Method for preparing 2-(2,3-dimethylphenyl)-1-propanal with chloroacetone

A technology of chloroacetone and propylmagnesium bromide, applied in the field of preparing 2--1-propanal, which can solve the problems of expensive, long time, and difficult to obtain

Inactive Publication Date: 2016-01-20
LONZA LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, these syntheses are time-consuming and expensive
and using rather expensive and not readily available starting materials

Method used

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  • Method for preparing 2-(2,3-dimethylphenyl)-1-propanal with chloroacetone
  • Method for preparing 2-(2,3-dimethylphenyl)-1-propanal with chloroacetone
  • Method for preparing 2-(2,3-dimethylphenyl)-1-propanal with chloroacetone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0231] Example 1: 2-(2,3-Dimethylphenyl)methyloxirane, compound of formula (XXII), metal substitution with butyllithium in THF

[0232] To a solution of 1-bromo-2,3-dimethylbenzene (0.27ml, 2.0mmol) dissolved in THF (4.0ml) was added n-butyllithium (2.0ml of 1.6M hexane solution, 3.2 mmol). The mixture was stirred at -78°C for 30 minutes, then a solution of chloroacetone (0.24ml, 3.0mmol) dissolved in toluene (0.42ml) was added dropwise over 20 minutes. The mixture was stirred at -78°C for 1 hour, then allowed to warm to room temperature. Analysis of a sample after 3 hours at room temperature showed the title epoxide to be the major reaction product. After stirring at room temperature for 3 days, the mixture was poured into water (20ml) and the product was extracted with ethyl acetate (1 x 10ml, 2 x 5ml). The combined extracts were washed with MgSO 4 Drying and concentration under reduced pressure afforded the title epoxide as an oil in quantitative yield.

[0233] 1 HNM...

Embodiment 2

[0235] Example 2: 2-(2,3-Dimethylphenyl)methyloxirane, compound of formula (XXII), metallized with magnesium in THF

[0236] To a suspension of magnesium (89 mg, 3.66 mmol) in THF (4.0 ml) was added NaH (81 mg, 60% in oil, 2.0 mmol) and after stirring at room temperature for 10 minutes, 1-bromo-2,3 - Dimethylbenzene (0.40ml, 2.96mmol). An exothermic reaction ensued and the resulting mixture was stirred at room temperature for 1 hour. The mixture was then cooled to -20°C and a solution of chloroacetone (0.26ml, 3.3mmol) dissolved in toluene (0.63ml) was added dropwise over 10 minutes. The mixture was then stirred at room temperature for 2 hours. The samples were worked up by mixing with water, extracting with ethyl acetate, evaporating the ethyl acetate with a stream of nitrogen. use 1 HNMR analysis of the residue showed it to be a mixture of xylenes and the title oxirane compound.

Embodiment 3

[0237] Example 3: 2-(2,3-Dimethylphenyl)propanal, compound of formula (XXI)

[0238] The 2-(2,3-dimethylphenyl)methyloxirane prepared according to Example 1, the compound of formula (XXII) (158mg, 0.97mmol) was dissolved in toluene (1.57mL), and at room temperature Join BF under 3 OEt 2 (0.006ml, 0.05mmol). After 2 hours at room temperature the sample was mixed with solid NaHCO 3 Mix, filter, concentrate under reduced pressure, use 1 The residue was analyzed by HNMR. The crude product consisted essentially of pure 2-(2,3-dimethylphenyl)propanal.

[0239] 1 HNMR: 1.40(d, J=7.1Hz, 3H), 2.25(s, 3H), 2.32(s, 3H), 3.89(qd, J=7.1, 1.0Hz, 1H), 6.89 to 6.92(m, 1H) , 7.12 (m, 2H), 9.67 (d, J=1.0Hz, 1H).

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Abstract

The invention discloses a method for preparing 2-(2,3-dimethylphenyl)-1-propanal by using 1-bromo-2,3-dimethylbenzene and chloroacetone as starting materials. Use in fragrances and its use in the preparation of medetomidine.

Description

technical field [0001] The invention discloses a method for preparing 2-(2,3-dimethylphenyl)-1-propanal by using 1-bromo-2,3-dimethylbenzene and chloroacetone as starting materials. Use in perfumery, and its use for the preparation of medetomidine. Background technique [0002] Aromatic aldehydes are widely used as flavorings and essences in cosmetics, fragrances, and many household products. α,β-Unsaturated aromatic aldehydes such as substituted cinnamaldehydes are known to have distinctive aromas and are therefore used in the fragrance industry. [0003] WO98 / 45237A discloses certain aromatic aldehydes, a process for their preparation starting from acetophenone acetals, their use as perfumes, and their use as intermediates for the preparation of 3-arylpropionaldehydes . They have a musky fragrance. [0004] The fragrance and houseware industry has a constant demand for new fragrances with interesting, new and as yet unavailable aromas, to increase the selection of frag...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C45/51C07C45/58C07C47/228C07D303/02
CPCC07C45/511C07C45/58C07D233/58C07D301/02C07D303/04C07C47/228C07D233/56C07D301/26C07C45/51C07C49/11C07C49/213C07D303/02C07C25/125
Inventor 弗洛伦斯奥·萨拉戈萨道尔沃德安娜·库勒撒史蒂芬·埃琳娜罗伯特·布约克兹比格纽·沃贝克里斯托弗·沃伊切霍夫斯基
Owner LONZA LTD
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