# US 5,705,674 A · Process for preparing ortho-nitrobenzonitriles

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- Number: US 5,705,674 A
- Document ID: US5705674A
- Status: Granted
- Kind: A
- Application number: 08/698,792
- Filed: 1996-08-16
- Granted: 1998-01-06
- Earliest claimed: 1995-08-16
- Assignees: Hoechst Aktiengesellschaft
- Inventors: Thomas Wessel; Peter Koch
- Web page: https://patentgrep.com/patent/US5705674A

## CPC

- C07C 253/14: by reaction of cyanides with halogen-containing compounds with replacement of halogen atoms by cyano groups
- C07C 255/50: to carbon atoms of non-condensed six-membered aromatic rings
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

The present invention relates to a process for preparing ortho-nitrobenzonitriles of the formula I, ##STR1## where R.sup.1 and R.sup.2 are as defined in claim 1, by reacting the corresponding ortho-fluoronitrobenzenes with alkali metal cyanides or cyanide-donating substances in the presence of phase transfer catalysts.

## Claims

### Claim 1

A process for preparing an ortho-nitrobenzontrile of the formula I, ##STR6## where R.sup.1 and R.sup.2, which can be identical or different, are hydrogen or electron--withdrawing groups, which comprises reacting the corresponding ortho-fluoronitrobenzene of the formula II, ##STR7## where R.sup.1 and R.sup.2 are as defined for the formula I, with an alkali metal cyanide or a cyanide-donating substance, wherein the reaction is carried out in an aqueous medium in the presence of a phase transfer catalyst.

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein R.sup.1 and R.sup.2 are, independently of one another, hydrogen, nitro, (C.sub.1 -C.sub.4)-alkylsulfonyl, halo-(C.sub.1 -C.sub.4)-alkylsulfonyl, cyano, carboxy, ((C.sub.1 -C.sub.4)-alkyl)oxycarbonyl, pentafluoroethyl or methyl monosubstituted, disubstituted or trisubstituted by halogen.

### Claim 3 (depends on 1)

The process as claimed in claim 1, wherein one of the radicals R.sup.1 and R.sup.2 is hydrogen and the other is trifluoromethyl.

### Claim 4 (depends on 1)

The process as claimed in claim 1, wherein the ortho-nitrobenzonitrile prepared is 2- nitro-4-trifluoromethylbenzonitrile.

### Claim 5 (depends on 1)

The process as claimed in claim 1, wherein the reaction is carried out using sodium or potassium cyanide.

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein the cyanide-donating substance used is a cyanohydrin of the formula III ##STR8## where R.sup.3 is hydrogen or a straight-chain or branched alkyl group, and R.sup.4 is a straight-chain or branched alkyl group which can be the same as or different than the alkyl group of R.sup.3.

### Claim 7 (depends on 6)

The process as claimed in claim 6, wherein R.sup.3 and R.sup.4 are a (C.sub.1 -C.sub.8)-alkyl group.

### Claim 8 (depends on 6)

The process as claimed in claim 6, wherein R.sup.3 and R.sup.4 are both methyl.

### Claim 9 (depends on 1)

The process as claimed in claim 1, wherein the phase transfer catalyst is a salt of a quaternary nitrogen compound or phosphonium compound.

### Claim 10 (depends on 9)

The process as claimed in claim 9, wherein the phase transfer catalyst is a tetra(n-butyl)ammonium salt or tetra(n-butyl)phosphonium salt.

### Claim 11 (depends on 10)

The process as claimed in claim 10, wherein the phase transfer catalyst is the hydrogen sulfate salt of tetra(n-butyl)ammonium or the bromide salt of tetra(n-butyl)phosphonium.

### Claim 12 (depends on 1)

The process as claimed in claim 1, wherein the phase transfer catalyst is a compound having crown ether properties.

### Claim 13 (depends on 12)

The process as claimed in claim 12, wherein the phase transfer catalyst is tris(3,6-dioxaheptyl)amine.

### Claim 14 (depends on 1)

The process as claimed in claim 1, wherein the reaction is carried out in a purely aqueous medium without addition of an organic solvent.

### Claim 15 (depends on 1)

The process as claimed in claim 1, wherein the reaction is carried out at a pH of from 7 to 12.

### Claim 16 (depends on 1)

The process as claimed in claim 1, wherein the reaction is carried out at a temperature of from 0.degree. C. to 100.degree. C.