CA1122224A - Preparation of pesticidal benzyl esters - Google Patents
Preparation of pesticidal benzyl estersInfo
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- CA1122224A CA1122224A CA000271451A CA271451A CA1122224A CA 1122224 A CA1122224 A CA 1122224A CA 000271451 A CA000271451 A CA 000271451A CA 271451 A CA271451 A CA 271451A CA 1122224 A CA1122224 A CA 1122224A
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- general formula
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- amount
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/14—Preparation of carboxylic acid nitriles by reaction of cyanides with halogen-containing compounds with replacement of halogen atoms by cyano groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C323/00—Thiols, sulfides, hydropolysulfides or polysulfides substituted by halogen, oxygen or nitrogen atoms, or by sulfur atoms not being part of thio groups
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- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Toxicology (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
A B S T R A C T
Process for the preparation of an ester of the general formula:- II
wherein R is an optionally substituted alkyl or cycloalkyl group and A is phenoxy, phenylthio or benzyl, which comprises reacting a benzaldehyde of the formula:- III
with an acyl halide of the formula R.CO.Hal (wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide, a substantially water-immiscible aprotic solvent and a phase transfer catalyst.
Process for the preparation of an ester of the general formula:- II
wherein R is an optionally substituted alkyl or cycloalkyl group and A is phenoxy, phenylthio or benzyl, which comprises reacting a benzaldehyde of the formula:- III
with an acyl halide of the formula R.CO.Hal (wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide, a substantially water-immiscible aprotic solvent and a phase transfer catalyst.
Description
~12Z224 This invention relates to a process for the preparatio~ of certain insecticidally-active esters of the so-called "synthetic pyrethroid" type.
It is known, according to D.A.S. 2,231,312, that some synthetic pyrethroids may be prepared by the reaction of a s~bst~tuted cyclopropanecarbonyl halide with a 3-substituted benzaldehyde in the presence of aqueous sodium or potassium cyanide. Such a p~ocess yields pyrethroids of the following type:-/ \ CN
/ ~ COObH ~
The Applicant has found that yields of the ester of the type depicted in formula I as well as other esters falling within the "synthetic pyrethroid" field ~y be prepared more efficiently and with higher yields by the use of a particular catalyst.
Accordingly, the present invention provides a process for the preparation of an ester of general formula:-A
B.CO.O - CB ~ II
wherein R is an optionally-substituted alkyl or cycloalkyl group and A is phenoxy, phenylthio or benzyl, which comprises reacting li22~24 a benzaldehyde ~f the formula:-A
OCH ~ III
with an acyl halide of the formula R.CO.Hal (wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide, a substantially water-immiscible aprotic ~olvent and a phase transfer catalyst.
The phase transfer catalyst may be any reagent which is capab~ of accelerating interphase reactions in aqueous/
organic two-phase systems.
The phase transfer catalyst may be an onium compound, particularly a ~uaternary onium compound of the general formula Rl +
R2_x_R4 Y
wherein X represents a nitrogen, phocphorus or arsenic atom, Rl, R2, R3 and R4 each an al~yl, aralkyl, alkaryl or aryl group and Y a monovalent ion, e.g. a halide such as chloride, bromi~e or iodide, or an alkylsulphate such a~ methylsulphate or ethylsulphate or a ~ulphonium compound of the general formula r R6 1 +
L R5-S_R7 ~ y_ wherein R5, R6 and R7 each represent an alkyl group and Y a monovalent ion, e.g. a halide such as chloride, bromide ~22Z24 or iodide, or an alkylsulphate such as methylsulphate or ethylsulphate. Preferably the alkyl groups contain l to 18 carbon atoms and the aralkyl and alkaryl groups contain up to lO carbon atoms; the aryl group is preferably phenyl.
