FI65989B - FOER FARING FRAMSTAELLNING AV ALFA-CYANBENSYLKARBOXYLATESTER - Google Patents

Description

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Patent- j * nkiitorthiJIitw .... ________________ hM. ^. «MH- (M) HUX.« IN 30.04.84 (32) (33) (31) Requested «at that time — BugM prlorttat 01 .03 · 76 OI.O3 .76, OI.O3.76 Engl anti-England (GB) 8044/76, 8045/76, 8046/76 (71) Shell Internationale Research Maatschappij BV,

Carel van Bylandtlaan 30, The Hague, Hoilanti-Hoiland (NL) (72) Roger Arthur Sheldon, Amsterdam, Peter Been, Amsterdam,

Hoilanti-Hoi land (NL), Derek Alexander Wood, Sittingbourne,

Kent, Ronald Frank Mason, Ashford, Kent, England-England (GB) (7¾) Oy Kolster Ab (5¾) Method for the preparation of 0 <cyanobenzylcarboxylate ester -Förfarande för framstälIning av cx-cyanobenzylcarboxylatester for the preparation of plant-active esters of the type "synthetic pyrethroid".

According to DE-A-2 231 312, certain synthetic pyrethroids can be prepared by reacting a substituted cyclopropanecarbonyl halide with a 3-substituted benzaldehyde in the presence of an aqueous solution of sodium or potassium cyanide. This method yields pyrethroids of the type.

It has now been found that the yield of the ester of formula I as well as other esters belonging to the group of "synthetic pyrethroids" can be improved and prepared more efficiently by using a certain catalyst.

2 6 3 9 8 9

The invention relates to a process for the preparation of * -cyanobenzylcarboxylate ester of the general formula

/ A

?OF

R.CO.O-CH -------- ^> II

wherein R is an alkyl group optionally substituted by a halogen-substituted phenyl group, or a cycloalkyl group optionally substituted by one or more alkyl, alkenyl or haloalkenyl groups having up to 8 carbon atoms, and A is phenoxy, phenylthio or benzyl, with the formula

A

OCH ----- ζ \ III

to react with an acyl halide of the formula R-CO-Hal (where Hal is bromide or chloride) in the presence of water, a water-soluble cyanide and a substantially water-immiscible aprotic solvent.

The process according to the invention is characterized in that the reaction is carried out in the presence of a phase transfer catalyst.

As the phase transfer catalyst, any reagent capable of accelerating the reactions between the phases of two-phase systems consisting of water and an organic solvent can be used.

The phase transfer catalyst may be an onium compound, in particular a quaternary onium compound of the general formula | - R1 + R2-X-R4 Y-R3, in which X is a nitrogen, phosphorus or arsenic atom, R, R, R and R are alkyl, aralkyl, alkylaryl or aryl groups and Y is a monovalent ion, e.g. a halide such as chloride, bromide or iodide, or an alkyl sulphate, e.g. methyl sulphate or ethyl sulphate, or of the general formula 3 65989 6 + r5-s-r7 y " A sulfonium compound according to L, wherein R, R and R are alkyl groups and Y is a monovalent ion, e.g. a halide such as chloride, bromide or iodide, or an alkyl sulphate, e.g. methyl sulphate or ethyl sulphate, Preferably the alkyl groups contain from 1 to 18 carbon atoms. and aralkyl and alkylaryl groups up to ten carbon atoms, Preferably the aryl group is phenyl.

Examples of suitable onium compounds are tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, methyltri-2-methylphenylammonium chloride, tetramethylphosphonium iodide, tetra-n-butylphosphonium bromide, methyltriphenylarsonium, methyltriphenylarsonium n-hex-dekyylidimetyylisulfoniumjodidi. Very good results have been obtained with quaternary ammonium compounds.

