3- Hydroxybutyrate methyl ester

A degradation product of microbially synthesized polyhydroxybu-tyrate (PHB), 3-hydroxybutyrate (3HB), can be an alternative to glucose during sustained hypoglycemia. The 3HB derivative 3-hydroxybutyrate methyl ester (HBME) is used by cells as an alternative to glucose. HBME inhibited cell apoptosis under glucose deprivation, rescued activities of mitochondrial respiratory... 

Zhang J, Cao Q, Li S, Lu X, Zhao Y, Guan JS et al (2013) 3-Hydroxybutyrate methyl ester as a potential drug against Alzheimer s disease via mitochondria protection mechanism. Biomaterials 34 7552-7562... 

Recently, Zhang et al (2009) showed that 3-hydroxybutyrate methyl ester (3HBME) and mcl 3-hydroxyaIkanoate methyl ester (3HAME) obtained from esterification of PHB and mcl PHA could be used as biofuels (Fig. 6). They investigated the combustion heats of 3HBME, 3HAME, ethanol, n-propanol, n-butanol, 0 diesel. 

Zou XH, Li HM, Wang S, Leski M, Yao YC, Yang XD, Huang QJ, Chen GQ (2009) The effect of 3-hydroxybutyrate methyl ester on learning and memory in mice. Biomaterials 30 1532-1541... 

Figure 16.8 Polyhydroxyalkanoates (PHA) can be produced from activated sludge generated from wastewater treatments. PHA-based biofuels including 3-hydroxybutyrate methyl ester (3HBME) and 3-hydroxyalkanoate methyl esters (3HAME) can also be formed from methyl-esterifying PHA. ...

Wang SY, Liu MM, Xu Y, Zhang 7, Chen GQ. Properties of a new gasoline oxygenate blend component 3-hydroxybutyrate methyl ester produced from bacterial poly-3-hydroxybutyrate. Biomass Bioenerg 2010 34 1216-22. 

Dinjus E, Arnold U, Dahmen N, Hofer R, Wach W. Green fuels — sustainable solutions for transportation. In Hofer R, editor. Sustainable solutions for modern economies. Cambridge RSC Publ 2009. p. 125-63. Wang SY, Liu MM, XuY, Zhang XJ, Chen GQ. Properties of a new gasoline oxygenate blend component 3-hydroxybutyrate methyl ester produced from bacterial poly-3-hydroxybutyrate. Biomass Bioenerg 2010 34 1216-22. 

Amide 26a can be converted directly to methyl ester 27 upon treatment with 3% methanol— HCl. This ester is used as a starting point for the synthesis of 7-amino-jS-hydroxybutyric acid (32), a GABA derivative of great biological and synthetic importance (Scheme 3) [30]. 

Mild hydrolysis of butirosin A and B with acid slowly liberated n-xylose and n-ribose, respectively. Hydrolysis with concentrated acid gave neamine, neosamine C, 2-deoxystreptamine, and a novel amino acid, 4-amino-3,4-dideoxy-L-gtycero-tetronic acid [(S)-( —)-4-amino-2-hydroxybutyric acid] (53). Treatment of the methyl ester of this amino... 

Liu JH, Jen HL, Chung YC (1999) Surface modification of polyethylene membrans using phos-phorylcholine derivatives and their platelet compatibility. J Appl Polym Sci 74 2947-2954 Loh SK, ChooYM, Cheng SF, Ma A (2006) Recovery and conversion of palm olein-derived used frying oil to methyl esters for biodiesel. J Oil Palm Res 18 247-252 Loo C-Y, Lee W-H, Tsuge T, Doi Y, Sudesh K (2005) Biosynthesis and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from pahn oQ products in a Wautersia eutropha mutant. Biotechnol Lett 27 1405-1410... 

Hydroxybutyric acid, methyl ester, A1.22 Lactic acid, ethyl ester, A1.9 Cyclopentane-1,2,3-triol, A"22.10... 

Seebach, D., Beck, A.K., Breitschuh, R., Job, K., 2003. Direct degradation of the biopolymer poly[(R)-3-hydroxybutyric acid] to (R)-3-Hydroxybutanoic acid and its methyl ester. In Organic Syntheses, 71. John Wiley Sons, Inc, pp. 39—47. 

The hydrolysis-gas chromatography technique applied to copolymer analysis has already been described in the literature and is accurate to within about 2%. However, it contains a systematic error in that it is difficult to ensure complete conversion of the monomer units to their respective methyl esters and some dehydration to the corresponding or,)3-unsaturated ester (e.g. hydroxybutyrate to crotonate) usually occurs. The liquid chromatography technique suffers from similar problems but the hydrolysis to free acid using perchloric acid tends to be a cleaner reaction than methanolysis and it is our experience that comonomer ratios can be determined with an accuracy better than 1%. 

