CS211396B2 - Method of making the derivatives of the 2,2-difluorbenzodioxole - Google Patents

Description

(54) A method for producing 2,2-difluorobenzodioxole derivatives

The invention relates to a process for the preparation of novel 2,2-difluorobenzodloxol derivatives which are used as starting materials for the preparation of insecticidally active benzyl esters containing ether and thioether residues which are substituted by fluorine.

It is already known that 2,2-difluorobenzodioxols can be obtained from 2,2-dichloro-benzodioxoles by reaction with antimolium fluoride [Ref. obšč. chim. 30 (1960) No. 9, 3129-3232]. However, this process is not technically feasible, since antimony trifluoride is very expensive and the method involves working in aqueous antimony trichloride solutions from which antimony trichloride can be recovered only at considerable cost.

The present invention relates to a process for the preparation of 2,2-difluorobenzodioxole derivatives of formula (I),

wherein n is 1 to 4 and

R ^{1 is the} same or different from the group consisting of hydrogen, C 1 -C 6 alkyl, tribailioigemethyl, C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 1 -C 6 alkylmercapto 6 carbon atoms, haloalkylmercapto of 1 to 6 carbon atoms of up to 6 halogen atoms, halogen, optionally substituted by a femyl, radical or phenloxy group, chlorocarbonyl, chlorosulfones left, nitro or two adjacent radicals together with an adjacent carbon atom form an optionally substituted benzene ring which consists in reacting compounds of formula II,

in which

R ^{1 and} n have the abovementioned meaning, with anhydrous hydrofluoric acid.

Preference is given to compounds of the formula I in which one radical R @ ¹ represents an alkyl group having 1 to 6 carbon atoms and the other radicals R @ ¹ represent the same or different radicals selected from the group consisting of hydrogen, C1 -C6 alkoxy, ha211396; (C 1 -C 6), (C 1 -C 6) alkyl, (C 1 -C 6) alkyl, (C 1 -C 6) haloalkylmercapto (C 1 -C 6) halogen, optionally substituted phenyl, or two adjacent radicals together with adjacent carbon atoms form optionally substituted a benzoidized benzene ring.

Very particularly preferred are compounds of formula I wherein one R ¹ represents a methyl group and the remaining radicals R ¹ are identical or different radicals from the group consisting of hydrogen or halogen.

The following compounds may be mentioned individually:

difluoro-3,4-dioxymethylenetoluene, difluoro-3,4-dioxymethylene-6-fluorotoluene, dlfluoro-3,4-dioxymethylene-6-chlorotoluene, difluoro-3,5-dloxymethylene-6-bromotoluene, difluoro-3,4-dioxymethylene-2,5,6-trichloro toluene, difluoro-3,4-dioxymethylene-2,5,6-trifluoroirtoluene, difluoro-2,3-dioxymethylentoluene.

Some of the starting materials of formula II are known. They can be produced from the appropriate benzo-dioxioles [J. Chem. Soc. 93, 566 (1908j), the corresponding pyrocateehinecarbomates [Chem. Ber. 96, 1382 (1963)] or from the corresponding pyrocatechinorthormate esters [Chem. Ber. 94, 544 (1961)] by reaction with phosphoic chloride.

Preference is given to starting materials of the formula II in which R @ ¹ represents the same or different radicals from the group consisting of hydrogen, C1 -C4 alkyl, such as methyl, ethyl, n-propyl, isopropyl, tert-butyll tirichloromethyl, fluorine, chlorine, bromine, phenyl optionally substituted by halogen, C 1 -C 4 alkyl, for example methyl, chlorocarbonyl, chlorosulfonyl, nitro or two adjacent R ¹ radicals together with adjacent atoms of carbon forms a condensed benzene ring.

