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... 

Other appHcations of amyl alcohols include their use as flavor and fragrance chemicals. Amyl isovalerate and amyl saHcylate consumed a maximum of 450 t of amyl alcohols (150). Isoamyl saHcylate is used to a large extent in soap and cosmetic fragrances because of its cost effectiveness (167). Isoamyl... 

Factors affecting the accumulation of ansamitocins P-2, P-3, and P-4 in JSbocardia sp. C-15003 have been studied (246) the addition of isoleucine, propionate, ptopionaldehyde, or -ptopyl alcohol to the fermentation medium resulted in the increased production of P-2 the addition of valine, isobutyrate, isobutyraldehyde, or isobutyl alcohol increased the production of P-3, reaching more than 90% of the total ansamitocins produced and the addition of leucine, isovalerate, isovaleraldehyde, or isoamyl alcohol increased the production of P-4. 

Most commercial sorbic acid is produced by a modification of this route. Catalysts composed of metals (2inc, cadmium, nickel, copper, manganese, and cobalt), metal oxides, or carboxylate salts of bivalent transition metals (2inc isovalerate) produce a condensation adduct with ketene and crotonaldehyde (22—24), which has been identified as (5). 

Uses ndReactions. Camphene is used for preparing a number of fragrance compounds. Condensation with acids such as acetic, propionic, isobutyric, and isovaleric produce usehil isobomyl esters. Isobomyl acetate (41) has the greatest usage as a piae fragrance (81). The isobomyl esters of acryhc and methacrylic acids are also usehil ia preparing acryUc polymers. 

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. 

Chemical Designations - Synonyms Isovaleral Isovaleric aldehyde 3-Methylbutanal 3-Methylbutyraldehyde Chemical Formula (ClyjCHCHjCHO. 

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. 

French oil of peppermint eontains. in addition to menthol and iia, isovaleric aldehyde, isoamyl alcohol, i-pinenc. A -p-monthcne aed... 

---