Chiral monomers of PHA can also be used for the synthesis of drugs or others used for fine chemicals [5, 6]. For example, one of the most common PHA monomers, 3-hydroxybutyrate (3HB), is a potential memory-enhancing drug when turned into 3HB methyl ester [32] (Fig. 6). Several amphiphilic proteins, namely PhaP or phasin attached to hydrophobic PHA granules, were used to aehieve protein purification or specific drug delivery (targeting) [26,28] (Fig. 7). It appears that PHA has many potential applications waiting to be exploited. 

Hydroxybutyric acid 3-Hydroxy-2-methylpropionic acid 2-Methoxypropionic acid Lactic acid, methyl ester... 

Hydroxy-3-methylbutyric acid 2-Hydroxybutyric acid, methyl ester Lactic acid, ethyl ester A24.il A 1.22 A 1.9 2-Methylbutane-1,2-diol 2-Methylbutane-1,4-diol 2-Methylbutane-2,3-diol C5H12O3 A33.7 A27.20 A12.9... 

Fig. 5.14 Mass spectra of the methyl esters of (a) benzoic acid, (b) 4-hydroxyphenylacetic acid and (c) mandelic acid and (d) of the methyl ester-trimethylsilyl ether of 3-hydroxybutyric acid.

Fig. 7.6 Chromatogram of organic acids extracted from deproteinized whole blood using diethyl ether, and separated as their methyl esters (diazomethane) and oxo acid methoximes on a glass column packed with 3 per cent Carbowax 20M plus 5 per cent silicone fluid XF-1150 on Chromosorb W (AWTMCS, 100-120 mesh) using temperature programming from 75°C to 180°C at 4°C min" Peak identifications are 1, lactate 2, pyruvate 3, acetoacetate (peak 1) plus oxalate 4, acetoacetate (peak 2) 5, 3-hydroxybutyrate 6, ethylmalonate (internal standard). (Redrawn with modifications from Hagenfeldt, 1968)...

Diagnosis may be made using gas chromatography alone (Gompertz et al, 1974), and this may be illustrated by reference to methylmalonic aciduria. Fig. 9.3 shows the chromatogram of amniotic fluid containing 9 tg of methyl-malonate ml as its methyl ester, obtained by ether extraction. Because of the possible confusion of methylmalonate with 3-hydroxybutyrate, a normal amniotic fluid constituent (Section 8.1), or 2-methyl-3-hydroxybutyrate, depending on the GC column used, these authors advised the use of mass... 

Ketone body synthesis occurs only in the mitochondrial matrix. The reactions responsible for the formation of ketone bodies are shown in Figure 24.28. The first reaction—the condensation of two molecules of acetyl-CoA to form acetoacetyl-CoA—is catalyzed by thiolase, which is also known as acetoacetyl-CoA thiolase or acetyl-CoA acetyltransferase. This is the same enzyme that carries out the thiolase reaction in /3-oxidation, but here it runs in reverse. The second reaction adds another molecule of acetyl-CoA to give (i-hydroxy-(i-methyl-glutaryl-CoA, commonly abbreviated HMG-CoA. These two mitochondrial matrix reactions are analogous to the first two steps in cholesterol biosynthesis, a cytosolic process, as we shall see in Chapter 25. HMG-CoA is converted to acetoacetate and acetyl-CoA by the action of HMG-CoA lyase in a mixed aldol-Claisen ester cleavage reaction. This reaction is mechanistically similar to the reverse of the citrate synthase reaction in the TCA cycle. A membrane-bound enzyme, /3-hydroxybutyrate dehydrogenase, then can reduce acetoacetate to /3-hydroxybutyrate. 

Catalytic asymmetric hydrogenation is a relatively developed process compared to other asymmetric processes practised today. Efforts in this direction have already been made. The first report in this respect is the use of Pd on natural silk for hydrogenating oximes and oxazolones with optical yields of about 36%. Izumi and Sachtler have shown that a Ni catalyst modified with (i ,.R)-tartaric acid can be used for the hydrogenation of methylacetoacetate to methyl-3-hydroxybutyrate. The group of Orito in Japan (1979) and Blaser and co-workers at Ciba-Geigy (1988) have reported the use of a cinchona alkaloid modified Pt/AlaO.i catalyst for the enantioselective hydrogenation of a-keto-esters such as methylpyruvate and ethylpyruvate to optically active (/f)-methylacetate and (7 )-ethylacetate. 

Carboxvalkvlation of Propylene Oxide. These reagents were also used in a similar carboxyalkylation scheme to prepare methyl 3-hydroxybutyrate by reaction with propylene oxide (Equation 3). This might represent a way to prepare substitute 1,3 diols(48) following reduction of the ester or reactive monomers by pyrolys is/dehydration. 

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