Examples of suitable onium compounds are tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, methyltri-2-methylphenyl-ammonium chloride, tetramethyl-phosphonium iodide, tetra-n-butylphosphonium bromide, methyltriphenylarsonium iodide, ethyl-2-methylpentadecyl-
It is known, according to D.A.S. 2,231,312, that some synthetic pyrethroids may be prepared by the reaction of a s~bst~tuted cyclopropanecarbonyl halide with a 3-substituted benzaldehyde in the presence of aqueous sodium or potassium cyanide. Such a p~ocess yields pyrethroids of the following type:-/ \ CN
/ ~ COObH ~
The Applicant has found that yields of the ester of the type depicted in formula I as well as other esters falling within the "synthetic pyrethroid" field ~y be prepared more efficiently and with higher yields by the use of a particular catalyst.
Accordingly, the present invention provides a process for the preparation of an ester of general formula:-A
B.CO.O - CB ~ II
wherein R is an optionally-substituted alkyl or cycloalkyl group and A is phenoxy, phenylthio or benzyl, which comprises reacting li22~24 a benzaldehyde ~f the formula:-A
OCH ~ III
with an acyl halide of the formula R.CO.Hal (wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide, a substantially water-immiscible aprotic ~olvent and a phase transfer catalyst.
The phase transfer catalyst may be any reagent which is capab~ of accelerating interphase reactions in aqueous/
organic two-phase systems.
The phase transfer catalyst may be an onium compound, particularly a ~uaternary onium compound of the general formula Rl +
R2_x_R4 Y
wherein X represents a nitrogen, phocphorus or arsenic atom, Rl, R2, R3 and R4 each an al~yl, aralkyl, alkaryl or aryl group and Y a monovalent ion, e.g. a halide such as chloride, bromi~e or iodide, or an alkylsulphate such a~ methylsulphate or ethylsulphate or a ~ulphonium compound of the general formula r R6 1 +
L R5-S_R7 ~ y_ wherein R5, R6 and R7 each represent an alkyl group and Y a monovalent ion, e.g. a halide such as chloride, bromide ~22Z24 or iodide, or an alkylsulphate such as methylsulphate or ethylsulphate. Preferably the alkyl groups contain l to 18 carbon atoms and the aralkyl and alkaryl groups contain up to lO carbon atoms; the aryl group is preferably phenyl.
Examples of suitable onium compounds are tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, methyltri-2-methylphenyl-ammonium chloride, tetramethyl-phosphonium iodide, tetra-n-butylphosphonium bromide, methyltriphenylarsonium iodide, ethyl-2-methylpentadecyl-
2-methyl~ndecylsulphonium ethylsulphate, methyldinonyl-sulphonium methylsulphate and n-hexadecyldimethylsulphonium iodide. Very good results have been obtained with quaternary ammonium compound~.
The onium compound may be a hydroxide or a salt and can be employed as the functional portion of a strongly-basic anion exchange resin having a structural portion (polymer matrix) and a functional portion (ion-active group).
Of special importance are ~olystyrene resins, such as copolymers o~ aromatic monovinyl compounds and aromatic polyvinyl compounds, particularly styrene/divinylbenzene copolymers. The fun~tional portion is a quaternary ammonium, phosphonium or arsonium group. Examples of strongly-basic anion exchange resins which may be employed are those derived from trimethylamine (such as the products known under the trade names of "Amberlite IRA-400", "Amberlite IRA-401", 'Amberlite IRA-402", "Amberlite IRA-900", "Duolite A-lOl-D", "Duolite ES-lll", "Dowex l", Dowex ll", "Dowex 21K" and "Ionac A-450"), and those derived frorr dimethylethanol-amine (such as the products 3cnown under the trade names of "Amberlite IRA-4lO", "Amberlite IRA-9ll", "Dowex 2", "Duolite A-102-D", "Ionac A-542" and "Ionac A-550").
iiZ2224 Very good results have been obtained with those derived from tr-methylamine.
Other suitable phase transfer catalysts are macrocyclic polyethers known as "cro~n ethers". These compounds, together with their preparation, are described in the literature, for example in Tetrahedron Letters No.
