Catalyst for preparing L-menthol intermediate d-citronellal and preparation method thereof

An intermediate, citronellal technology, which is applied in the field of medicine, can solve the problems of cumbersome recycling process, high operation and equipment requirements, and achieve the effect of avoiding the difficulty of catalyst recycling, reducing production costs, and major innovations

Active Publication Date: 2013-09-04
上海统益生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the recovery process of the chiral catalyst is very cumbersome. Since the catalyst is a homogeneous catalyst, it needs to be concentrated under reduced pressure to remove the solvent, and then the product is distilled. Air and oxygen have high requirements on operation and equipment. In the early stage of the catalyst application experiment, we found that the loss of a single batch reached 10%, and the total TON value could only reach 80,000.

Method used

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  • Catalyst for preparing L-menthol intermediate d-citronellal and preparation method thereof
  • Catalyst for preparing L-menthol intermediate d-citronellal and preparation method thereof
  • Catalyst for preparing L-menthol intermediate d-citronellal and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Catalyst preparation:

[0046] Under nitrogen protection, [Rh(COD)Cl] 2 (500mg, 1mmol) was dissolved in 20ml of dry tetrahydrofuran, 1,5-cyclooctadiene COD (0.54ml, 4mmol) was added, and the reaction solution was stirred for 5 minutes, then AgClO 4 (420mg), react at room temperature for 1 hour;

[0047] Under the protection of nitrogen, add PS-BINAP (2.58g) to the above reaction solution, replace nitrogen with hydrogen, keep 3atm hydrogen pressure, stir at room temperature, and detect the reaction by thin layer chromatography until PS-BINAP no longer decreases, about 12 Hour. Stop the reaction, slowly add dry toluene, and then place the reaction bottle in a refrigerator at 0°C for crystallization. After removing the solvent, wash with a small amount of toluene, and dry in vacuo to obtain 2.15 g of red crystals, which is the chiral catalyst, with a yield of 80%.

[0048] The chemical structural formula is as follows:

[0049] [Rh(PS-Binap) 2 ] + [ClO 4 ] -

[0...

Embodiment 2

[0054] Embodiment 2 catalyst preparation

[0055] Under nitrogen protection, [Rh(COD)Cl] 2 (500mg, 1mmol) was dissolved in 20ml of dry dichloromethane, and 1,5-cyclooctadiene COD, (0.54ml, 4mmol) was added. After the reaction solution was stirred for 5 minutes, AgBF was added 4 (430mg), reflux reaction for 1 hour, the above reaction solution was added to PS-BINAP (2.58g), nitrogen was replaced with hydrogen, kept under 1atm hydrogen pressure, stirred at room temperature, TLC detection reaction, until PS-BINAP no longer reduced, After about 5 hours, the reaction was stopped, dry ether was slowly added, and then the reaction bottle was placed in a refrigerator at 0°C for crystallization.

[0056] After the solvent was removed, it was washed with a small amount of toluene and dried in vacuo to obtain 2.20 g of red crystals with a yield of 82%.

[0057] The chemical structural formula is as follows:

[0058] [Rh(PS-Binap) 2 ] + [BF 4 ] -

[0059] Characterized by melting ...

Embodiment 3

[0063] The preparation of embodiment 3 geranylamine

[0064]

[0065] Add the catalyst of Example 1 into a dry 100 mL reactor with sealed tubes, and replace the system with dry high-purity nitrogen for 3 times. Then add tetrahydrofuran and geranylamine, seal the system, heat it to 100°C, and continue the heat preservation reaction for 15 hours. After the reaction is completed, cool the system to room temperature, and then recover the solvent from the reaction solution under a reduced pressure of 400 Torr, and then filter to remove the catalyst. The remaining liquid It was directly used in the next reaction without purification. The catalyst was recovered by filtration, washed and weighed dry, with a loss of 0.5%.

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Abstract

The invention discloses a catalyst for preparing an L-menthol intermediate d-citronellal and a preparation method thereof. The catalyst is characterized in that the structure is [Rh(PS-Binap)2]<+>Y<->, wherein Y<-> is ClO4<->, PF6<-> or BF4<->; and Bingap is (-)-2,2'-bis-(diphenylphosphine)-1,1'-binaphthyl. The catalyst has very excellent physicochemical properties. When the catalyst is subjected to asymmetric hydrogen migration, myrcene amine can be basically obtained by utilizing a quantitative method, and nearly optically-pure d-citronellal can be obtained by carrying out simple acidic hydrolysis on the myrcene amine. The d-citronellal obtained by utilizing the method does not need to be purified and can be subjected to cyclization and high-pressure hydrogenation to produce a target product L-menthol.

Description

technical field [0001] The invention belongs to the technical field of medicines, and relates to a catalyst for preparing d-citronellal, an important intermediate of L-menthol. Background technique [0002] L-menthol, also known as L-menthol, its chemical name is (1R,2S,5R)-2-isopropyl-5-methyl-1-cyclohexanol, its English name is L-menthol, and its structural formula is as follows : [0003] [0004] (1) [0005] L-menthol is a cyclic monoterpene alcohol structure substance with very obvious physiological activity, and it is widely used in medicine. Secondly, L-menthol is one of the spices with the largest demand in the world. It can be used as tobacco flavor and toothpaste essence; menthol can also be used as a flavoring agent for various foods. In addition, a large amount of L-menthol is an important raw material for the synthesis of menthyl lactate, menthylamide, lamivudine and other substances. Now the acquisition of L-menthol is mainly through two ways, one is to...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J31/24C07C47/21C07C45/00
CPCY02P20/582
Inventor 金燕华张伟强
Owner 上海统益生物科技有限公司
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