3-Hydroxy butanoate

Fig. 13. Chiral dendrimers of 2nd generation from trimesic and (i )-3-hydroxy-butanoic acid [56,57]...

The residue was distilled with a Kugelrohr apparatus under water aspirator vacuum (approximately 20mbar, 140 °C) to give (,SY)-methyl-(3)-hydroxy-butanoate (105 mg, 99%). 

Chiral 4-chloro-3-hydroxybutanoate esters are important chiral C4-building blocks [43-53]. For example, (i )- and (S)-isomers can be converted to L-car-nitine and the hydroxymethyl glutaryl-CoA reductase inhibitor. Since these compounds are used as pharmaceuticals, a high optical purity is required. A practical enzymatic method for the production of chiral 4-chloro-3-hydroxy-butanoate esters from prochiral carbonyl compounds, i.e.,4-chloroacetoacetate esters, or racemic 4-chloro-3-hydroxybutanoate esters is described. 

The reduction of 4-chloroacetoacetate ethyl ester (CAAE) to 4-chloro-3-hydroxy-butanoate ethyl ester (CHBE) usually proceeds stereospecifically [54, 55]. This activity is widely distributed in yeasts, molds and bacteria, most of which give the (S)-enantiomer. Sporobolomyces salmonicolor was found to produce the (l )-enan-tiomer predominantly (62% e. e.) with high molar conversion [54,55], and several Candida yeasts formed (S)-CHBE of high optical purity (> 90% e. e.) [54,55]. 

Moreover, lipase-catalyzed reactions of linear and cyclic poly(3-hydroxy-butanoates) were subjected to hydrolysis, transesterification, and intramolecular esterification. A cyclic polymer along with linear polymers was pro-... 

Recently, we [67] have described the reduction of the methyl ester of 4-chloro-3-oxobutanoic acid (39) to the methyl ester of S-( )-4-chloro-3-hydroxy-butanoic acid (40) (Fig. 13) by cell suspensions of Geotrichum candidum SC 5469., S ( )-(40) is a key chiral intermediate in the total chemical synthesis of a cholesterol antagonist (SQ 33600), which acts by inhibiting hydroxymethylglu-taryl CoA (HMG CoA) reductase. In the biotransformation process, a reaction... 

Amination,1 The reaction of the dioxanone 2, derived from (R)-3-hydroxy-butanoic acid, with di-r-butyl azodicarboxylate (14,115-116) provides the derivative 3 in high diastereomeric excess. The same amination of an alkyl (R)-3-hydroxy-... 

Figure 4. Preparation of the enantiomers of ethyl 3-hydroxy butanoate. Reagents a) Saccharomyces bailii KI 0116 (80%) ...

When the enantioselective reduction of ethyl 4-chloroacetoacetate was carried out with alcohol dehydrogenase from Candida parapsilosis, the other enantiomer was produced ethyl (P)-4-chloro-3-hydroxybutanoate [134]. This product is a key intermediate in a synthesis of (R)-carnitine. In this case a substrate coupled approach was chosen. The enzyme also has a strong oxidation activity for 2-propanol, which was therefore selected as the cosubstrate. The situation is depicted in Fig. 3.50. Under optimized conditions, the yield of (R)-ethyl-4-chloro-3-hydroxy-butanoate reached 36.6 g L-1 (> 99% ee, 95% yield) on a 30 L scale. 

A bulkier 2-substituent leads to a reversal of the selectivity for baker s yeast reduction of (3-keto esters and gives a higher proportion of the cwti-diastcreomer (Table 5)1,7 121. For example, ethyl 2-benzy]-3-oxobutanoate leads to a 22% yield of ethyl 2-benzyl-3-hydroxybutanoate with a synjanti ratio of 35 65 while a 2-allyl substituent gives 84% yield of ethyl 2-allyl-3-hydroxy-butanoate with a synjanti ratio of 25 75. 

The four stereoisomers of 2-amino-3-hydroxy butanoic add (threonine). 

Karanewsky DS, Badia MC, Ciosek CP, et al. Phosphorns-containing inhibitors of HMG-CoA reductase. I. 4-[(2-Arylethyl)hydroxyphosphinyl]-3-hydroxy-butanoic acids a new class of cell-selective inhibitors of cholesterol biosynthesis. Journal of Medicinal Chemistry 33 11), 2952, 1990. 

The polymer polyhydroxybutyrate (PHB), a polyester of 3-hydroxy-butanoic acid, is completely biodegradable as it is an ideal food for microbes. By copolymerization with another hydroxyacid, such as 3-hydroxypentanoic acid, the polymer can be tailored to take it suitable either for molded articles such as shampoo bottles or thin films for plastic envelopes or carrier bags. PHB is tradenamed Biopol by ICI. Most of the polymer that the company makes is used for packaging, agricultural products, and items of personal hygiene. Wella, the German hair-care company, sells its Sanara brand of shampoo in bottles made of Biopol and has reported increased sales as a result. 

In an independent study of the Claisen rearrangement of the E- and Z-crotyl esters of the 3-hydroxy butanoate, Kurth and Yu [39] isolated a mixture of two diastereomers each. NMR analysis of the 1,3-dioxanes, derived from the rearrangement products, was used to assign the stereochemistry at the 3,4 positions on the basis of coupling constants in the NMR spectra. To establish the stereochemistry at the 4,5 positions, ( )-botryodiplodin, a mycotoxin with both antibiotic and antileukemic properties, and its isomer 3-epibotryodiplodin were synthesized from the rearrangement products (Scheme 5.1.27) [39]. 

Poly(3-hydroxybutanoic acid), a biodegradable polyester, is an insoluble, opaque material that is difficult to process into shapes. In contrast, the copolymer of 3-hydroxy-butanoic acid and 3-hydroxyoctanoic acid is a transparent polymer that shows good solubility in a number of organic solvents. Explain the difference in properties between these two polymers in terms of their structure. 

He, J., Sim, Z Ruan, W., and Xu, Y. (2006) Biocatalytic synthesis of ethyl (S)-4-chloro-3-hydroxy-butanoate in an aqueous-organic solvent biphasic system using Aureobasidium pullulans CGMCC 1244. Process Biochem., 41 (1), 244-249. 

The poly(HASCL) containing units other than 3HB and 3HV include different tercopolymers, such as poly(3HB-co-3HV-co-5HV) (R. eutropha) [90] and poly(3HB-co4HB) R. eutropha) [91]. Poly(3HB-co-3HV-co-5HV) and poly-(3HB-CO-4HB) are less crystalline and more biodegradable than poly(3HB-co-4HB). 3-Hydroxy-2,2-dimethyl-propanoic acid was polycondensed (Rhodocodus ruber) [92], as well as 3-pentenoic acid (Burkolderia) [93] and 4-pentanoic acid (Rhodospirilhum) [94] these acids were also copolycondensed with 3-hydroxy-butanoate, 3-hydroxy-pentanoate, and 3-hydroxy-2,2-dimethyl-propanoic acid. 

Poly(3-hydroxybutyric acid- Bipol PHBV 3-hydroxy butanoic 80181-31-3 homopol ner PenUmoic acid, 3-hy oxy-, R (C5HI0O3 -... 

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