HU177082B - Process for producing halogen-containing epoxydes - Google Patents

Description

The present invention relates to a process for the preparation of epoxypentane derivatives of general formula (I). In the formula, Y represents a chlorine or bromine atom, X represents a halogen atom or a single bond with Z and Z represents a hydrogen atom or a single bond with X.

The compounds of the present invention are novel intermediates for the preparation of synthetic pyrethroids. Synthetic pyrethroids are active substances of the high-potency insecticides and acaricides.

Several methods have been described in the literature for the preparation of ethyl esters of 2,2-dimethyl-3- (2,2-dihalo-vinyl) -cyclopropanecarboxylic acids (Synthetic Pyrethroids, p. 45, ÁCS Symposium Series, Am. Chem. Soc. Washington, 1977). )

By dehydrochlorination of aliphatic oligomeric chlorohydrines, the corresponding epoxides can be prepared (U.S. Pat. Nos. 416,368 and U.S. Pat. No. 2,918,479), resulting in mixtures of materials.

The process of the present invention provides novel intermediates from which 2,2-dimethyl-3- (2,2-dihalo-vinyl) -cyclopropanecarboxylic acids and their biologically active esters are also prepared.

The present invention relates to a process for the preparation of epoxy-pentane derivatives wherein Y is a chlorine or bromine atom,

X is chlorine or bromine, or Z is a single bond and

Z represents a hydrogen atom or a single bond together with X such that a pentanol derivative - wherein Y is as defined above in Formula II

(a) with alkali hydroxide in the presence of a C 1 -C 4 alkanol; or

b) C 1 -C 4 alkali alcoholate in the presence of C 1 -C 4 alkanol; or

c) ammonium or phosphonium salts with alkali hydroxide as water and phase transfer catalysts having R ¹ , R ² , R ³ and R ⁴ alkyl or aralkyl groups in the formula (III),

The nitrogen or phosphorus atom and B in the presence of chlorine or bromine are reacted at 0-100 ° C.

Depending on the temperature used, different epoxypentane derivatives are obtained. When the reaction temperature is 0-30 ° C, 5-trihalopentane derivatives are obtained, while at 40-80 ° C, 5-dichloropentene derivatives (V) are obtained. Thus, in the first case, 1 and 2 molecules of halogenohydrogen are eliminated.

The starting material of the process of the invention is preferably 2-methyl-3,5-tetrachloropentan-2-ol.

In one embodiment of the process of the invention, an alkali hydroxide, preferably sodium or potassium, of 17

hydroxide is used in the presence of a C 1 -C 4 alkanol such as methanol or ethanol. Alternatively, C 1-4 alkali alcohol, preferably sodium or potassium ethylate or sodium or potassium methylate, is preferably employed in the presence of an alkanol having the same number of carbon atoms as the alkali alcohol. In the third process variant, the alkali metal hydroxide, preferably sodium or potassium hydroxide, is used in the presence of water and a phase transfer catalyst of the formula (III) wherein the substituents are as defined above. The concentration of the alkali hydroxide used is preferably 10-50% by weight. Both ammonium and phosphonium salts are suitable as phase transfer catalysts. In the general formula (III), the substituents R ¹ , R ² , R ³ and R ^{4 can} be both lower and long chain, identical or different alkyl or aralkyl groups. For example, the following compounds are preferably used as phase transfer catalysts: tricaprylmethylammonium chloride, triethylbenzylammonium chloride, tetrabutylammonium chloride, trimethylhexadecylphosphonium bromide. The amount of phase transfer catalyst used is preferably 2 to 10% by weight, based on the starting material (II).

Depending on the reagents used, the final product can be recovered from the reaction mixture in various ways. Preferably, the alkali halide which may be precipitated is removed by filtration. In a two-phase system, the phases can preferably be separated before being further processed. The solvent from the final product phase is preferably removed by distillation. The final product may be purified by fractional distillation under reduced pressure.

The invention is illustrated by the following examples, which are not intended to limit the scope of the invention.

