2- Methyl-3-oxovaleric acid

Hydroxy-n-valeric acid is perhaps the most frequently observed urinary metabolite after methylcitrate and 3-hydroxypropionate, and 3-oxo-/r-valeric acid may also occur during severe ketosis. During non-ketotic periods, when propionyl-CoA accumulation still occurs, two molecules of this substrate may condense via the action of a j3-ketothiolase to form 2-methyl-3-oxovaleryl-CoA, resulting ultimately in the excretion of 2-methyl-3-hydroxyvaleric and 2-methyl-3-oxovaleric acids in the urine (Lehnert et ai, 1978 Truscott et al., 1979). The occurrence of these keto acids explains the presence of long-chain ketones in the urine, formed by decarboxylation in an analogous manner to the formation of acetone from acetoacetate (Fig. 11.6). 

Lehnert, W., Schuchmann, L., Urbdnek, R., Niederhoff, H. and Bohm, N. (1978), Excretion of 2-methyl-3-oxovaleric acid in propionic acidemia. Eur. J. Pediatr., 128, 197. 

Piperidines. A soln. of 5-phenyl-5-oxovaleric acid methylamide in benzene added with effective stirring to a soln. of ca. 300% excess LiAlH4 in ether, and refluxed ca. 6 hrs. l-methylamino-5-phenyl-5-pentanol (Y 82%) neutralized with 1 iV HBr, concentrated, dried by distillation with chloroform, treated with PBrg, and the product isolated the next day l-methyl-2-phenyl-piperidine (Y 80%). F, e. s. R. Luke and M. Cerny, Coll. Czech. Ghem. Commons. 2A, 1287 (1959). 

In 1941 Gakhokidze40 realized a different type of Grignard synthesis on a carbohydrate acid derivative. Methyl L-ery(liro-3,4,5-trimethoxy-2-oxovalerate (XXXII), was treated with one mole of methylmagnesium iodide to produce methyl 2-methyl-2-hydroxy-L-er /(firo-3,4,5-trimethoxy-valerate (XXXIII). The configuration of the second carbon atom in... 

C6H10O2 cis-3-methyl-2-pentenoic acid 19866-51-4 475.00 41.487 2 7908 C6H10O3 methyl 3-oxovalerate 30414-53-0 459.55 40.012 2... 

C8H1402 1-methyl-1-cyclohexanecarboxylic acid 1123-26-7 507,15 44.572 1,2 14724 C8H1405 methyl 4,4-dimethoxy-3-oxovalerate 62759-83-5 473.15 2... 

Methyl-2-oxopentanoate =iL-leucine 3-Methyl-2-oxobutanoate =iL-valine 3-Methyl-2-oxovalerate =iL-isoleucine ) Branched-chain-amino-acid aminotransferase L-Glutamate... 

Fig. 11.2 Total ion current chromatogram (Varian MAT 44 GC-MS) of organic acids extracted using ethyl acetate and diethyl ether from the urine of a patient with propionic acidaemia and separated as their trimethylsilyl derivatives on a 25 m SE-54 WCOT capillary column using temperature programming from 70°C to 220°C at 4 C min Peak identifications are 1, lactate 2, 3-hydroxypropionate 3, 3-hydroxybutyrate 4, 2-methyl-3-hydroxybutyrate 5, 3-hydroxyisovalerate 6, 3-hydroxy- -valerate 7, aceto-acetate 8 and 9, 2-methyl-3-hydroxyvalerate 10, 3-oxovalerate 11, 2-methyl-3-oxo-valerate (isomer 1) 12,2-methylacetoacetate 13,2-methyl-3-oxovalerate (isomer 2) 14 propionylglycine 15, glutarate 16, adipate 17, 5-hydroxymethyl-2-furoate 18, 2-hydroxyglutarate 19,3-hydroxy-3-methylglutarate 20,4-hydroxyphenylacetate 21 and 22, methylcitrate 23,4-hydroxyphenyl-lactate 24, palmitate. (Redrawn with modifications from Truscott et al., 1979)...

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