Valeric acid, 4-Methyl

C) dl-Isoleucine.—One hundred and fifty grams (0.77 mole) of a-bromo-/3-methyl valeric acid is added to 645 cc. of technical ammonium hydroxide (sp. gr. 0.90) in a 1.5-I. round-bottomed flask. A stopper is wired in and the flask allowed to stand at room temperature for a week (Note 9). The stopper is removed and the mixture heated on a steam cone overnight to remove ammonia. The aqueous solution is concentrated under reduced pressure until bumping becomes violent (about 300 cc.). The mixture is then cooled to 150 and the crystals collected on a filter. The crystals are washed with 40 cc. of alcohol and dried. The filtrate is again concentrated to about 150 cc. and a second crop of crystals obtained. This second crop is washed with 25 cc. of water and then with 25 cc. of 95 per cent alcohol. The yield of crude product is 65 g. 

Diastereoisomers. Whereas compounds with one chiral center exist as an enantiomorphic pair, molecules with two or more chiral centers also exist as diastereoisomers (diastereomers). These are pairs of isomers with an opposite configuration at one or more of the chiral centers, but which are not complete mirror images of each other. An example is L-threonine which has the 2S, 3R configuration. The diastereoisomer with the 2S, 3S configuration is known as i-a//o-threonine. L-isoleucine, whose side chain is -CH(CH3) CH2CH3, has the 2S, 3R configuration. It can be called 2(S)-amino-3(R)-methyl-valeric acid but the simpler name L-isoleucine implies the correct configuration at both chiral centers. 

This is a general method for preparing a-bromo acids. By using exactly analogous directions -bromo- -caproic acid may be obtained in 65-70 per cent yields from w-butylmalonic ester a-bromo-isocaproic acid in 65-70 per cent yields from isobutylmalonic ester and a-bromo-/3-methyl valeric acid in 75-80 per cent yields from sec.-butylmalonic ester. 

SYNS a-AMINOISOCAPROIC ACID 2-AMINO-4-METHYLPENTANOIC ACID O-AMINO-y-METHYL-VALERIC ACID 2-AMINO-4-METHYLVALERIC ACID 1.2-AMINO-4-METHYLVALERIC ACID LEUCIN (GERMAN) LEUCINE NORVAUNE, 4-METHYL- VALERIC ACID, 2-AMINO-4-METHYL-... 

Leucine. Leu (1UPAC abbrev ) 2-amino-4-methyl valeric acid a -aminoisocaproic acid 2 -amino -4-methyl -pentanoic acid, C4H13NO, mol wt 131.17. C 54.94%, H 9.99%, N 10,67%, O 24.40%, (CH3)JCHCH2CH(NHi)-COOH. An amino acid classified as essential for maintaining growth in rats. Essential component in human nutrition, not synthesized by the human body. so]n from gluten, casein, keratin Barnett, J. Blot Chem. 108, 543 (1933) U.S. pat. 2,009,868 by electrical transport from blood-corpuscle paste Cox et at, J. Biot Chem. 81,755(1929). Purification and separation from methionine Fox, Science 84, 63... 

AI3-08899 a-aminoisocaproic acid (S)-2-Amino-4-methylpentanoic acid 2-Amino-4-methylpentanoic xid (L) 2-Amino-4-methylpentanoic acid, (S)- a-amino-y-methylvaleric acid (S)-2-Amino- methylvaleric acid 2-amino-4-methyl-valeric acid 2-Amino-... 