Examples of starting materials of formula II are:

2, 2-dichloro-benzodioxole,

4-methyl-2,2-chloro-benzodioxole,

5-methyl-2,2-dichlorobenzodioxole-1,

5-ethyl-2,2-dichlorobenzodioxole,

5-p-propyl-2,2-dichlorobenzodiazole,

5-isopropyl-2,2-dichloro-benzodiole-Xot,

4-Methyl-2,2,5,6-tetra-chlorobenzodioxole

5-methyl-2,2,6-tfichlorbenzodioxol, 5-methyl-2,2,4,6-tetrachloirbenzodíaxol, 5-propyl-2,2,6-trichlOirbe nzodtoxol _l, 5-methyl-6-bromo-2, 2-Dichlorobenzodioxole, 5-fluoro-2,2-dichlorobenzodioxole-1, 5-bromo-2,2-dihydro-benziodioxole,

2,2,5-tirichlorobenzodioxole,

4-phenyl-2,2-dichlorobenzodioxole,

5-phenyl-2,2-dichlorobenzodioxole,

4-methoxy-2,2-dichloro or beododioxole,

5-methoxy-2,2-dichloro-bezo dioxole,

4-phenoxy-2,2-dichlorobenzodioxol,

5- (3 ‘-, methyl) -phenoxy-2,2-dichloro-benzodioxyl,

4- (4‘-nitro) phenoxy-2,2-dichlorobenzodioxole,

5-tert-butyl-2,2-dichlorobenzodioxole,

5-chloro-6-nitiro-2,2-dichlorobenzodioxoil,

2.2.4.6- tetrachloirbenzodioxole,

2.2.5.6- tetrachlorobenzodioxole,

5-methyl-2,2,4,6,7-pentachlorobinododioxole,

4-Chlorocarbonylbenzyl-2,2-dichlorobenzodioxole

_{5-chlorocarbonyl-l} phenyl-2,2 dichloirbenzodioxol 5-2,2-nitro' diehlorbemzadioxol, _{2R 2r-1} dichloirin aft'O-2,3-dioxQl,

2,2-diChloirna, fto-1,2-dioxol.

i jps *

This reaction can be carried out in the process according to the invention at temperatures from -20 ° C to 80 ^° C, particularly preferably from 0 ° C to + 40 ° C.

Hydrofluoric acid must be used at least in a stoichiometric amount, but the excess is generally favorable. Thus, the amount of hydrofluoric acid is preferably two to three times the stoichiometric amount, and the excess may be even greater. The reaction can be carried out in the presence of solvents as well as without solvents. Possible solvents are completely, generally inert, aprotic liquids. For example, methylene chloride, trichlorofluoromethane, carbon tetrachloride, chlorobenzene or nitrobenzene can be used successfully for the process according to the invention. The amount of solvent is of no importance for the process according to the invention. Thus, the reaction is preferably carried out without solvent if the starting materials are liquid.

In general, the reaction is carried out at atmospheric pressure, but can also be carried out at elevated pressure.

The process according to the invention can be carried out as follows:

The required amount of anhydrous hydrofluoric acid is introduced into the reaction vessel at a temperature of about -10 DEG C. and 2,2-dichloro-benzodioxole is added dropwise with stirring. The temperature is selected such that the evolution of hydrogen chloride occurs immediately and the resulting gas is passed through a reflux condenser to a charge, where it condenses or neutralizes. The temperature can be raised somewhat after the addition is complete. The reaction mixture is stirred until the gas evolves, and then excess hydrofluoric acid is distilled off under atmospheric pressure or under reduced pressure. The reaction product remains in the form of a residue which can be purified, for example, by distillation.

Compared to the known production method

This process has the advantage that it is easier to carry out and does not cause any environmentally harmful waste water. Further, the fluorinating agent used in excess can simply be regenerated and reused in the reaction.

The following examples illustrate the process according to the invention:

Example 1

4-Methyl-2,2-difluorobenzodi oxol

200 ml of hydrofluoric acid are introduced into the reaction vessel at 0 DEG C. and 100 g of 4-methyl-2,2-dichlorobenzodioxole are added dropwise. At the end of the hydrogen chloride evolution, the reaction mixture was heated to 20 ° C, stirred for 1 hour, and then excess hydrofluoric acid was distilled off under reduced pressure. 4-Methyl-2,2-difluorobenzodioxole has a boiling point at 1467 Pa of 42-45 ° C. Lolm index n _D ²⁰ = 1.4515. 4-Bromomethyl-2,2-difluorobenzodioixol boils at 93-96 ° C / 1333 Pa (n _D ²⁰ = 1.5115 µl).

