LT3919B - Process for the preparation of 2,5-dichlorophenol derivatives - Google Patents

Abstract

2,5-Dichlorophenol derivatives of formula (I): wherein R 3 is -NH 2 or -N = C = O obtained from the phenol of formula (II): (II). wherein the amino group is pre-acylated in reaction with hexafluoropropene. Formula (I), if necessary, is obtained a compound wherein R 3 is -NH 2, is treated with phosgene, and a compound of formula (I) wherein R 3 is -N = C = O.

Description

2,5-Dichlorophenol derivatives of formula (I):

Cl where R ₃ is -NH ₂ or -N = C = O is obtained for the phenol of formula (II):

(II).

the amino group of which is pre-acylated by reaction with hexafluoropropene. Optionally, the resulting compound of formula (I) wherein R ₃ is -NH ₂ is treated with phosgene to give a compound of formula (I) wherein R ₃ is -N = C = O.

This invention relates to the preparation of a novel compound of formula (I):

Cl ch ₃ -chp-c? ₂ -o-Cl (I), where -NH ^ or -N = £ L = O.

More specifically, the present invention relates to 2,5-dichloro-4- (1,1,2,3,3,3,3-hexafluoropropyloxy) -aniline (R 1 -NH 4) and 2,5-dichloro-4- (1, 1,2, 3 »3» 3-hexafluoropropyloxy) -phenyl isocyanate / Ry=-N=.C=O/.

Both of these compounds are used as starting materials for the synthesis of potent pesticidal activity benzoyl ureas according to the patent application no. 3963351/04 basis.

The essence of the proposed process is that the phenol of formula II

wherein the amino group is pre-acylated, reacted with hexafluoropropene and optionally treated with a compound of formula I wherein R 1 represents -NHg, treated with phosgene to give a compound of formula I wherein R 6 represents a -N = C = O group.

EXAMPLE

a) Preparation of 2,5-dichloro-4- (1,1,2,3,3,3,3-hexafluoropropyloxy) aniline g of 4-acetylamino-2,5-dichlorophenol in an autoclave with 154 g of 90% potassium alkali and 130 ml dimethylformamide. Subsequently, 75.8 g of hexafluoropropene were pumped into a closed autoclave under pressure. The mixture was stirred for 20 hours at 70 ° C and at a pressure that was stable in the reactor. After cooling, the mixture was concentrated in a rotary evaporator and the residue was dissolved in methylene chloride. The resulting solution was washed with water, dried over sodium sulfate and concentrated. The crude product was obtained as a residue which was purified by chromatography on silica gel columns (length: 1 m, diameter: 10 cm) eluting with a mixture of toluene and acetone (11: 1). As a result, 4-acetylamino-2,5-dichloro- (1,1,2,3,3,3,3-hexafluoropropyloxy) -benzene was obtained in the form of pale yellow crystals (melting point 93-95 ° C). 26 g of these crystals were refluxed in 1Q vaLT 3919 B with 110 ml of ethanol and 35.6 ml of 37% hydrochloric acid. The reaction mixture was then concentrated, diluted with ice / water and basified to a slightly alkaline reaction. The product was extracted from the mixture with methylene chloride. The organic phase of the extract was washed with water, dried over sodium sulfate and concentrated. The residue was purified by distillation to give the title compound as a colorless liquid, m.p. 81-83 ° C at 0.05 torr.

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b) Preparation of 2,5-dichloro-4- (1,2,3,3,3-hexafluoropropyloxy) -phenyl isocyanate.

To 95 ml of a 20% (w / w) solution of phosgene in toluene and 200 ml of ethyl acetate were added dropwise 16.4 g of 2,5-dichloro-4- (l, 1 »2, 3» 3 »3) at 20-25 ° C. hexafluoropropyloxy) -aniline in 100 ml of ethyl acetate.

The reaction mixture was then stirred at room temperature for 5 hours, and then refluxed for another two hours. The mixture was then concentrated in vacuo and distilled in a deep vacuum. The title compound was isolated in the form of an oil having a boiling point of 95 ° C at a pressure of 0.01 torr.

Claims (1)

DEFINITION OF INVENTION A process for the preparation of a 2,5-dichlorophenol derivative of formula (I) -r ₃ fi) wherein R 4 represents -NH 8 or -N = C = O, wherein the phenol of formula (II): C1 - nh ₂ f II), / Wherein the amino group is pre-acylated, reacts with hexafluoropropene and, if necessary, reacts the resulting compound of formula (I) wherein R ^ represents -NH ^ with phosgene to give a compound of formula (I) wherein R ^ represents N = C = O.