18(1972) pp. 1793-1796, and are commonly designated by reference to the total number of atoms forming the macro-cyclic ring together with the number of oxygen atoms in that ring. Thus the macrocyclic polyether whose formal chemical name is 1,4,7,10,13,16-hexaoxacyclooctadecane is designated as "18-crown-6". Other examples of suitable macrocyclic polyethers are 3,4-benzo-1,6,9,12,15,18,21-heptaoxacyclotricos-3ene and 3,4-benzo-1,6,~,12,-tetra-oxacyclotetradec-3-ene. 18-Crown-6 is particularly suit~ble.
Other suitable phase transfer catalysts are surface-active agents. A "~urface-active agent" is defined as in Kirk-Othmer, "Encyclopedia of Chemical Technology", second edition, volume 19(1969), page 508: "An organic compound that encompasses in the same molecule two dissimilar structural groups, one being water-soluble and one being water-insoluble".
The surface-active agent is preferably non-ionic, such as a poly(alkyleneoxy) derivative formed by reacting a higher alcohol, alkylphenol or ~atty acid with ethylene oxide or propylene oxide. Suitable alcohols, alkylphenols or fatty acids contain an alky' group of 8-20 carbon atoms and the number Or alkyleneoxy units is in the range of 1-50. A particularly suitable non-ionic surface-active agent (referred to in the examples as "Dobanol 91-6") is formed from a Cg-Cll n-alkanol mixture and contains an average of six ethyleneoxy units. The non-ionic surface-active agent may be an alkylbenzene containing a straight alkyl group. Suitable alkylbenzenes contain an alkyl group of 8-20 carbon atoms.
The molar ~atio of the amount of phase transfer catalyst to the amount of benzaldehyde of the general formula III may vary within wide limits, but~ is suitably from 1:5 to 1:500. The use of low molar ratios will require a longer time to complete th~ reaction, whilst the u~e of higher molar ratios naturally increases the cost to produce a given quantity of eæter. Thus, the choice of reaction time and molar ratio catalyst to benzaldehyde are mutually interdependent, and in any individual instance will depend on the local economic factors. Very good results are usually obtained at molar ratios from 1:10 to 1:100.
Another advantage of the process according to the present invention is that the molar ratio of the amount of acyl halide (R.CO.Hal) to the amount of benzaldehyde is 1:1 or slightly in excess thereof. This molar ratio is preferably in the range of from 1,1:1.0 to 1,0:1Ø
The mQlar ratio of the amount of water-soluble cyanide to the amount of aromatic aldehyde is suitably from 1~2~224 1.5:1 to 1.0:1.0 and preferably from 1.3:1 to 1.02:1.00.
By "water-soluble cyanide" is meant a water-soluble salt of hydrogen cyanide, Of the water-sc,luble cyanides alkali-metal cyanides and alkaline-earth-metal cyanides are preferred. Sodium cyanide is particularly preferred, because it affords the esters of the general formula II in the shortest reaction time.
The temperature at which the process is conducted is suitably above 0C and is preferably in the range 10C
1~ to 50C. Very good results have been obtained at temperatures in the range 15 C to 40C. The process has the advantage that ambient tempera~ures are very suitable.
Examples of suitable substantially water-immiscible aprotic solvents are alkanes or cycloalkanes or a mixture thereof; particular examples being n-hexane, n-heptane, n-octane, n-nonane, n-decane and their isomers (for example 2-methylpentane, 3-methylpentane, 2-methylhexane, 3-methyl-hexane and 2,4,4-trimethylpentane) and cyclohexane and methylcyclohexane. Gasolines rich in alkanes are also very suitable, for example with a boiling range at atmospheric pressure between 40 and 65C, 60 and 80C or 80 and 110C.
Very good results have been obtained with n-heptane and cyclo-hexane.