Example 2

5-Propyl-2,2-difluorobenzodioxole

At-2 ° C, 100 rolls of anhydrous hydrofluoric acid are introduced into the reaction vessel, and then 110 g of 5-propyl-2,2-diohlorobenzothioxole are added dropwise. After analogous work-up as described in Example 4a, 67 g of 5-propyl-2,2-difluoroben, zodioxole having a boiling point of 80-83 ° C / 2000 Pa are obtained. Refractive index n _D ²⁰ = 1.4540.

Example 3

Difluoromethylene-3,4-dioxybenzoic acid

At -30 ^DEG C., 100 ml of anhydrous hydrofluoric acid is introduced, and then 55 g of 5-chloroic acid are added dropwise ^. rcarbonyl-2,2-diohlorobenzodioxole. After the addition was complete, the mixture was heated to 20 ° C and stirred until the evolution of hydrogen chloride was complete. Then, excess hydrofluoric acid is distilled off and the residue is stirred into 200 ml of 5% sodium hydroxide. The solution was filtered and then acidified with hydrochloric acid. Excluded

Claims (2)

SCOPE Difluoromethylene-3,4-dioxybenzoic acid is filtered off and dried. 35 g acid, mp 153-154 ^{O |} C. Example 4 2.2- Difluoirbemzodioxol aj 600 g of anhydrous hydrofluoric acid are introduced into the ViA reaction vessel, equipped with a stirrer, reflux condenser and dropping funnel, at -10 ° C. 612 g of 2,2-dichlorobenzodioxole are then added dropwise with the exclusion of moisture over a period of about 2 hours. The development of hydrogen chloride starts immediately. The gas is fed through the reflux condenser into the sample with water and absorbed. At the end of the addition, the temperature is raised to 18-20 ° C, and the mixture. Stirring is continued for 1 hour until gas evolution is complete. The excess hydrofluoric acid is now distilled off through the column and collected in a cooled sample. Thereafter, 394 g of 2,2-difluorobenzodioxole, b.p. Refractive index, n _D ²⁰ = 1.4430. Yield about _78/0 of theory. bj To 200 ml of anhydrous hydrofluoric acid in the reaction vessel from V4A was added dropwise a solution of 150 g of 2,2-di-chlorobenzisodiol in 200 ml of methylene chloride with stirring. The reaction is started immediately at 0 ° C. The mixture was allowed to react at 0 ° C, then the temperature was raised to 20 ^° C and stirred for an additional hour. Then excess hydrofluoric acid and solvent are distilled off under reduced pressure, and then 2,2-difluorobenzodioxole is distilled off. 85 g of product are obtained, corresponding to 68% of theory. Example 5 2.2-Difluoro-5-chlorobenzodioxole This compound is obtained in an analogous manner to that described in Example 4a j. Boiling point 57 ° C / 1866 Pa; Refractive index n _D ²⁰ = 1.4712. OF THE INVENTION A process for the preparation of 2,2-difluorobenzodiol oxole derivatives of the general formula I, ^O (I) wherein n is 1 to 4 and R ¹ mutually identical or different radical from the group consisting of hydrogen, alkyl .s 1 to 6 carbon atoms, trihalomethyl, alkoxy of 1 to 6 carbon atoms, halogenoalkoxy with from 1 to 6 carbon atoms and 1 to 6 halogen atoms, (C 1 -C 6) alkylmercapto, (C 1 -C 6) haloalkyl (C 1 -C 6) alkyl, halogen, optionally substituted, phenyl or phenoxy, chlorocarbonyl, chlorosulfonyl, nitro, or two adjacent radicals together with an adjacent carbon atom optionally form a substituted benzene ring, characterized by reacting a compound of formula (II) wherein: R ^{1 and} n have the abovementioned meaning, with anhydrous hydrofluoric acid.