Acid Isovaleric

Isovaleric acid, Me2CHCH2COOH, is a colourless liquid with the unpleasant odour of valerian, b.p. 177 "C. Occurs in the roots of valerian and angelica together with an optically active form of methylethylethanoic acid. Prepared by oxidation of isoamyl alcohol. A mixture of acids similar to that obtained from valerian roots is prepared by oxidation of fusel oil. 

IsoValeric acid. Prepare dilute sulphuric acid by adding 140 ml. of concentrated sulphuric acid cautiously and with stirring to 85 ml. of water cool and add 80 g. (99 ml.) of redistilled woamyl alcohol. Place a solution of 200 g. of crystallised sodium dicliromate in 400 ml. of water in a 1-litre (or 1-5 litre) round-bottomed flask and attach an efficient reflux condenser. Add the sulphuric acid solution of the isoamyl alcohol in amaU portions through the top of the condenser shake the apparatus vigorously after each addition. No heating is required as the heat of the reaction will suffice to keep the mixture hot. It is important to shake the flask well immediately after each addition and not to add a further portion of alcohol until the previous one has reacted if the reaction should become violent, immerse the flask momentarily in ice water. The addition occupies 2-2-5 hours. When all the isoamyl alcohol has been introduced, reflux the mixture gently for 30 minutes, and then allow to cool. Arrange the flask for distillation (compare Fig. II, 13, 3, but with the thermometer omitted) and collect about 350 ml. of distillate. The latter consists of a mixture of water, isovaleric acid and isoamyl isovalerate. Add 30 g. of potassium not sodium) hydroxide pellets to the distillate and shake until dissolved. Transfer to a separatory funnel and remove the upper layer of ester (16 g.). Treat the aqueous layer contained in a beaker with 30 ml. of dilute sulphuric acid (1 1 by volume) and extract the liberated isovaleric acid with two... 

Fig. 8. Stmcture of (a) valinomycin and (J3) and enniatins and beauvericin. Hov = a-hydroxy-isovaleric acid and Lac = lactic acid. The /V-methylamino acid for enniatin A is isoleucine enniatin B, valine enniatin C, leucine and beauvericin, phenylalanine.

Isovaleric acid [502-74-2] M 102.1, b 176.5 /762mm, 4.77. Dried with Na2S04, then fractionally distd. 

In 1931 Ing pointed out that formula (II) and (III) do not contain methyl or potential methyl groups in j ositions 6 and 8 which they occupy in cytisoline. Further, a partially reduced quinoline ought to oxidise easily to a benzenecarboxylic acid and so far the only simple oxidation, products recorded from cytisine were ammonia, oxalic acid and isovaleric acid. Distillation of cytisine with zinc dust or soda-lime yields pyrrole and pyridine, but no quinoline. On these grounds Ing suggested that cytisine should be formulated without a quinoline nucleus, and that the reactions which indicate the presence of an aromatic nucleus in the alkaloid can be accounted for by an a-pyridone ring. This a-pyridone nucleus can... 

The hyoscine system occurs alone in certain northern Duboisia myo-poroides, and forms scopine, -tropine, dihydroxytropane and, in Datura meieloides, teloidine. Of these amino-alcohols, all the scopine is esterified by tropic acid and the minor bases by tiglic, methylbutyric or isovaleric acid, which contain the isoprene skeleton and are presumed to arise from that source. 

Cypresaeoe yields, nn ovidaiion with nitric acid, an amoi plioos yellow product aud au aoid possessing the odour of isovaleric acid the amorphous product dissolve.- in aitalies with a red coloration. 

It yields, on oxidation with nitric acid, an acid having the odour of isovaleric acid. It is probably trycyclic. 

C7H4N2O2S 2719-30-4) see Astemizole isovaleraldehyde (C5H10O 590-86-3) sec Bulizide isovaleric acid... 