Other very suitable substantially water-immiscible aprotic solvents are aromatic hydrocarbons and chlorinated hydrocarbons, for example benzene, toluene, o-, m- and ~122224 ~-xylene, the trimethylbenzenes, dichloromethane, 1,2-di-chloromethane, chloroform, monochlorobenzene and 1,2-and 1,3-dichlorobenzene, Very good results have been obtained with toluene and xylene.
The process according to the present invention may be conducted start.ing from unsaturated or saturated aqueous solutions of water-soluble cyanide and, in the latter case n the presence or absence o~ solid water-soluble cyanide.
~ith some solvents it has been found that the pres~nce of solid water-soluble cyanide improves the yield and reaction time.
The use of alkanes or cycloalkanes in combination with aqueous solutions of cyanide in the absence of solid water-soluble cyanide enables the reaction time to be kept to a minimum. The use of aromatic hydro-carbons or chlorinated hydrocarbons in combination with aqueous solutions of cyanide in the absence of solid water-soluble cyanide produces slightly longer reaction times but nevertheless is sometimes pre~erred becau~e the resulting reaction mixture can be used directly for pesticidal formulations without further separation of the ester from the solvent. The use of aromatic hydrocarbons and chlorinated hydrocarbons in combination with solid water-soluble cyanide.
2~ produces short reaction times. Solid water-soluble 112~224 g cyanide may however also be used in the presence of (cyclo)alkanes.
Useful reaction times can be obtained when molar ratios of the amount of water to the total amount of water-soluble cyanide is higher than 0.05.
Other examples Gf substantially water-immiscible aprotic solvents are dialkyl ethers and substantially water-immiscible alkanones, for example di~thyl ether, diisopropyl ether and diisobutyl ketone. Mixtures of solvents, for example of alkanes and aromatic hydrocarbons may be employed for example of n-heptane containing up to 10% by weight of benzene and/or toluene.
The group A in the general formula II is preferably phenoxy because this substituent gives rise to the most active form of the pyrethroid pesticides.
The group R in the general formula RC(O)Hal is defined as an optionally-substituted alkyl or cycloalkyl ~roup. The alkyl group may be straight or branched and preferably contains up to 10 carbon atoms. The alkyl groups preferably have a tertiary or quaternary carbon atom bound to the group -C(O)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. The alkyl group may carry as substituents, for example, hydrocarbyloxy or substituted phenyl groups, e.g. a halophenyl group. Very good results have been obtained with 1-(4-chlorophenyl)-2-methylpropyl groups. The cycloalkyl group itself preferably contains 3 to ~ carbon atoms and has as optiona~- ~ubstituents a group or groups selected from alkyl, alkenyl, haloalkenyl each of which suitably contains up to 8 carbon atoms. Examples of cycloalkyl groups are cyclopropyl, cyclobutyl and cyclohexyl groups. Very good results have been obtained with optionally substituted cyclopropanecarbonyl halides, particularly with 2,2,3,3-tetramethylcyclo-propanecarbonyl halides and 2-(2,2-dichlorovinyl)-3,3-di-10 methylcyclopropanecarbonyl halides. The latter halides may have a cis or trans structure or may be a mixture of such structures and may be a pure optical isomer or a mixture of optical isomers.
The substituent Hal in the general formula RC(O)Hal 15 is preferably a chlorine or bromine atom and in particular a chlorine atom;
The process according to the invention may be carried out by gradual addition of the acyl halide to a mixture, preferably a stirred mixture, of the other starting compounds 20 (particularly advan~geous when R in the general formula RC(O)Hal represents a 2,2,3,3-tetramethylcyclop~opyl group a 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropyl group, or a 1-(4-chlorophenyl)-2-methylpropyl group. Alternati~ely the to~al amounts of the starting materials may be placed 25 together and the reaction allowed to take place 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-tetra-methylcyclopropanecarbonyl chloride or 2-(2,2-dichloro-vinyl)-3,3-dimethylcyclopropanecarbonyl chloride, because the esters then formed, a-cyano-3-phenoxybenzyl 2-(4-chloro-phenyl)-3-methy_butanoate, ~-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcycloprbpanecarboxylate and -cyano-3-phenoxy-benzyl 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarboxy-late, respectively, are especially active pesticidal compounds.
