Methyl pentanoate

Hydroxy 2 methyl pentanoic acid (60% from 2 pentanone)... 

In its manufacture, methyl ethyl ketone is condensed with ethylcyanoacetate to give ethyl-2-cyano-3-methyl-2-pentenoate. That, in turn, adds HCN to give ethyl-2,3-dicyano-3-methyl-pentanoate. Saponification and decarboxylation gives 2-methyl-2-ethyl succinonitrile. Heating with aqueous NH3 gives the diamide which loses NHj and cyclizes to ethosuximide. 

Benzyl cyanide is first reacted with 2-butylbromide in the presence of sodium amide to give 2-phenyl-3-methylvaleronitrile which is hydrolyzed by sulfuric acid to give 3-methyl-2-phenyl-pentanoic acid. 24 g of 2-phenyl-3-methyl-pentanoic acid are heated for one hour at 175° to 185°C with 30 g of 2-diethylaminoethanol and 0.5 g of sodium methylate. The excess diethyl-aminoethanol is removed in vacuo, the residue is dissolved in 300 cc of 2 N-acetic acid, the acid solution is shaken with ether and made alkaline with concentrated potassium carbonate solution and ice. The ether solution Is washed with water, dried with sodium sulfate and evaporated. The residue is distilled under high vacuum, yielding 20 to 21 g of the basic ester (60% of the theoretical) is obtained, the ester boiling at 98° to 100°C at a pressure of 0.03 mm. The hydrochloride of the ester melts at 112° to 113°C and the methobromide at 100° to 101°C. 

R+ is intense in methyl acetate, methyl propionate, methyl butyrate, and methyl pentanoate. 

Isobutyl acetate t-Butyl acetate Propyl propionate Ethyl butyrate Ethyl isotxityrale Methyl pentanoate Methyl pivalate Paraldehyde... 

Methylpentanenitrile Methyl pentanoate 2-Methylpentanoic acid 2-Methyl- 1-pentanol... 

Substituted cyclopropanols were also obtained, albeit in moderate yields, upon reaction of esters such as methyl pentanoate with l,4-bis(bromomagnesium)butane (38) in the presence of titanium tetraisopropoxide. This corroborates the formation of a titanacy-clopropane—ethylene complex 40 from an initially formed titanacyclopentane derivative 39 (Scheme 11.12) [103], Apparently, an ester molecule readily displaces the ethylene ligand from 40, and a subsequent insertion of the carbonyl group into the Ti—C bond, a formal [2S + 2J cycloaddition, leads to the oxatitanacyclopentane 42, the precursor to 1-butylcyclopropanol (43). 

The one-step condensation to convert 2-butanone, ethyl cyano-acetate, and hydrocyanic acid to ethyl 2,3-dicyano-3-methyl-pentanoate is a modification of the procedure described by Smith and Horowitz 6 in which pyridine acetate was employed as the catalyst. Higson and Thorp 6 employed a two-step procedure in which butanone was converted to its cyanohydrin, which in turn was condensed with ethyl cyanoacetate. 

Leucine (Leu or L) ((A)-2-amino-4-methyl-pentanoic acid) is a neutral, aliphatic amino acid with the formula HOOCCH(NH2)CH2CH(CH3)2 and with a hydrocarbon side chain. Leu is classified as a hydrophobic (nonpolar) amino acid. ... 

Ethyl N-benzylcarbamate, 35, 91 Ethyl 3-benzyl 2 cyano 3 methyl-pentanoate, 35, 7 Ethyl bromide, 34, 58, 36, 87 Ethyl a-bromobutyrate, 37, 44 Ethyl a bromopropionate, 35, 17, 37, 38... 

An independent proof of this finding was recently obtained by Ciardelli, Benedetti, Pieroni and Pino (23, 24) who prepared an atactic poly-(S)-4-xnethyl-1-hexene having [M] >5 = +190 from a poly-(S)-4-methyl-l-hexyne having an optical purity of about 89.5% as demonstrated by the optical purity of (S)-3-methyl-pentanoic acid obtained by ozonization of the unsaturated polymer. The rotatory power of the polymer thus prepared is very near to the rotatory power of the non crystallizable poly-(S)-4-methyl-l-hexene obtained from a monomer having a 93% optical purity (see Table 8). 

Syn. i, 68) (Note 5). The solution is distilled with the separator, and the aqueous portion is returned to the distilling flask. This operation is continued until practically all of the organic acid has been driven over. This requires from ten to fifteen hours. At the end, about 100 cc. of water is collected in the separator and extracted with ether in order to remove the dissolved acid (Note 6). The ether is distilled and the crude acid is mixed with an equal volume of dry benzene (Note 7) and distilled through a fractionating column (Org. Syn. i, 40). Benzene and water distil first and then the 3-methyl pentanoic acid distils at 193-i96°/743 mm. The yield is 66-69 g- (62—65 per cent of the theoretical amount) (Note 8). 

The ethyl sec,-butylmalonate was prepared from sec-butyl bromide and malonic ester according to the general method described in Org. Syn. 4, n. The yield of ester boiling at i24-i32°/28 mm. was 80-81 per cent of the theoretical amount. The yields of 3-methyl pentanoic acid given in this procedure were obtained with this grade of ester. 

It is necessary that all of the alcohol be eliminated after the saponification. If some is allowed to remain, ethyl 3-methyl pentanoate is formed and a considerable amount of low-boiling material is present in the final product. 

Methyl pentanoic add has always been prepared by heating sec.-butyl malonic acid.1... 

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