A- -2-Methylbutyric acid

Draw the structures of the following carboxylic (a) a-methylbutyric acid (c) 4-aminopentanoic acid (e) /ra/7.v-2-mclhylcyclohcxanccar boxy lie acid... 

O-methyl groups a modified Kuhn-Roth oxidation gave a mixture of acetic and a-methylbutyric acids. These results allowed the following partial structure to be proposed for echitamine chloride and base C (76) ... 

Problem 16.61 Prepare a-methylbutyric acid from ethanol. ... 

Oxidation with lead dioxide in 5% phosphoric acid yielded acetaldehyde and formaldehyde. Catalytic reduction in the presence of platinum resulted in the absorption of 1.5 mole equivalents of hydrogen and the isolation, by its steam volatility, of nearly 0.6 mole of a-methylbutyric acid. The carbon skeleton of sarracinic acid was thus determined, and the accompanying hydrogenolysis (some nonvolatile acid was also obtained) established that the double bond and hydroxyl constituted an allylic alcohol moiety. Since further data (spectroscopic data would be especially valuable) were not available, Danilova and Kuzovkov (127) were limited to the conclusion that sarracinic acid could be represented by one of three possible structures (CLXIa-c) ... 

Beilstein Handbook Reference) Active valeric acid AI3-24202 BRN 1098537 Butanoic acid, 2-methyl- Butyric acid, 2-methyl- EINECS 204-145-2 EINECS 209-982-7 Ethylmethylacetic acid FEMA No. 2695 (1)-2-Methylbutyric acid a-Methylbutyric acid 2-Methybutyric acid 2-ttethylbutanoic acid Methylethyl-acetic acid NSC 7304 Valeric acid, active. 

The structural feature of these compounds is the hexahydronaphthalene ring system which is functionalized with a-methylbutyric acid ester and a P-hydroxy-8-lactone linked by an ethylene bridge. The p-hydroxy-8-lactone portion of these compounds can be easily opened, and it is converted to the 3, 5 -dihydroxyheptanoic acid [22]. This hydroxy acid portion of their structures, which resembles the HMG portion of the HMG-CoA, is responsible for the activity, and it is known to interact competitively with the HMG binding domain of the enzyme active site [37]. 

A systematic investigation of structure-activity relationship (SAR) has shown that the introduction of an additional aliphatic group on the carbon a to the carbonyl group in a-methylbutyric acid ester linkage of lovastatin increases its potency. This result has led to the synthesis of simvastatin (15) and this modification increased the intrinsic inhibitory activity of lovastatin by 2.5 times [38]. 

In agreement with the derived structure hexahydrodeazanorvobasine, upon oxidation with chromic acid, formed a-methylbutyric acid in addition to acetic and propionic acids. Also in complete harmony with the chosen structure was the formation of trideuterio-16-epivobasine by a base-catalyzed deuteration (MeOD/MeONa) of vobasine followed by reprotonation of the indole nitrogen. 

On hydrolysis with methanolic potash protoveratridine yields the alkamine germine, C27H430gN, and d-(—)-a-methylbutyric acid, [ ]d — 23.1° (water) (51). 

Alkaline hydrolysis of germerine yields the alkamine germine, D-(—)-o-methylbutyric acid, [ ]d — 22°, —25 (water), and (-l-)-o-hydroxy-a-methylbutyric acid, m.p. 72-73°, [a]o + 4.4° (water). With baryta at 40° it yields protoveratridine on partial hydrolysis and ultimately germine (19, 51). 

PROPERTIES AND DERIVATIVES. Germidine, Cj4H6 OioN, is dimorphic and melts at 198-200° or 230-231° (dec.) (dil. ethanol) [a]o + 13 (chloroform), —11° (pyridine) thiocyanate, m.p. 242-244 (dec.) (dil. methanol). Alkaline hydrolysis of germidine gave rise to germine and a mixture of acetic and d-(—)-a-methylbutyric acid, which were obtained in the form of their p-phenylphenacyl esters (19). 

To 10 mL benzene solution containing 0.48 g a-methylbutyric acid (4.7 mmol) was added 2.0 g lead tetraacetate (4.5 mmol). The mixture was stirred at room temperature until homogeneous. Then 0.196 g LiCl (4.5 mmol) was added, and the mixture was immediately flushed with nitrogen to remove oxygen. The surface of the salt at room temperature rapidly achieved a yellow coloration with LiCl. The mixture was placed in a constant-temperature oil bath (81 0.3°C), and the rate of gas evolution was followed volumetrically. The induction period was very short and gas evolution followed apace. The completion of the reaction resulted in a clear colorless solution and a colorless amorphous solid, and the solution was decanted and extracted with dilute aqueous perchloric acid, followed by a Na2C03 wash. The organic layer was dried over Na2S04. About 89% iec-butyl chloride was yielded from this reaction. 

Methyl butyric acid. See Isovaleric acid, a-Methylbutyric acid. See 2-Methylbutyric acid P-Methylbutyric acid. See Isovaleric acid DL-2-Methylbutyric acid CAS 600-07-7 EINECS/ELINCS 209-982-7 UN 3265... 

Juloerotine, C18H24O3N2 (mp 109° [a]D —9° in CHCI3, -50° in MeOH) was first reported by Anastasi (135) but its nonbasic nature and its structure were only determined recently 136). Extensive spectral studies indicated the nature of the functional groups and complete acid hydrolysis resulted in (8-phenethylamine, (+ )-a-methylbutyric acid, and L-( + )-glutamic acid. These fragments show that juloerotine is LIV. Julocroton subpannosus Muell. Arg. and J. camporum ( ) also contain juloerotine. 

Base Z, CjaHj OaN. This name was provisionally applied to a syrupy base which yielded a crystalline oxalate, Bg. HgCg04, m.p. 296-7°, a hydrobromide m.p. 219-20° [a]f ° + 2-9° (c = 6 HgO), a methiodide m.p. 801°, and a picrate m.p. 172°. On hydrolysis it furnished nortropine (tropigenine, p. 75) and a liquid acid, eventually shown to be a mixture of isovaleric and d-a-methylbutyric acids. Base Z is therefore a mixture of isovalerylwortropeine (which has been named poroidine) and d-a-methyl-butyrylnortropeine (isoporoidine). Separation has not been effected but the two components have been synthesised and described. 

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