The Exam~les further illustrate the invention. All experiments were conducted at a temperature of 23C The reaction mixtures were stirred vigorously and analysed by gas-liquid chromatography to determine the yield of the ester formed. Reaction mixtures were filtered to remove pre-cipitated sodium chloride and solid sodium cyanide, if any, and drying of solutions was carried out over anhydrous sodium sulphate. Flaæhing of the solvent took place in a eilm evaporator at a pressure of 15 mm Hg. All yields are calcu-lated on starting aromatic aldehyde~
EXAMPLE I
Pre~aration of ~-cyano-3-~henox~benz~l 2-(4-chloro~hen~
___ ______________ ____ _ _____ ____ ____ ________ ___ _ _ __ meth~abutanoate in the ~resence of n-he~tane ~122~24 A 50 ml round-bottomed flask equippe~ with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl chloride, 12 mmol o~ sodium cyanide, water, a cataiyst, if any, and 20 ml of n-heptane and the mixture thus formed was stirred. Seven experi-ments were carried Out in this manner, see Table I.
Table I
1 2 ~ 4 ~ 6 Exp. __ CataI~st Water Reaction time, Yield of ester, no. ~ame ~mount added h %
%mol on ml ____ ______________ aadeh~d_ ____ ) _ _ 1.0 3 86 18 more than 99 2 methyl-tri-2- 5 1.0 2 96 methyl-heptyl-ammonium chloride
The onium compound may be a hydroxide or a salt and can be employed as the functional portion of a strongly-basic anion exchange resin having a structural portion (polymer matrix) and a functional portion (ion-active group).
Of special importance are ~olystyrene resins, such as copolymers o~ aromatic monovinyl compounds and aromatic polyvinyl compounds, particularly styrene/divinylbenzene copolymers. The fun~tional portion is a quaternary ammonium, phosphonium or arsonium group. Examples of strongly-basic anion exchange resins which may be employed are those derived from trimethylamine (such as the products known under the trade names of "Amberlite IRA-400", "Amberlite IRA-401", 'Amberlite IRA-402", "Amberlite IRA-900", "Duolite A-lOl-D", "Duolite ES-lll", "Dowex l", Dowex ll", "Dowex 21K" and "Ionac A-450"), and those derived frorr dimethylethanol-amine (such as the products 3cnown under the trade names of "Amberlite IRA-4lO", "Amberlite IRA-9ll", "Dowex 2", "Duolite A-102-D", "Ionac A-542" and "Ionac A-550").
iiZ2224 Very good results have been obtained with those derived from tr-methylamine.
Other suitable phase transfer catalysts are macrocyclic polyethers known as "cro~n ethers". These compounds, together with their preparation, are described in the literature, for example in Tetrahedron Letters No.
18(1972) pp. 1793-1796, and are commonly designated by reference to the total number of atoms forming the macro-cyclic ring together with the number of oxygen atoms in that ring. Thus the macrocyclic polyether whose formal chemical name is 1,4,7,10,13,16-hexaoxacyclooctadecane is designated as "18-crown-6". Other examples of suitable macrocyclic polyethers are 3,4-benzo-1,6,9,12,15,18,21-heptaoxacyclotricos-3ene and 3,4-benzo-1,6,~,12,-tetra-oxacyclotetradec-3-ene. 18-Crown-6 is particularly suit~ble.
Other suitable phase transfer catalysts are surface-active agents. A "~urface-active agent" is defined as in Kirk-Othmer, "Encyclopedia of Chemical Technology", second edition, volume 19(1969), page 508: "An organic compound that encompasses in the same molecule two dissimilar structural groups, one being water-soluble and one being water-insoluble".
