Production isovaleraldehyde

Prior to 1975, reaction of mixed butenes with syn gas required high temperatures (160—180°C) and high pressures 20—40 MPa (3000—6000 psi), in the presence of a cobalt catalyst system, to produce / -valeraldehyde and 2-methylbutyraldehyde. Even after commercialization of the low pressure 0x0 process in 1975, a practical process was not available for amyl alcohols because of low hydroformylation rates of internal bonds of isomeric butenes (91,94). More recent developments in catalysts have made low pressure 0x0 process technology commercially viable for production of low cost / -valeraldehyde, 2-methylbutyraldehyde, and isovaleraldehyde, and the corresponding alcohols in pure form. The producers are Union Carbide Chemicals and Plastic Company Inc., BASF, Hoechst AG, and BP Chemicals. 

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. 

Raffinate-II typically consists of40 % 1-butene, 40 % 2-butene and 20 % butane isomers. [RhH(CO)(TPPTS)3] does not catalyze the hydroformylation of internal olefins, neither their isomerization to terminal alkenes. It follows, that in addition to the 20 % butane in the feed, the 2-butene content will not react either. Following separation of the aqueous catalyts phase and the organic phase of aldehydes, the latter is freed from dissolved 2-butene and butane with a counter flow of synthesis gas. The crude aldehyde mixture is fractionated to yield n-valeraldehyde (95 %) and isovaleraldehyde (5 %) which are then oxidized to valeric add. Esters of n-valeric acid are used as lubricants. Unreacted butenes (mostly 2-butene) are hydroformylated and hydrogenated in a high pressure cobalt-catalyzed process to a mixture of isomeric amyl alcohols, while the remaining unreactive components (mostly butane) are used for power generation. Production of valeraldehydes was 12.000 t in 1995 [8] and was expected to increase later. 

The first natural product synthesis that utilized the Stetter reaction was reported by Stetter and Kuhhnann in 1975 as an approach to aT-jasmone and dihydrojas-mone (Scheme 21) [93]. Thiazolium pre-catalyst 74 was effective in catalyti-cally generating the acyl anion equivalent with aldehydes 144 and 145, then adding to 3-buten-2-one 146 in good yield. Cyclization followed by dehydration gives cii-jasmone and dihydrojasmone in 62 and 69% yield, respectively, over two steps. Similarly, Galopin coupled 3-buten-2-one and isovaleraldehyde in the synthesis of ( )-rran5-sabinene hydrate [94]. 

The isoprenylation of isovaleraldehyde led to the product in 68% isolated yield, higher than with a conventional procedure using zinc dust in DMF, or refluxing THF. The same procedure was used for the coupling reaction of allylic bromides with aldehydes and ketones, via the preliminary formation of organozinc compounds coming from the reaction between the electrolytic zinc and allylic bromides12. 

Saturated aldehyde (isovaleraldehyde), unsaturated and saturated alcohols (prenol and isoamylic alcohol) simultaneously appear at the initial stage of the reaction prenol is the majoritary product of the reaction but it rapidly undergoes a second hydrogenation. 

Some reviews (41, 52-54) are available. The positive aspects are found in the production of desirable flavors and aromas. Fujimaki and Kurata ( 55) listed aldehydes and pyrazines, volatile compounds produced by heating amino acids with carbonyl compounds, isovaleraldehyde produced by reaction of leucine with carbonyl compounds (aldehydes,... 

Rubika" has a higher concentration of the amino acid leucine therefore in this case more isovaleraldehyde may be generated compared to other volatile products contributing to off-flavor. 

Compound 50c was obtained in ca. 25% yield as a precipitate from the acid-catalyzed condensation of pyrogallol and isovaleraldehyde. No evidence of any hexamer was found in the solid material. To convert this material into the hexamer (50c)6, the original precipitate can be dissolved in Et20, acetone, or methanol, with a few drops of nitrobenzene or o-dinitrobenzene, followed by crystallization upon slow evaporation. The hexamer may also be obtained by thermal treatment of the initial precipitate or the initial filtrate. The product in the initial filtrate may be converted into hexamer by extraction in Et20, followed by evaporation to dryness with subsequent dissolution in methanol. The methanol solution is then heated to 120-150 °C for at least 12 h. Methanol may be removed under vacuum to yield a red-brown solid. Colorless hexameric spherical capsules are obtained from this solid utilizing the crystallization procedure described for the initial precipitate. 

Roasting cocoa beans results in the production of volatile and non-volatile compounds which contribute to the total flavor complex. 5-Methyl-2-phenyl-2-hexenal, which exhibited a deep bitter persistant cocoa note, was reported in the volatile fraction (53). It was postulated to be the result of aldol condensation of phenylacetaldehyde and isovaleraldehyde with the subsequent loss of water. The two aldehydes were the principal products of Strecker degradation products of phenylalanine and leucine, respectively. Non-volatiles contained diketopiperazines (dipeptide anhydride) which interact with theobromine and develop the typical bitterness of cocoa (54). Theobromine has a relatively stable metallic bitterness, but cocoa bitterness is rapidly noticed and disappears quickly. 

