# US 4,395,570 A · Preparation of 5-(2-halo-4-trifluoromethylphenoxy)-2-nitrobenzoic acid and salts and esters and amides

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- Number: US 4,395,570 A
- Document ID: US4395570A
- Status: Granted
- Kind: A
- Application number: 06/321,658
- Filed: 1981-11-16
- Granted: 1983-07-26
- Earliest claimed: 1981-11-16
- Assignees: Rohm and Haas Company
- Inventors: Colin Swithenbank
- Web page: https://patentgrep.com/patent/US4395570A

## CPC

- C07C 201/12: by reactions not involving the formation of nitro groups
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A process for preparing a substantially pure, isomer free 5-(2-halo-4-trifluoromethylphenoxy)-2-nitrobenzoic acid or its esters, salts and amides by the basic condensation of a 4-trifluoromethylphenol and a 1-chloro-3-substituted-4-nitrobenzene followed by halogenation. All known previous routes afforded, in addition to the desired product, a number of inactive isomers.

## Claims

### Claim 1

A process for preparing substantially pure and isomer free compound of the formula: ##STR3## wherein X.sup.1 is halo and R.sup.1 is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, carboxyalkyl, carbalkoxyalkyl, cyanoalkyl, alkoxyalkyl, haloalkyl, alkali metal or alakline earth metal cations, quaternary ammonium cations, amino, mono- R.sup.1 or di- R.sup.1 amino wherein R.sup.1 is as defined above which comprises reacting ##STR4## in the presence of an inorganic base in a polar solvent at a temperature in the range of from about 25.degree. to 90.degree. C. for from 1 to 18 hours to afford a substantially isomer free product of the formula: ##STR5## followed by treating said product with a halogenating agent in the presence of a Friedel-Crafts catalyst at at temperature in the range of from 50.degree. to 130.degree. C. for from 0.5 to 10 hours.

### Claim 2

A process for preparing substantially pure and isomer free compound of the formula: ##STR6## wherein X.sup.1 is halo and R.sup.1 is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, carboxyalkyl, carbalkoxyalkyl, cyanoalkyl, alkoxyalkyl, haloalkyl, alkali metal or alakline earth metal cations, quaternary ammonium cations, amino, mono- R.sup.1 or di- R.sup.1 amino wherein R.sup.1 is as defined above which comprises reacting ##STR7## in the presence of an inorganic base in a polar solvent at a temperature in the range of from about 25.degree. to 90.degree. C. for from 1 to 18 hours to afford a substantially isomer free product of the formula: ##STR8## followed by treating said product with a halogenating agent in the presence of a Friedel-Crafts catalyst at at temperature in the range of from 50.degree. to 130.degree. C. for from 0.5 to 10 hours and hydrolyzing said product to the free acid.

### Claim 3

A process for preparing substantially isomer free compound of the formula: ##STR9## wherein R.sup.' is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, carboxyalkyl, carbalkoxyalkyl, cyanoalkyl, alkoxyalkyl, haloalkyl, alkali metal or alkaline earth metal cations, quaternary ammonium cations, amino, mono- R.sup.1 or di- R.sup.1 amino wherein R.sup.1 is as defined above which comprises reacting ##STR10## wherein X' is halo, in the presence of an inorganic base in a polar solvent at a temperature in the range of from about 25.degree. to 90.degree. C. for from 1 to 18 hours to afford a substantially pure isomer free product.

### Claim 4

A process for preparing a substantially pure isomer free product of the formula: ##STR11## wherein X' is halo and R' is hydrogen, alkyl, alkenyl, alkynyl, hydroxyalkyl, carboxyalkyl, carbalkoxyalkyl, cyanoalkyl, alkoxyalkyl, haloalkyl, alkali metal or alakline earth metal cations, quaternary ammonium cations, amino, mono- R.sup.1 or di- R.sup.1 amino wherein R.sup.1 is as defined above which comprises treating a compound of the formula: ##STR12## with a halogenating agent in the presence of a Friedel-Crafts catalyst at a temperature in the range of from 50.degree. to 130.degree. C. for from 0.5 to 10 hours.

### Claim 5

A process for preparing 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitrobenzoic acid and its sodium salt which comprises treating p-hydroxybenzotrifluoride with methyl 3-chloro-4-nitrobenzoate and potassium carbonate in dimethyl sulfoxide at about 70.degree. C. for about 3 hours followed by treating the product obtained with chlorine gas in the presence of ferric chloride at about 70.degree. C. for about 2.5 hours, hydrolyzing the ester with an aqueous base to obtain sodium 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitrobenzoate which upon treatment with an inorganic acid affords 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitrobenzoic acid.