The surface-active agent is preferably non-ionic, such as a poly(alkyleneoxy) derivative formed by reacting a higher alcohol, alkylphenol or ~atty acid with ethylene oxide or propylene oxide. Suitable alcohols, alkylphenols or fatty acids contain an alky' group of 8-20 carbon atoms and the number Or alkyleneoxy units is in the range of 1-50. A particularly suitable non-ionic surface-active agent (referred to in the examples as "Dobanol 91-6") is formed from a Cg-Cll n-alkanol mixture and contains an average of six ethyleneoxy units. The non-ionic surface-active agent may be an alkylbenzene containing a straight alkyl group. Suitable alkylbenzenes contain an alkyl group of 8-20 carbon atoms.
The molar ~atio of the amount of phase transfer catalyst to the amount of benzaldehyde of the general formula III may vary within wide limits, but~ is suitably from 1:5 to 1:500. The use of low molar ratios will require a longer time to complete th~ reaction, whilst the u~e of higher molar ratios naturally increases the cost to produce a given quantity of eæter. Thus, the choice of reaction time and molar ratio catalyst to benzaldehyde are mutually interdependent, and in any individual instance will depend on the local economic factors. Very good results are usually obtained at molar ratios from 1:10 to 1:100.
Another advantage of the process according to the present invention is that the molar ratio of the amount of acyl halide (R.CO.Hal) to the amount of benzaldehyde is 1:1 or slightly in excess thereof. This molar ratio is preferably in the range of from 1,1:1.0 to 1,0:1Ø
The mQlar ratio of the amount of water-soluble cyanide to the amount of aromatic aldehyde is suitably from 1~2~224 1.5:1 to 1.0:1.0 and preferably from 1.3:1 to 1.02:1.00.
By "water-soluble cyanide" is meant a water-soluble salt of hydrogen cyanide, Of the water-sc,luble cyanides alkali-metal cyanides and alkaline-earth-metal cyanides are preferred. Sodium cyanide is particularly preferred, because it affords the esters of the general formula II in the shortest reaction time.
The temperature at which the process is conducted is suitably above 0C and is preferably in the range 10C
1~ to 50C. Very good results have been obtained at temperatures in the range 15 C to 40C. The process has the advantage that ambient tempera~ures are very suitable.
Examples of suitable substantially water-immiscible aprotic solvents are alkanes or cycloalkanes or a mixture thereof; particular examples being n-hexane, n-heptane, n-octane, n-nonane, n-decane and their isomers (for example 2-methylpentane, 3-methylpentane, 2-methylhexane, 3-methyl-hexane and 2,4,4-trimethylpentane) and cyclohexane and methylcyclohexane. Gasolines rich in alkanes are also very suitable, for example with a boiling range at atmospheric pressure between 40 and 65C, 60 and 80C or 80 and 110C.
Very good results have been obtained with n-heptane and cyclo-hexane.
Other very suitable substantially water-immiscible aprotic solvents are aromatic hydrocarbons and chlorinated hydrocarbons, for example benzene, toluene, o-, m- and ~122224 ~-xylene, the trimethylbenzenes, dichloromethane, 1,2-di-chloromethane, chloroform, monochlorobenzene and 1,2-and 1,3-dichlorobenzene, Very good results have been obtained with toluene and xylene.
The process according to the present invention may be conducted start.ing from unsaturated or saturated aqueous solutions of water-soluble cyanide and, in the latter case n the presence or absence o~ solid water-soluble cyanide.
~ith some solvents it has been found that the pres~nce of solid water-soluble cyanide improves the yield and reaction time.
The use of alkanes or cycloalkanes in combination with aqueous solutions of cyanide in the absence of solid water-soluble cyanide enables the reaction time to be kept to a minimum. The use of aromatic hydro-carbons or chlorinated hydrocarbons in combination with aqueous solutions of cyanide in the absence of solid water-soluble cyanide produces slightly longer reaction times but nevertheless is sometimes pre~erred becau~e the resulting reaction mixture can be used directly for pesticidal formulations without further separation of the ester from the solvent. The use of aromatic hydrocarbons and chlorinated hydrocarbons in combination with solid water-soluble cyanide.
