- ON THE ASYMMETRIC INDUCTION INVOLVING LITHIUM ENOLATES OF 1-MENTHYLPROPIONATE
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The stereoselectivities of the reaction between 1-menthylpropionate 1 with LDA under standard kinetic conditions depend on the solvent.The Z-enolate 2a predominates in LDA/THF (Z/E=7.5/2.5) while the E-enolate 3a is the main product in LDA/THF/hexane (E/Z=8/2).The mixture of these enolates (E/Z=8/2) was allowed to react with allylbromide, benzaldehyde and MoOPH respectively.The higher ?-facial diastereoselection was obtained from MoOPH (d.e.=60percent).
- Ribeiro, Leny P.,Antunes, Octavio A. C.,Bergter, Lothar,Costa, Paulo R. R.
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- Highly diastereoselective reduction of (-) menthylphenylglyoxalate and (-) menthylpyruvate using new hindered lithiumtrialkoxyaluminohydrides
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Reduction of the keto group of (-) menthylphenylglyoxalate and (-) menthyl pyruvate can be achieved with high diastereoisomeric excess (80-90percent) using newly synthesized hindered lithium trialkoxyaluminium hydrides in THF at -78 deg C.Hindered borohydrides such as lithium trisiamylborohydride reduce those ketoesters with a lower diastereoselectivity.
- Boireau, G.,Deberly, A.
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- Menthol derivatives, mixture thereof, and preparation method and applications of menthol derivatives
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The invention discloses menthol derivatives, a mixture thereof, and a preparation method and applications of the menthol derivatives. Menthol carries out esterification reactions, then molecular design is performed to synthesize the menthol derivatives with a special molecular structure or a special group, and through the modification on the chemical structure, a novel material, which has a highermelting point and low volatility and is applied to temporary cultural relic reinforcement, is provided. The melting points of the menthol derivatives are gradient, the volatile speed of the menthol derivatives is slower than that of menthol, thus the removing of the menthol derivatives is controllable, and the requirements of cultural relic protection can be satisfied. The provided menthol derivatives are used to temporarily strengthen cultural relic onsite, and have a wide application range.
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Paragraph 0041; 0043; 0044; 0045
(2018/10/19)
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- Method for stabilizing menthyl lactate
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A method for stabilizing menthyl lactate is disclosed. The method comprises combining water with a solution comprising menthyl lactate and a water-miscible organic solvent in amounts effective to precipitate menthyl lactate from the resulting aqueous mixture. The aqueous precipitation method is simple to practice, and it provides menthyl lactate having remarkably improved storage stability.
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Page/Page column 6; 7
(2008/12/05)
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