Example 1

24.0 g of 2-methyl-3,5-tetrachloropentan-2-ol are added dropwise to 30.0 g of 40% w / w aqueous sodium hydroxide containing 0.5 g of tricaprylmethylammonium chloride catalyst. The reaction mixture was stirred at 25 ° C for 2 hours, the organic phase was separated and evaporated under reduced pressure.

Yield: 16.5 g of 2-methyl-2-epoxy-5-trichloropentane Boiling point: 82-84 ° C (15 torr ηθ ⁵ = 1.4762 NMR (CCl ₄ )): Me 1.33s (3H), l, 36s (3H), 2.9-3.15 m CH = CH ₂ (3H)

In the same manner as in Example 1, the following catalysts were used: Example: Catalyst: Production: Second of triethyl benzyl ammonium chloride 68% Third tetrabutylammonium chloride 79% 4th trimethyl hexadecyl phosphonium bromide 75%

Example 5

24.0 g of 2-methyl-3,5-tetrachloropentan-2-ol are added dropwise to a solution of 4.0 g of sodium hydroxide in 100 ml of methanol at 5-10 ° C.

The reaction mixture was stirred for 1 hour, the precipitated sodium chloride was filtered off, the methanol was removed from the filtrate under normal pressure, and the residue was fractionated in vacuo. 14.2 g of 2-methyl-2-epoxy-5-tricyclopentane are obtained.

Boiling point: 86-89 ° C / 17 torr, n ^ ⁵ = 1.4755,

Example 6

In each case, the procedure was as in Example 5, but using 100 ml of 1 M alcoholic sodium alcohol as the base. 14.2 g of 2-methyl-2-epoxy-5-trichloropentane are obtained.

Boiling point: 82-84 ° C / 15 torr, n, = 1.4760,

Example 7

24.0 g of 2-methyl-3,5-tetrachloropentan-2-ol are added to 50 g of 50% aqueous sodium hydroxide solution containing 0.5 g of tricaprylmethylammonium chloride. The reaction mixture was stirred at 60 ° C, the organic phase was separated and evaporated under reduced pressure.

Yield: 11.5 g (69%) of 2-methyl-2-epoxy-5-dichloropentene-4.

B.p. 59-61 ° C / 15 torr, n, -, ^δ = 1.4830, NMR (CCl ₄ ) δ: Me 1.38s (3H), 1.44s (3H),> CH 3.48d (1H) ), CH = 5.82d (1H) J = 7Hz

Example 8

1-Methyl-3,5-tetrachloropentan-2-ol (24.0 g, 0.1 mol) was added dropwise to a solution of potassium hydroxide (12.0 g, 0.11 mol) in ethanol (100 ml) and refluxed for 3 hours. The precipitated potassium chloride is filtered off, the alcohol is distilled off under normal pressure and the residue is fractionated in vacuo.

Yield: 10.1 g (60%) of 2-methyl-2-epoxy-5-dichloropentene-4.

Boiling point: 62-65 ° C / 17 torr, ^m / z - 1.4812

Claims (3)

Patent claims: A process for the preparation of epoxypentane derivatives wherein Y is a chlorine or bromine atom in the general formula (I) X is chlorine or bromine, or Z is a single bond and Z represents a hydrogen atom or a single bond together with X, characterized in that a pentanol derivative - in which in formula (II) Y represents an alkali hydroxide (a) in the presence of a C 1-4 alkanol, or (b) C 1 -C 4 alkali alcohol in the presence of C 1 -C 4 alkanol, or c) with an alkali hydroxide in the presence of water and a phase transfer catalyst in the presence of ammonium or phosphonium salts of the formula (III): R, R ² 'R ³ and R ¹ ' 12 C 24 alkyl or aralkyl, The nitrogen or phosphorus atom and B the chlorine or bromine atom are reacted at 0-100 ° C. Process for the preparation of process variant a), b) or ej according to claim 1 for the preparation of 2-methyl-2-epoxy-5-trihalogenopentane derivatives, characterized in that the compounds are 0-30 ° C. Reaction temperature. 3. A process for the preparation of a process variant j, bj or ej according to claim 1 for the preparation of 2-methyl-2-epoxy-5-dihalopentene derivatives, characterized in that the compounds are prepared at 40-80 ° C. 10.