Preparation of fluorinated anilines

A compound, azobenzene technology, applied in the field of preparing fluorinated aniline, can solve problems such as unusable

Inactive Publication Date: 2005-07-13
SALTIGO GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this approach generally cannot be used when the nitrobenzene is more highly chlorinated or there are substituents t

Method used

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  • Preparation of fluorinated anilines
  • Preparation of fluorinated anilines
  • Preparation of fluorinated anilines

Examples

Experimental program
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Effect test

Embodiment 1

[0076] Preparation of 2,2',4,4',6,6'-hexafluoroazobenzene

[0077] In the absence of moisture, initially 4.3 g of dry potassium fluoride and 3.0 g of 2,2',4,4',6,6'-hexachloroazobenzene were added to 51 g of sulfolane, and 0.2 g of bromide Tetraphenylphosphonium. Subsequently, the mixture was heated to 180° C. and stirred for 12 hours. After cooling, the mixture was drained into 150 ml of water and extracted twice with 50 ml of cyclohexane (each). After crystallization, 1.7 g (76% of theory) of the desired product were obtained.

Embodiment 2

[0079] Preparation of 2,4,6-trifluoroaniline

[0080] 2,2',4,4',6,6'-hexafluoroazobenzene of 1.0g Example 1 was dissolved in 20ml methanol at room temperature, and 0.6g ammonium formate and 0.5g zinc powder were added continuously. The mixture was stirred at room temperature for 1 hour. The starting material was completely converted by GC analysis. After methanol had been distilled off, 2,4,6-trifluoroaniline was extracted in cyclohexane and dried, and the solvent was distilled off again. This leaves 0.9 g of the desired product (89% of theory).

Embodiment 3

[0082] Preparation of 2,2'-bis(trifluoromethyl)-4,4'-difluoroazobenzene

[0083] In the same manner as in Example 1, 9.8 g of 2,2'-bis(trifluoromethyl)-4,4'-dichloroazobenzene, 4 g of potassium fluoride and 0.5 g tetraphenylphosphonium bromide was reacted for 15 hours. After crystallization, 5.8 g of 2,2'-bis(trifluoromethyl)-4,4'-difluoroazobenzene (65% of theory) were obtained.

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Abstract

The present invention relates to a method for preparing fluorinated anilines from corresponding chlorinated anilines, and also relates to the application of fluorinated anilines.

Description

technical field [0001] The present invention relates to a method for preparing fluorinated anilines from corresponding chlorinated anilines, and also relates to the application of fluorinated anilines. technical background [0002] Fluorinated anilines are important intermediates for the preparation of active pharmaceutical ingredients and agrochemicals, as described in particular in WO-A98 / 46607 and WO 98 / 46608. [0003] Known methods for their preparation include, for example, nitration of fluorinated aromatic hydrocarbons and subsequent reduction of the nitro compound to the corresponding aniline. In this way, for example, 4-fluoroaniline and 2,4-difluoroaniline can be prepared from fluorobenzene and 1,3-difluorobenzene, respectively (see J.Org.Chem., 1962, 27, 1910- 11; J. Fluor. Chem., 2002 113(2), 207-9). The disadvantage of this method is that the fluorinated arenes are expensive and the nitration step allows only limited substitution patterns on the aromatic rings....

Claims

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Application Information

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IPC IPC(8): C07B61/00C07C209/42C07C211/52C07C245/08
CPCC07C209/42C07C211/52C07C245/08
Inventor M·米库拉斯A·马胡尔德
Owner SALTIGO GMBH
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