To obtain a maximum yield of the acid it is necessary to hydrolyse the by-product, tsoamyl isovalerate this is most economically effected with methyl alcoholic sodium hydroxide. Place a mixture of 20 g. of sodium hydroxide pellets, 26 ml. of water and 226 ml. of methyl alcohol in a 500 ml. round-bottomed flask fitted with a reflux (double surface) condenser, warm until the sodium hydroxide dissolves, add the ester layer and reflux the mixture for a period of 15 minutes. Rearrange the fl for distillation (Fig. II, 13, 3) and distil off the methyl alcohol until the residue becomes pasty. Then add about 200 ml. of water and continue the distillation until the temperature reaches 98-100°. Pour the residue in the flask, consisting of an aqueous solution of sodium isovalerate, into a 600 ml. beaker and add sufficient water to dissolve any solid which separates. Add slowly, with stirring, a solution of 15 ml. of concentrated sulphuric acid in 50 ml. of water, and extract the liberated acid with 25 ml. of carbon tetrachloride. Combine this extract with extract (A), dry with a little anhydrous magnesium or calcium sulphate, and distil off the carbon tetrachloride (Fig. II, id, 4 150 ml. distilling or Qaisen flask), and then distil the residue. Collect the isovaleric acid 172-176°. The yield is 56 g. 

A somewhat different scheme is used to gain entry to the alternate symmetrical 1,3,4-thiadiazole ring system. Reaction of thiosemicarbazide with isovaleric acid affords the ring system (217) in one step. The reaction may be rationalized by positing acylation to intermediate 216 as the first step. Sulfonylation of the amino group of 217 with p-methoxybenzenesulfonyl chloride affords the oral... 

Isopropyl-4-m ethyl-1,4-cyclohexadiene, tl 1 Isovaleric acid, ml84 4-Ketovaleric acid, o63... 

Metabolism of the 2,S -isomers proceeds sequentially hydroxylation at the phenoxy group, hydrolysis of the cyano group, and cleavage of the ester linkage (Coats et al. 1989). Fenvalerate and the IS-isomers yield two ester metabolites in feces from hydroxylation at the 4 - and 2 -phenoxy positions. Other significant metabolites were 3-phenoxybenzoic acid and its hydroxy derivatives from the alcohol moiety, 3-(4-chlorophenyl) isovaleric acid and its hydroxy derivatives from the acid moiety, and thiocyanate and carbon dioxide from the cyano moiety (Ohkawa et al. 1979). A slow elimination rate characterizes fenvalerate and other a-cyano pyrethroids when compared with... 

Phoracantha species contained 6-methylsalicylic aldehyde 191, the dis-ubstituted cyclopentene phoracanthal 192, the corresponding alcohol, phora-canthol, and the (E)- and (Z)-stereoisomers of the saturated system. In addition, methyl and ethyl esters of 2-methylbutyric acid and isovaleric acid as well as the macrocyclic lactones decan-9-olide (=phoracantholide I), (Z)-dec-4-en-9-olide (=phoracantholide J) 193, and 11 -hydroxytetradec-5-en-13-olide 194 [8,355, 356]. As shown by independent syntheses of both enantiomers, the natural phoracantholides show ( -configuration [357]. 

Type iii-b This reaction leads to products (67). The electrochemical oxidation of the sodium salts of acetic, propionic, and isovaleric acids in the presence of ethylenic compounds bearing electron-withdrawing substituents gives 1,2-dialkylated adducts as the main products. A methyl radical generated from an acetate ion reacts with diethyl fumarate to give diethyl 2,3-dimethylsuccinate in 80% yield [106]. 

Primary alcohols are readily oxidized to acids by Ni(III) hydroxide as the electron carrier. An example is the electrooxidation of isoamyl alcohol (92) in H2O-NaOH/Ni(OH)3-(Pt) to give isovaleric acid (93) in a good yield (Scheme 34) [127]. 

The sesquiterpenes present in valerian include isovaleric acid, valerenic acid, valerenal, valeranone, and valerenol. The alkaloids found in valerian include valeranine and actinidine. 

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