The onium compound may be a hydroxide or a salt and may be used as a functional moiety in a strongly basic anion exchange resin formed by a moiety (polymer matrix) and a moiety (ionic group). Of particular importance are polystyrene resins, e.g. copolymers of aromatic monovinyl compounds and aromatic polyvinyl compounds, and in particular styrene-divinylbenzene copolymers. The functional moiety is a quaternary ammonium, phosphonium or arsonium group. Examples of useful strongly basic ion exchange resins are those derived from trimethylamine (e.g. under the tradename Amberlite IRA-400, Amberlite IRA-401, Amberlite IRA-402, Amberlite IRA-900, Duolite A-101-D, Duolite 1-ES, 111, Dowite ES-111, Dowex 11, Dowex 21K and Ionac A-450) and derived from dimethylethanolamine (e.g. under the tradename Amberlite IRA-410, Amberlite IRA-911, Dowex 2, Duolite A-102-D, Ionac A-542 and Ionac A-550).

Very good results have been obtained with ion exchange resins derived from trimethylamine.

Other suitable phase transfer catalysts include macrocyclic polyethers known as "crown ethers". These compounds and their preparation have been described in the literature, e.g., Tetrahedron 65989 4

Letters, No. 18 (1972), pp. 1793-1796 and are generally named by the total number of atoms forming the macrocyclic ring and the number of oxygen atoms in that ring. Thus, a macrocyclic polyether having the formal chemical name 1,4,7,10,13,16-hexaoxacyclooctadecane is referred to as "18-crown-6". Other examples of suitable macrocyclic polyethers are 3,4-benzo-1,6,9,12,15,18,21-heptaoxacyclotricos-3-ene and 3,4-benzo-1,6,9,12-tetraoxacyclotetradec-3-ene. ene. Especially recommended is the 18-crown-6.

Other suitable phase transfer catalysts include surfactants. "Surfactant" is defined as in Kirk-Othmer, "Encyclopenia of Chemical Technology", second edition, volume 19 (1969), p. 508: "An organic compound in which the same molecule has two different structural groups, one being water-soluble and the other insoluble in water ".

Preferably, the surfactant is a non-ionic, e.g. poly (alkyleneoxy) derivative formed by reacting a higher alcohol, alkylphenol or fatty acid with ethylene oxide or propylene oxide. Suitable alcohols, alkyl phenols or fatty acids contain an alkyl group of 8 to 20 carbon atoms and have 1 to 50 alkyleneoxy units. A particularly suitable nonionic surfactant (in the examples as "Dobanol 91-6") consists of a C8-C18-n-alkanol mixture and contains an average of six ethyleneoxy units. The nonionic surfactant may be an alkylbenzene having a direct alkyl group. The alkyl group of suitable alkylbenzenes has 8 to 20 carbon atoms.

The molar ratio of phase transfer catalyst to benzaldehyde of general formula III can vary within wide limits, but is preferably from 1: 5 to 1: 500. The use of lower molar ratios requires a longer reaction time. Of course, the use of higher molar ratios increases the cost of ester production. Thus, the choice of reaction time and the molar ratio of catalyst to benzaldehyde depend on each other and in each individual case the local economic factors are decisive. In general, good results are obtained with a molar ratio of 1:10 to 1: 100.

The process of the invention has a molar ratio of acyl halide (R-CO-hal) to benzaldehyde of 1: 1 or slightly higher. Preferably, the molar ratio is 1.1: 1.0 to 1.0: 1.0.

65989

The molar ratio of water-soluble cyanide to aromatic aldehyde is preferably 1.5: 1 to 1.0: 1.0 and most preferably 1.3: 1 to 1.02: 1.00. The term "water-soluble cyanide" means a water-soluble salt of hydrogen cyanide. Preferred water-soluble cyanides are alkali metal and alkaline earth metal cyanides. Sodium cyanide is particularly preferred because it provides esters of general formula II in the shortest reaction time.

Most preferably the temperature of the process is above 0 ° C and preferably from 10 to 50 ° C. Very good results have been obtained at a temperature of 15-40 ° C. The advantage of the method is that the ambient temperature is very suitable.

