Alcohol , microbial oxidation

Gestodene has been prepared in several ways (85). The route that provides the highest yield is shown in Eigure 8. Microbial oxidation of (55) with Penicillium raistrickii results in the 15-alcohol (56). Protection of the alcohol as the acetate (57) and protection of the ketone as a dienolether provides (58). In a one-pot procedure (58) is treated with lithium acetyUde and subjected to a hydrolytic work-up to provide gestodene (54) (86). 

Oxidation of secondary or primary alcohols by dehydrogenases is usually not performed biocatalytically. The reaction destroys a stereocentre, it is thermodynamically not favoured and product inhibition is a problem. It is attractive only in cases where it is necessary to discern between several hydroxy groups in a molecule. Microbial oxidation of D-glucitol to yield L-sorbose is the key step in production of vitamin C (Reichstein and Griissner, 1934). 

Subterminal alkane oxidation apparently occurs in some bacterial species (Markovetz, 1971). This type of oxidation is probably responsible for the formation of long-chain secondary alcohols and ketones. Pirnik (1977) and Perry (1984) have reviewed the microbial oxidation of branched and cyclic alkanes, respectively. Interestingly, none of the cyclohexane or cyclopentane compounds seems to be metabolized by pure cultures. Rather, non-specific oxidases present in many bacteria convert the cyclic alkanes into cyclic ketones, which are then oxidized by specific bacteria. 

The role of PQQ as cofactor has been established unequivocally only for a number of dehydrogenases that are located in the periplasmic space of gram-negative bacteria [3] (Table 1). These enzymes are involved in the oxidation of alcohols and sugars (to aldehydes and sugar lactones or ketosugars, respectively), especially in processes known as incomplete microbial oxidations [47] (production... 

The food additive carnitine (25) is worthy of mention because it has a very close structural relationship to some beta blockers. It is also called vitamin BT. There are many potential routes to this compound, including an asymmetric hydrogenation method.234 236 The method is closely related to that used for Lipitor (Section 31.2.1). Reduction of 4-chloro-3-oxobutyrate provides the desired alcohol isomer. Ester hydrolysis and reaction with triethylamine affords 25. There are two other major approaches one relies on an asymmetric microbial oxidation (Scheme 31.22).237... 

Microbial oxidation of alkanes can take place at the terminal carbon, in which case an alcohol is the initial product, or at a subterminal position (often the -position) to give either the secondary alcohol or a ketone. In both cases further oxidation s can take place to give carboxylic acids, themselves liable to oxidation and shortening of the carbon chain by successive two-carbon units (Scheme 2). 

Acyclic tritetpenes can be considered as aliphatic hydrocarbons and are a iydroxylated by a numbo of microorganisms. The microbial oxidation of a varied of acyclic terpenoid hydrocarbons has been investigated by Nakajima, and aldrough terminal alcohols can obtained, for example pristanol (39) from pristane (38 equation 11), further oxidation can also occur. 

Anthony, C., and Zatman, L. J., 1967, The microbial oxidation of methanol The prosthetic group of alcohol dehydrogenase of Pseudomonas sp. M27 A new oxidoreductase prosthetic group. Biochem. J. 104 9609969. 

Microbial Oxidation of Alcohols by Candida boidinii Selective Oxidation... 

Oxidation of Meso Diols. Asymmetric induction of meso and prochiral diols by lipases is very successful in the field of organic synthesis. Also it is well known that selective oxidation of prochiral or meso diols by HLADH provides oxidized products with a significant degree of enantioselectivity. However, it has not been reported that alcohol oxidases were applied to such types of oxidation. The microbial oxidation of meso diols by Candida boidinii SA051 was carried out and gave optically active hydroxy ketones (Figure 8). 

NOZAKIET AL. Microbial Oxidation of Alcohols fry Candida boidinii 195... 

The synthesis of kifunensine (1) was also achieved from the 5-deoxy-5-azidomannolactone derivative 8, obtained from cw-cyclohexadienediols by microbial oxidation using Pseudomonas putida 39D, ° by isopropylidenation followed by reduction to furnish 9 in 30% yield. Treatment of 9 with dimethyl oxalate followed by methano-lic ammonia furnished intermediate 10 (55%), which underwent oxidation of the primary alcohol to the aldehyde followed by cycUzation in methanolic ammonia to afford 11. Removal of the diacetoiude groups from 11 with 75% trifluoroacetic acid gave (+)-l. 

In Banwell s de novo synthesis of Neu5Ac [136] cis-1,2-dihydrocatechol 228, a product of microbial oxidation of chlorobenzene, has been converted into a protected form of Neu5Ac via a fifteen steps reaction sequence (Scheme 50). Synthesis started from azido alcohol 229, obtained from catechol 228 by an established procedure [137]. This was subjected to ozonolytic cleavage and a reductive work-up to afford diol 230. Protection-deprotection reaction sequence led to alcohol 232 which was then oxidized to D-mannosamine derivative 233 using the Swem protocol. Condensation with the organozinc reagent derived from... 

Novel mixtures of optical isomers of natural and kosher styrallyl alcohol (a-phenylethyl alcohol), and their corresponding acetate esters of styrallyl alcohol (a-phenylethyl acetate) were prepared by multiple fermentation processes and an azeotropic esterification reaction. In the first step, natural acetophenone was produced by bioconversion of cinnamic acid by Pseudomonas sp. (P), Comanonas sp, and Arthrobacter sp. 6). In the first microbial oxidation process, the side chain of cinnamic acid was oxidized to the ketone to form acetophenone that was transiently accumulated in the fermentation broth (P). The current commercial fermentation process yielded >5g/L of acetophenone in the fermentation broth following 2 days of incubation using Arthrobacter sp. The resulting acetophenone was recovered and purified from the fermentation broth by solvent extraction followed by fractional distillation. Acetophenone itself can be used in creating flavor formulations and in enhancement of aroma and taste or both. 

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