The first example of 1,2-asymmetric induction was reported by Yamamoto and coworkers withAf-propylaldimines derived from a-phenylpropionaldehyde (equation 13). The reaction gave mainly the anti product, consistent with a FeUdn-Ahn addition. A 1,3-asymmetric induction took place with the imine prepared from 1-phenylethylamine and isovaleraldehyde, giving a somewhat lower 7 1 diastereoselectivity. 

Various aldehydes are encountered in wine. The most abundant is acetaldehyde which is both a product of yeast metabolism and an oxidation product of ethanol. Glyoxylic acid, resulting from oxidation of tartaric acid, especially catalyzed by metal ions (Fe, Cu) or ascorbic acid, can also be present. Other aldehydes reported to participate in these reactions include furfural and 5-hydroxymethylfurfural that are degradation products of sugar and can be extracted from barrels (Es-Safi et al. 2000), vanillin which also results from oak toasting, isovaleraldehyde, benzaldehyde, pro-pionaldehyde, isobutyraldehyde, formaldehyde and 2-methylbutyraldehyde which are present in the spirits used to produce fortified wines (Pissara et al. 2003). 

Controlled oxidation of a primary alcohol with a mixture of sulfuric and chromic acids gives the corresponding aldehyde. In the preparation of low-molecular-weight aldehydes, an aqueous medium is used and the product is removed by steam distillation, thus preventing further oxidation. This procedure is well illustrated by the preparation of propion-aldehyde (49%) and isovaleraldehyde (60%). Certain benzyl alcohols are dissolved in aqueous acetic acid for chromic acid oxidation. Ole-finic aldehydes are produced by a rapid low-temperature (5-20°) oxidative procedure, as illustrated by the preparation of 2-heptenal (75%) from 2-heptenol. Aldehyde ethers such as methoxyacetaldehyde and ethoxy-acetaldehyde have been prepared by the chromic acid oxidation of the corresponding alcohols in 17% and 10% yields, respectively. ... 

Excellent enantioselectivities for all of these dendrimers were observed in the Michael addition reactions of isovaleraldehyde with nitrostyrene. For example, in the presence of 10mol% of the first-generation catalyst, the addition product 2-isopropyl-4-nitro-3-phenyl-butyraldehyde was isolated in 86% yield with 99% ee and moderate diastereoselectivity (diastereomeric ratio (dr) 80 20). Higher diaste-reoselectivities were observed when the meta-substituted dendrimer catalysts were used, but the yields and enantioselectivities were relatively low. In addition, the second-generation dendrimer catalyst could be easily recovered via precipitahon with methanol and reused at least five times, with only a slight loss of catalytic activity. 

A further aldol condensation employing 56 has been reported [13, 28], The chiral linker 56 was N-acetylated with hydrocinnamoyl chloride and finally treated with isovaleraldehyde. The afforded [3-hydroxylated immobilized product was detached... 

An example of aldehyde formation is the production of isovaleraldehyde by Gluconobacter oxydans R (Fig. 16.2-45) 202, 206. Glycerol-grown Gluconobacter oxydans slowly oxidizes 3-methyl-l-butanol to isovaleraldehyde, with yields of over 90%. The product was recovered by bisulphite trapping or cold traps 202. Extractive bioconversion in a hollow-fiber membrane bioreactor allowed continuous produc-... 

The methylotropic yeast Candida boidinii SA051 showed excellent ability for oxidation of alcohols to aldehydes or ketones. In the production of isovaleraldehyde, the generated aldehyde was up to 50 grams/L. Also this oxidation showed reaction selectivities. It was an example of chemoselectivity that the yeasts preferred (E)-2-hexenol among various C6 alcohols and oxidized it selectively to the desired (E)-2-... 

The root bark yielded l-isobutyl-l,2,3,4-tetrahydro-j3-carboline (B.HCl, mp 257-259°). A synthetic specimen prepared by the condensation of tryptamine with isovaleraldehyde was identical with the natural product (89). 

Hollow-fiber MBR have also been used for the production of a number of other fine chemicals. Molinari et al [4.42] used such a MBR for the production of isovaleraldehyde from isoamyl alcohol using Gluconobacter oxidans. In their work hydrophobic hollow-fiber membranes were used in order to continuously extract the aldehyde, thus, avoiding its oxidation to the corresponding acid. Hollow-fiber MBR have also been used by Ko-yama et al [4.27] in the synthesis of L-aspartic acid by E. coli, and by Cantarella et al... 

Polymeric Evans auxiliary 76 was also applied to aldol reactions2 4 (Scheme 1.6.37). In a model reaction, immobilised dihydrocinnamic acid was converted into the boron enolate and reacted with isovaleraldehyde. Products were released by treatment of the resin with NaOMe. The p-hydroxy ester 79 was obtained in a 20 1 diasteromeric ratio, along with some ester 80 derived from unreacted starting material. 

---