23513-13-5

Herein we report the first organocatalysed enantioselective synthesis of gingesulfonic acids and shogasulfonic acids via a mild and convenient aminothiourea-catalysed conjugate addition of bisulfite to the olefin moiety of α,β-unsaturated carbonyls - a technology previously reported by us. A series of optically active naturally occurring sulfonic acids are prepared in their natural and unnatural configurations, and their absolute configurations are unequivocally confirmed by single crystal X-ray diffractometry.

The invention discloses a preparation method of (E)-1-(4-hydroxy-3-methoxyphenyl)-4-ene-3-decalone and relates to the field of medicinal chemistry. The method comprises the steps as follows: 1) 4-(4-hydroxy-3-methoxyphenyl)-2-butanone is dissolved in a halogenated hydrocarbon solvent, pyrrolidine or piperidine is added at the room temperature, and the mixture reacts for 15-120 min; 2) a halogenated hydrocarbon solution of n-hexaldehyde is added, and the mixture reacts for 2-24 h; 3) an inorganic base solution is added, the mixture reacts for 1-24 h, aftertreatment is performed, and a compoundshown in formula (1) is prepared. Reactions at the room temperature are conducted with inorganic base and other weak bases, and the total yield is 78% or above. The method has mild reaction conditionsand is convenient to operate and suitable for industrial production.

[6]-Gingerol and [6]-shogaol are the major pungent components in ginger with a variety of biological activities including antioxidant activity. To explore their structure determinants for antioxidant activity, we synthesized eight compounds differentiated by their side chains which are characteristic of the C1-C2 double bond, the C4-C5 double bond or the 5-OH, and the six- or twelve-carbon unbranched alkyl chain. Our results show that their antioxidant activity depends significantly on the side chain structure, the reaction mediums and substrates. Noticeably, existence of the 5-OH decreases their formal hydrogen-transfer and electron-donating abilities, but increases their DNA damage- and lipid peroxidation-protecting abilities. Additionally, despite significantly reducing their DNA strand breakage-inhibiting activity, extension of the chain length from six to twelve carbons enhances their anti-haemolysis activity.

In order to explore the structural determinants for the TRPV1 and TRPA1 agonist properties of gingerols, aseries of nineteen analogues (1b-5) of racemic [6]-gingerol (1a) was synthesized and tested on TRPV1 and TRPA1 channels. The exploration of the structure-activity relationships, by modulating the three pharmacophoric regions of [6]-gingerol, led to the identification of some selective TRPV1 agonists/desensitizers of TRPV1 channels (3a, 3f, and 4) and of some full TRPA1 antagonists (2c, 2d, 3b, and 3d). 2011 Elsevier Ltd. All rights reserved.

Shogaols, the pungent principle of ginger, exhibit interesting bioactivities. Practical preparation of shogaols is highly desired. Here we report the protection/deprotection-, salt-, and metalfree synthesis of shogaol in three steps by use of dimethylammonium dimethyl carbamate (DIMCARB), in which DIMCARB smoothly promoted Mannich-type condensation of the ketone donor with the aldehyde acceptor through the iminium cation intermediate. Georg Thieme Verlag Stuttgart.

In accordance with the invention, an industrial process for producing shogaols useful in the fields of for example foods, flavor, pharmaceutical products, qui-pharmaceutical products and cosmetics can be provided. The invention relates to novel intermediates represented by the following general formula and a process for producing shogaols from the intermediates. In accordance with the invention, shogaols can readily be produced, of which mass production has been difficult because shogaols have been produced only by the extraction process from a natural ginger. Intermediates; (in the formula (1), R1 represents hydrogen atom or methyl group; R2 represents optionally branched alkyl group with one to 18 carbon atoms; R3 and R4 each independently represents hydrogen atom, a lower alkyl group or a protective group of the phenolic hydroxyl group; A represents an alkylene group with one to 4 carbon atoms; and X represents benzenesulfonyl group or toluenesulfonyl group.)

