A convenient method for the preparation of β-hydroxy esters

Kuwajima, Isao; Minami, Naoki; Sato, Toshio

doi:10.1016/0040-4039(76)80042-1

Cited by 11 publications

(2 citation statements)

References 4 publications

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“…Purity was determined by NMR and GC, and all compounds were confirmed to be >98% pure. [6]-Gingerol (6G) ( 1 ) was prepared as a racemic mixture according to a previously described method (Scheme a). Synthesis of aza-[6]-gingerol (A6G) ( 2 ) was conducted by starting with ethyl 3-( tert -butyldimethylsilyloxy)octanoate 3 as shown in Scheme b.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of a New [6]-Gingerol Analogue and Its Protective Effect with Respect to the Development of Metabolic Syndrome in Mice Fed a High-Fat Diet

et al. 2011

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To determine the effects of a [6]-gingerol analogue (6G), a major chemical component of the ginger rhizome, and its stable analogue after digestion in simulated gastric fluid, aza-[6]-gingerol (A6G), on diet-induced body fat accumulation, we synthesized 6G and A6G. Mice were fed either a control regular rodent chow, a high-fat diet (HFD), or a HFD supplemented with 6G and A6G. Magnetic resonance imaging adiposity parameters of the 6G- and A6G-treated mice were compared with those of control mice. Supplementation with 6G and A6G significantly reduced body weight gain, fat accumulation, and circulating levels of insulin and leptin. The mRNA levels of sterol regulatory element-binding protein 1c (SREBP-1c) and acetyl-CoA carboxylase 1 in the liver were significantly lower in mice fed A6G than in HFD control mice. Our findings indicate that A6G, rather than 6G, enhances energy metabolism and reduces the extent of lipogenesis by downregulating SREBP-1c and its related molecules, which leads to the suppression of body fat accumulation.

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Section: Methodsmentioning

confidence: 99%

Synthesis of a New [6]-Gingerol Analogue and Its Protective Effect with Respect to the Development of Metabolic Syndrome in Mice Fed a High-Fat Diet

et al. 2011

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“…The organic phases were combined and evaporated under reduced pressure to give a residue (0.065 g) which was dissolved in CHCI,-MeOH 7 : 3 and filtered through silica gel to give, after evaporation of the solvent, pure (22R)-3a,7a,22-trihydroxycho!an-24-oic acid (14d) (0.06 g, 76%), m.p. 133-136 "C (lit.," 141-142 "C); G(CD,OD), 0.72 (3 H, s, 18-Me), 0.92 (3 H, s, 19 (22S)-3a,7a,22-Trihydroxy-5P-cholan-24-oic Acid (Haemulcholic Acid) (14c).-The (22s)-hydroxy ester (14a) (0.78 g, 1.5 mmol) and 10% KOH-MeOH was stirred and treated under reflux for 7 h. The mixture was then poured into water (50 ml), acidified with concentrated hydrochloric acid, extracted with ethyl acetate-methanol 95:5 (4 x 30 ml) and the combined organic layers were evaporated and dried under reduced pressure. Flash filtration of the residue through silica gel and elution with CHC1,-MeOH 7 : 3 gave pure haemulcholic acid Ethyl 3a,7a-Diacetoxy-22-oxo-5~-cholun-24-oute (13).-A mixture of the a-diazo-P-hydroxy ester (12) (1.0 g, 1.83 mmol) and dirhodium(I1) tetra-acetate (0.005 g, 0.011 mmol) in 1,2dimethoxyethane (DME) (10 ml) was stirred at room temperature for 15 min and the solvent was then evaporated off.…”

Section: Ethyl 3a7a-diacetoxy-22-hydroxy-23-diazo-5~-cholan-24oatementioning

confidence: 99%

Reduction of α-diazo-β-hydroxy esters to β-hydroxy esters: application in one of two convergent syntheses of a (22S)-22-hydroxy bile acid from fish bile and its (22R)-epimer

Pellicciari¹,

Natalini²,

Cecchetti³

et al. 1985

J. Chem. Soc., Perkin Trans. 1

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a-Diazo-P-hydroxy esters (3) prepared by condensation of aldehydes (1 ) with ethyl (1ithio)diazoacetate(2) are reduced with 5% palladium over charcoal in methanol into the corresponding f3hydroxy esters (5) in high yield. This sequence is applied to a new synthesis of haemulcholic acid ( I ~c ) , a ( 2 2 9 -2 2hydroxy bile acid from fish bile and its (22R)-epimer (1 46). A convergent synthesis of (1 4c) and (14d) involves, as a key step, the dirhodium(ii) tetra-acetate conversion of (1 2) into the corresponding f3-keto ester (1 3).Previous work has established the synthetic versatility of adiazo-9-hydroxyacylmethanes, trifunctionalized compounds readily accessible by an aldol-type condensation between alithiated diazoacyl precursors, and aldehydes and ketones. ''-'In particular, the dirhodium(I1) tetra-acetate catalyzed conversion of a-diazo-b-hydroxy esters (3), prepared by reaction of ethyl (1ithio)diazoacetate (2) with aldehydes (1) followed by neutralization with acetic acid, affords the corresponding pketo esters (4)1".p in nearly quantitative yields (Scheme 1).

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