Examples of suitable almost completely water-immiscible aprotic solvents are alkanes, cycloalkanes or mixtures thereof, and particularly suitable are n-hexane, n-heptane, n-octane, n-nonane, n-decane and their isomers (e.g. 2-methylpentane, 3-methylpentane, 2-methylhexane, 3-methylhexane and 2,4,4-trimethylpentane), cyclohexane and methylcyclohexane. Alkane-rich gasolines are also very suitable; their boiling range is at normal pressure e.g. 40-65 ° C, 60-80 ° C or 80-110 ° C. Very good results have been obtained with n-heptane and cyclohexane.

Other very suitable almost completely water-immiscible aprotic solvents include aromatic and chlorinated hydrocarbons, e.g. benzene, toluene, o-, m- and p-xylene, trimethylbenzenes, dichloromethane, 1,2-dichloromethane, chloroform, monochlorobenzene and 1,2- and 1,3-dichlorobenzene. Very good results have been obtained with toluene and xylene.

The process of the present invention can be carried out starting from unsaturated or saturated aqueous solutions of water-soluble cyanide, in the latter case in the presence or absence of solid, water-soluble cyanide. For some solvents, it has been found that the presence of solid, water-soluble cyanide improves the yield and reaction time.

The use of alkanes or cycloalkanes and aqueous cyanide solutions without solid, water-soluble cyanide allows for a minimum reaction time. The use of aromatic or chlorinated hydrocarbons as well as aqueous cyanide solutions without solid, water-soluble cyanide slightly prolongs the reaction times, but sometimes this is recommended because the resulting reaction mixture can be used immediately in plant protection compositions without isolating the ester from the solvent. By using aromatic and chlorinated hydrocarbons as well as solid, water-soluble cyanide, reaction times are shortened. Solid, water-soluble cyanide can also be used in the presence of cycloalkanes.

Useful reaction times are achieved when the molar ratio of the amount of water to the total amount of water-soluble cyanide is greater than 0.05.

Other examples of suitable water-immiscible, aprotic solvents are dialkyl ethers and almost completely water-immiscible alkanols, e.g. diethyl ether, diisopropyl ether and diisobutyl ketone. Mixtures of solvents, e.g. alkanes and aromatic hydrocarbons, can be used. An example is heptane containing up to 10% by weight of benzene and / or toluene.

Preferably, group A of general formula II is phenoxy, since this substituent gives the most active form of pyrethroid plant protection products.

The group R of the general formula R-CO-Hal is alkyl optionally substituted by halogen-substituted phenyl, or a cycloalkyl group optionally substituted by one or more alkyl, alkenyl or haloalkenyl groups having up to 8 carbon atoms. The alkyl group may be straight or branched and preferably has up to ten carbon atoms. Preferably, the alkyl groups have a tertiary or quaternary carbon atom attached to the group -CO-Hal.

Examples of such alkanoyl halides are 2-methylpropanoyl chloride, 2,2-dimethylpropanoyl chloride and 2-methylbutanoyl bromide. Very good results have been obtained with 2-methyl-propanoyl chloride. Among the substituted alkyl groups R, mention may be made of the 1- (4-chlorophenyl) -2-methylpropyl group. The cycloalkyl group preferably contains 3 to 6 carbon atoms. Examples of cycloalkyl groups are cyclopropyl, cyclobutyl and cyclohexyl groups. Very good results have been obtained with optionally substituted cyclopropanecarbonyl halides, in particular 2,2,3,3-tetramethylcyclopropanecarbonyl halides and 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarbonyl halides. The latter halides 7 65989 may have a cis or trans structure or a mixture of these structures or a pure optical isomer or a mixture of optical isomers may be used.

The substituent shark of the general formula RC (O) hal is preferably a chlorine or bromine atom and especially a chlorine atom.

The process according to the invention can be carried out by slowly adding an acyl halide to a mixture of other starting materials. It is particularly preferred that the group R of the general formula RC (O) hal is 2,2,3,3-tetramethylcyclopropyl, 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropyl or 1- (4-chlorophenyl) -2-methylpropyl -liryhmä. Alternatively, all starting materials are reacted simultaneously with vigorous stirring of the reaction mixture.

