key step is a dehydration of L-a-hydroxysuccinamic acid to the corresponding y-cyano-acid, presumably via a y-iminobutyrolactone. ° This could prove to be a general route to (3- and y-cyano-carboxylic acids. 

---