Fig. 3.22. GC separation of keto and hydroxy acids from the urine of a patient with maple syrup urine disease. Top chromatogram, the patient before dietary treatment middle chromatogram, the same patient after two days on a diet bottom chromatogram, a mixture of reference compounds. Peaks 1, lactic acid 2, 2-hydroxyisobutyric acid 3, 2-hydroxybutyric acid 4, pyruvic acid 5, 3-hydroxyisobutyric acid 6, 3-hydroxybutyric acid 7, 2-hydroxyisovaleric acid 8, 2-ketobutyric acid 9, malonic acid (internal standard) 10, 2-methyl-3-hydroxybutyric acid 11, 2-hydroxy-n-valeric acid 12. methylmalonic acid 13, 3-hydroxyisovaleric acid 14a and b, 2-ketoisovaleric acid IS, acetoacetic add 16, 2-hydroxyisocaproic acid 17, 2-hydroxy-3-methylvaleric acid 18a, L-2-keto-3-methylvaleric add 18b, D-2-keto-3-methyl-valeric acid 19, 2-ketoisocaproic acid. Reproduced from [386],...

Pentanoic acid, 2-methyl- 2-methyl valeric acid -F -F... 

Allen, T.E. and A.J. Manson The analysis of 3-methyl-valeric acid in tobacco by HPLC 48th Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 48, Paper No. 9, 1994, p. 28. 

CAS 73-32-5 EINECS/ELINCS 200-798-2 Synonyms Acetic acid, amino-s-butyl- 2-Amino-3-methylpentanoic acid L-2-Amino-3-methylpentanoic acid 2-Amino-3-methylvaleric acid a-Amino-p-methylvaleric acid Isoleucine (INCI) Norvaline, 3-methyl- Valeric acid, 2-amino-3-methyl Classification A natural protein amino acid Definition Commercial prod, is the naturally occurring L(+)-enantiomer Empirical C6H13NO2... 

Synonyms Isocaproic acid Isohexanoic acid 4-Methyl valeric acid... 

MethylbutanoI 2-Methylbutanal a-Oxo-j8-methyl valeric acid Isoleucine... 

Methyl butyric acid Isovaleric acid -h trimethyl acetic acid a-Methyl valeric acid Cg-Acids... 

Pimelic acid, a-methyl valeric acid Suberic acid, methyl hexanoic acid Decane-l,10-dicarboxylic acid Dodecane-1,12-dicarboxylic add Tetradecane-l,14-dicarboxylic acid... 

Several alkyl-branched fatty acids were found to be powerful and characteristic food flavors. 2-Methylbutyric acid is an important constituent of the aroma of cranberry Vaccinium vitis-idaea L.) (77). 3-Methyl-valeric acid and isovaleric acid were identified in tobacco leaves and found to contribute to the distinct sensory properties of Turkish tobacco smoke 590). Isovaleric acid, which has the lowest flavor threshold (0.7 ppm) 522) of all saturated fatty acids, is regarded as an essential flavor component of Limburger cheese (575). ( )-3-Methyl-2-hexenoic acid was recognized as the malodorous component of schizophrenics sweat (579). The undesirable odor of mutton can be attributed to branched-chain and unsaturated fatty acids having 8 to 10 carbon atoms. The 4-methyl-branched acids and in particular 4-methyloctanoic and 4-methyl-... 

Tavormina, P. a., and M. H. Gibbs The metabolism of p, y-dihydroxy-j5-methyl valeric acid by liver homogenates. J. Amer. chem. Soc. 78, 6210 (1956). 

Following the ketol condensation to yield a-acetolactate and a-aceto-a-hydroxybutyrate the question arises as to whether the pinacol rearrangement occurs first to form a-keto-jS-hydroxyisovaleric acid and a-keto-i9-hydroxy- 8-methylvaleric acid (Fig. 7, III), or whether there is prior reduction. The evidence favoring pinacol rearrangement followed by reduction of the a-keto- 3-hydroxy acids is that enzymes have been found in Neurospora and E. coli which catalyze the reduction of synthetically prepared a-keto-(8-hydroxyisovaleric acid and a-keto-j8-hydroxy-/3-methyl-valeric acid to the corresponding a,/8-dihydroxy acids (166, 167). 

Truscott, R. J.W., Pullin, C.J., Halpern, B., Hammond, J., Haan, E. andDanks, D.M. (1979), The identification of 3-keto-2-methylvaleric acid and 3-hydroxy-2-methyl-valeric acid in a patient with propionic acidemia. Biomed. Mass Spectrom., 6,294. 

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