The process is of particular interest when the aromatic aldehyde is 3-phenoxybenzaldehyde and the acyl halide is 2- (4-chlorophenyl) -3-methylbutanoyl chloride, 2,2,3,3-tetramethylcyclopropanecarbonyl chloride or 2- (2,2-dichlorovinyl) -3.3. - dimethylcyclopropanecarbonyl chloride, since the esters thus formed are cyano-3-phenoxybenzyl 2- (4-chlorophenyl) -3-methylbutanoate, o-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate and <-cyano-3 -phenoxybenzyl 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarboxylate, are particularly effective plant protection compounds.

The examples illustrate the invention. All experiments were performed at 23 ° C. The reaction mixture was stirred vigorously and the amount of ester formed was analyzed by gas chromatography. The reaction mixture was filtered to remove precipitated sodium chloride and solid sodium cyanide, if used, and the solutions were dried over anhydrous sodium sulfate. Evaporation of the solvent took place on a rotary evaporator at a pressure of 15 mm Hg. All yields are calculated from the aromatic aldehyde starting material.

Example 1 Preparation of o (cyano-3-phenoxybenzyl 2- (4-chlorophenyl) -3-methylbutanoate in the presence of n-heptane.

Equipped with a magnetic stirrer, 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2- (4-chlorophenyl) -3-methylbutanoyl chloride, 12 mmol of sodium cyanide, water, optionally a catalyst and 20 ml of n-heptane were added to a 50 ml round bottom flask and the resulting mixture was stirred. In this way, seven experiments were performed, cf. Table I.

8 65989

Table I

1 _2_3_4_5_6_ experimental Catalyst Added Reaction Ester No. -: -: - rr. . water time yield name Aldehyde ml h% amount mol% 11) - 1.0 3 86 18> 99 2 methyltri-2-heptylammonium 5 1.0 2 96 ium chloride 3 tetra-n-butylammonium chloride 2 1 .0 5 99 4 - "- 2 2,0 5 99 5 tetra-n-butylphosphonium bromide 2 1,0 3 99 6 n-hexadesyldimethylsulphonium iodide 2 1,0 3 97 7 1,4,7 , 10,13,16-hexaoxacyclooctadecane 2 1,0 3 94 1) is not according to the invention

Column 1 of Table I shows the number of experiments, column 2 the catalyst, column 4 the amount of water added to the starting mixture (excluding water containing sodium cyanide) and column 5 the reaction time. The yield of the desired ester is shown in column 6. Sodium cyanide was completely dissolved.

Example 2 Preparation of N-cyano-3-phenoxybenzyl 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarboxylate in the presence of n-heptane.

Equipped with a magnetic stirrer, 10 mmol of 3-phenoxybenzaldehyde, 2- (2,2-dichlorovinyl) -3,3-dimethylcyclopropanecarbonyl chloride, 12 mmol of sodium cyanide, water, optionally a catalyst and 20 ml of n-heptane were added to a 50 ml round bottom flask. The mixture thus formed was stirred. In this way, six experiments were performed, cf. Table II. Columns 3, 4 and 5 show the amounts of catalyst, water and acyl chloride added. The yields of the desired ester are shown in column 7.

9 65989

Table II

12 3 4 5 6 7 experimental Catalyst added acyl reaction ester No. -5-r-,, r · ... water chloride time h yield niml assy * __ 11) - - 1.0 10.2 3 49 21 94 44 99 2 methyl-2-methyl 5 1,0 10,2 1 96 style heptyl ammonium chloride 3 tetra-n-butyl ammonium chloride 2 1,0 10,5 1 90 4 99 4 Amberlite IRA 400 j (1 g) 1.0 10.5 5 95 5 Dobanol 91-63 2 1.0 10.0 2 80 6 1,4,7,10,13,16-hexaoxacyclo-2 1.0 10.0 2 76 octadecane 1) Not according to the invention 2) Trademark of a strongly basic anion exchange resin in which the polymer matrix is a styrene-divinylbenzene copolymer and the ionic group is a quaternary ammonium group. The chloride form was used.

3) Trademark of nonionic surfactant; it consists of a C8-C18 alcohol mixture and contains an average of six ethyleneoxy units. The alcohol mixture contains 85% n-alkanols and 15% 2-alkyl alkanols.