Ten shogaols were synthesized to evaluate the importance of the side-chain length in protecting cells from βA(1-42) insult using PC12 rat pheochromocytoma and IMR-32 human neuroblastoma cells. The compounds cell protectivity against βA insult was demonstrated using 3-[4,5- dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The efficacy of cell protection from βA insult by these shogaols was shown to improve as the length of the side chain increase.

Gingerols, pungent principles of ginger (the rhizome of Zingiber officinale), are biologically active components that may make a significant contribution towards medicinal applications of ginger and some products derived from ginger. Gingerols, however, are thermally labile due to the presence of a β-hydroxy keto group in the structure, and undergo dehydration readily to form the corresponding shogaols. This study investigated the stability of [6]-gingerol [5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)decan-3-one] at temperatures ranging from 37 to 100°C in aqueous solutions, at pH 1, 4, and 7. Quantitative measurements of [6]-gingerol and its major degradation product [6]-shogaol [1-(4-hydroxy-3-methoxyphenyl)decan-4-ene-3-one] were performed by HPLC. Kinetics of [6]-gingerol degradation was characterized by least square fitting of a rate equation. It was found that gingerol exhibited novel reversible kinetics, in which it undergoes dehydration-hydration transformations with shogaol, the major degradation product. Degradation rates were found to be pH dependent with greatest stability observed at pH 4. The reversible degradation of [6]-gingerol at 100°C and pH 1 was relatively fast and reached equilibrium within 2 h. Activation energies for the forward and reverse reactions for [6]-gingerol were calculated from the Arrhenius equation using reaction rates obtained at temperatures ranging from 37 to 100°C.

Racemic 6-gingerol can be obtained in a one-pot reaction by hexanal addition to the dianion of zingerone at low temperature. Similarly, addition of octanal or decanal to the dianion provides 8-gingerol or 10-gingerol, respectively. Acid treatment of the gingerols allows for formation of the corresponding shogaols.

When (3-(ethoxycarbonyl)-2-ethoxy-2-propenylidene)triphenylphosphorane (6) was allowed to react with α-bromo ketones 8a-d in dichloromethane in the presence of Cs2CO3 at room temperature, a annulation occured and led to the formation of the corresponding 2-ethoxycyclopentadienes 9a-d in excellent yields.Similarly, bromo thioester 8g underwent the annulation to give 4-(ethylthio)cyclopentadiene 9g.Secondary bromides 2-bromo-3-pentanone and 2-bromocyclohexanone also afforded tetrasubstituted cyclopentadienes 9e and 9f in moderate yields when 2 equiv of 6 was used.The annulation is belived to proceed through a sequence involving a stepwise alkylation at the γ position of 6 and an intramolecular Wittig reaction because of the fact that intermediate 11 was isolated.The resulting 2-ethoxycyclopentadienes 9a-g were converted quantitatively into the corresponding cyclopentenones 10a-g upon mild acid treatment.Furthermore, allylidenetriphenylphosphorane underwent a carbon elongation at both ends of the three-carbon unit via an alkylation-Wittig reaction sequence. (3-(tert-Butoxycarbonyl)-2-ethoxy-2-propenylidene)triphenylphosphorane (7) reacted first with alkyl halides and then with aldehydes in the presence of Cs2CO3 to give enol ethers 23a-f, which were converted into α,β-unsaturated ketones 20, 21, and 25c-f by hydrolysis of the enol ether and then decarboxylation.In this way, shogaol (29), the pungent principle component of ginger, was conveniently synthesized starting from 2-methoxy-4-methylphenol.

3-Alkoxycarbonyl-2-ethoxy-2-propenylidenetriphenylphosphorane reacts in turn with alkyl halides and aldehydes in the presence of base via a one-pot procedure to give moderate to good yields of conjugated enol ethers.Hydrolysis of the conjugated enol ethers and subsequent decarboxylation provide a novel route to α,β-unsaturated ketones.

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