Example 3 Preparation of cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcyclopropanecarboxylate in the presence of n-heptane.

Methods A and B below were used to prepare this ester. This example shows that the slow addition of acid chloride to the reaction mixture over 0.5 to 2 hours clearly increases the yield at the end of this time.

.065989

Method A

To a 50 ml round bottom flask equipped with a magnetic stirrer were added 10 mmol of 3-phenoxybenzaldehyde, 10 nun of 2,2,3,3-tetramethylcyclopropanecarbonyl chloride, 12 mmol of sodium cyanide, 1.00 ml of water, optionally a catalyst and 20 ml of n-heptane. The molar ratio of water to sodium cyanide was 4.64 and no solid sodium cyanide was present. The amount of catalyst added was 0.20 mmol. The mixture thus formed was stirred for one and a half hours, then the mixture was analyzed.

Method B (slow addition of acid chloride)

To the flask of Method A was added 10 mmol of 3-phenoxybenzaldehyde, 12 mmol of sodium cyanide, 10 ml of n-heptane, 1.00 ml of water and optionally 0.20 mmol of catalyst. The molar ratio of water to sodium cyanide was 4.64. To the flask was added 10 mmol of 2,2,3,3-tetramethylcyclopropanecarbonyl chloride dissolved in 10 mL of n-heptane over 70-75 minutes. Ester yield was determined at the end of this time.

In this way, five experiments were performed. Table III shows the possible catalysts. The table also shows the yields of the desired ester.

Table III

Experiment Catalyst Ester Yield%

no catalyst Method A Method B

.jX) 17 40 2 1,4,7,10,13,16-Hexaoxacyclooctadecane 18 97 3 Tetra-n-butylammonium chloride 20 98 4 Methyltri-2-methylheptylammonium chloride 18 96 5 Dobanol 91 -6xx) 44 98 x) Not in accordance with the invention

xx) Explanation in Table II

The amount of catalysts used was 2 mol% in experiments 2-4 and 10 mol% in experiment 5, based on 3-phenoxybenzaldehyde.

In Experiment 4, Method B, the reaction mixture was filtered and the filtrate was washed twice with 20 ml of 1 M aqueous sodium bicarbonate solution and once with 20 ml of water. The washed filtrate was dried, the n-heptane was evaporated from the dried filtrate and the ester was obtained as a pale yellow oil, the oil was dissolved in 2.5 ml of methanol at 23 ° C, the resulting solution was cooled to -20 ° C and an ester precipitate was obtained. The ester was filtered and was greater than 98% pure.

Example 4 Preparation of x-cyano-3-phenoxybenzyl 2- (4-chlorophenyl) -3-methyl-butanoate on a larger scale.

Methods A (not according to the invention), B and C for the preparation of the desired ester were compared.

Method A (without phase transfer catalyst)

To a 500 mL round bottom flask equipped with a paddle stirrer was added 100 mmol of 3-phenoxybenzaldehyde, 100 mmol of 2- (4-chlorophenyl) -3-methylbutanoyl chloride, 120 mmol of sodium cyanide, 10 mL of water (which dissolved all sodium cyanide), and 200 mL of n-heptane. After stirring for 45 hours, the mixture was warmed to 40-50 ° C and filtered. The filtrate was washed twice with 50 ml of 1 M aqueous sodium bicarbonate solution and once with 50 ml of water, dried and the n-heptane was evaporated from the dried solution to give the desired ester, yield 99% and purity 96%.

Method B (in the presence of a onium compound) The experiment described in Part A of this example was repeated using 2 mol% of tetra-n-butylammonium chloride based on 3-phenoxybenzaldehyde. After 2 hours, the ester was obtained, yield 99% and purity 94%.

Method C (not in the presence of ionic surfactant) The experiment described in Part A of this example was repeated using 10 mol% "Dobanol 91-6" (described in Table II) based on 3-phenoxybenzaldehyde. After stirring for 3 hours, the reaction mixture was warmed to 40-50 ° C and filtered. To the filtrate was added 50 ml of ethanol (to break the emulsion formed), the filtrate was washed twice with 50 ml of 1 M aqueous sodium bicarbonate solution and once with 50 ml of water, dried and the n-heptane was evaporated from the dried solution to give an ester, yield 98% and purity 97%.

The above results are summarized in the following Table IV

12 65989

Table IV

test Catalyst n: ° name Aldehyde Reaction Ester Ester amount mole% time h yield purity%% 1 no catalyst - 45 99 96 2 tetra-n-butyl 2 2 99 94 ammonium chloride 3 Dobanol 91-61) 10 3 98 97 1) Explanation in Table II.

Example 5 Es-cyano-3-phenoxybenzyl 2- (4-chlorophenyl) -3-methylbutanoate in the presence of solid cyanide.

To a 50 mL round bottom flask equipped with a magnetic stirrer were added 10 mmol of 3-phenoxybenzaldehyde, 10.5 mmol of 2- (4-chlorophenyl) -3-methylbutanoyl chloride, 12 mmol of sodium cyanide, 20 mL of toluene, phase transfer catalyst and water. The mixture thus formed was stirred for various times, and the mixture was analyzed. In this way, six experiments were performed. The results are shown in Table V, which shows the catalysts and the amounts of water added, if any. The amount of catalyst used was 0.20 mmol.

Table V

1 2 3 4 5 6 experiment catalyst added water and reaction ester No water NaCNt time yield ml molar ratio h% 1 1,4,7,10,13,16-hexaoxacyclo- 0,012 2 60 octadecane 20 91 80 97 2 - "- 0.02 0.105 3 100 3 -" - 1.00x) 4.64 2 95 4 98 20 100 4 tetra-n-butylammonium bromide 0.012 2 30 22 32 5 - "- 0.02 0.105 2 81 18 98 6 - "- 1.00X) 4.64 2 71 22 81 x) For comparison, no solid cyanide was used in the two experiments.

13 65989 The sodium cyanide used had a maximum particle size of 0.5 mm and contained 0.44% by weight of water. The molar ratio of water to sodium cyanide was calculated taking into account the amount of water in the sodium cyanide and any water added. By way of comparison, the molar ratio of water to sodium cyanide in a saturated aqueous solution of sodium cyanide at 23 ° C is 4.1.

Claims (6)

14 65989 A process for preparing an O <-cyanobenzyl carboxylate ester having the general formula CM s -R 4 CO.O-CH 2 R 2 = / wherein R is an alkyl group optionally substituted by a halogen-substituted phenyl group or a cycloalkyl group optionally substituted one or more alkyl, alkenyl or haloalkenyl groups having up to 8 carbon atoms, and A is phenoxy, phenylthio or benzyl, by reacting a Bent-residual hydride of the formula OCH ---- ζ III with the formula R-CO-Hal ( wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide and a substantially water-immiscible aprotic solvent, characterized in that the reaction is carried out in the presence of a phase transfer catalyst. 2 I 4 r -x-r4 y R3 1 2 3.4 wherein X is a nitrogen, phosphorus or arsenic atom, R, R, R and R are alkyl, aralkyl, alkylaryl or aryl groups and Y is a monovalent ion, or a sulfonium compound , having the general formula 15 65989 ~ R6 Π * i 5 7 R -SR Y 5 6 7 wherein R, R and R are alkyl groups and Y is a monovalent ion. Process according to Claim 1, characterized in that the phase transfer catalyst is an onium compound, a macrocyclic polyether or a surfactant. Process according to Claim 2, characterized in that the onium compound is a quaternary onium compound of the general formula r1 ~ | + Process according to Claim 2, characterized in that the phase transfer catalyst is a surfactant which is a poly (alkyleneoxy) derivative formed by the reaction of an alkanol having 8 to 20 carbon atoms with ethylene oxide or propylene oxide. Process according to one of the preceding claims, characterized in that the molar ratio of the phase transfer catalyst to the benzaldehyde of the general formula III is 1: 5 to 1: 500. Process according to one of the preceding claims, characterized in that the reaction is carried out in the presence of a phase transfer catalyst at a temperature of 10 to 50 ° C. 65989 16