2~ produces short reaction times. Solid water-soluble 112~224 g cyanide may however also be used in the presence of (cyclo)alkanes.
Useful reaction times can be obtained when molar ratios of the amount of water to the total amount of water-soluble cyanide is higher than 0.05.
Other examples Gf substantially water-immiscible aprotic solvents are dialkyl ethers and substantially water-immiscible alkanones, for example di~thyl ether, diisopropyl ether and diisobutyl ketone. Mixtures of solvents, for example of alkanes and aromatic hydrocarbons may be employed for example of n-heptane containing up to 10% by weight of benzene and/or toluene.
The group A in the general formula II is preferably phenoxy because this substituent gives rise to the most active form of the pyrethroid pesticides.
The group R in the general formula RC(O)Hal is defined as an optionally-substituted alkyl or cycloalkyl ~roup. The alkyl group may be straight or branched and preferably contains up to 10 carbon atoms. The alkyl groups preferably have a tertiary or quaternary carbon atom bound to the group -C(O)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. The alkyl group may carry as substituents, for example, hydrocarbyloxy or substituted phenyl groups, e.g. a halophenyl group. Very good results have been obtained with 1-(4-chlorophenyl)-2-methylpropyl groups. The cycloalkyl group itself preferably contains 3 to ~ carbon atoms and has as optiona~- ~ubstituents a group or groups selected from alkyl, alkenyl, haloalkenyl each of which suitably contains up to 8 carbon atoms. Examples of cycloalkyl groups are cyclopropyl, cyclobutyl and cyclohexyl groups. Very good results have been obtained with optionally substituted cyclopropanecarbonyl halides, particularly with 2,2,3,3-tetramethylcyclo-propanecarbonyl halides and 2-(2,2-dichlorovinyl)-3,3-di-10 methylcyclopropanecarbonyl halides. The latter halides may have a cis or trans structure or may be a mixture of such structures and may be a pure optical isomer or a mixture of optical isomers.
The substituent Hal in the general formula RC(O)Hal 15 is preferably a chlorine or bromine atom and in particular a chlorine atom;
The process according to the invention may be carried out by gradual addition of the acyl halide to a mixture, preferably a stirred mixture, of the other starting compounds 20 (particularly advan~geous when R in the general formula RC(O)Hal represents a 2,2,3,3-tetramethylcyclop~opyl group a 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropyl group, or a 1-(4-chlorophenyl)-2-methylpropyl group. Alternati~ely the to~al amounts of the starting materials may be placed 25 together and the reaction allowed to take place 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-tetra-methylcyclopropanecarbonyl chloride or 2-(2,2-dichloro-vinyl)-3,3-dimethylcyclopropanecarbonyl chloride, because the esters then formed, a-cyano-3-phenoxybenzyl 2-(4-chloro-phenyl)-3-methy_butanoate, ~-cyano-3-phenoxybenzyl 2,2,3,3-tetramethylcycloprbpanecarboxylate and -cyano-3-phenoxy-benzyl 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecarboxy-late, respectively, are especially active pesticidal compounds.
The Exam~les further illustrate the invention. All experiments were conducted at a temperature of 23C The reaction mixtures were stirred vigorously and analysed by gas-liquid chromatography to determine the yield of the ester formed. Reaction mixtures were filtered to remove pre-cipitated sodium chloride and solid sodium cyanide, if any, and drying of solutions was carried out over anhydrous sodium sulphate. Flaæhing of the solvent took place in a eilm evaporator at a pressure of 15 mm Hg. All yields are calcu-lated on starting aromatic aldehyde~
EXAMPLE I
Pre~aration of ~-cyano-3-~henox~benz~l 2-(4-chloro~hen~
___ ______________ ____ _ _____ ____ ____ ________ ___ _ _ __ meth~abutanoate in the ~resence of n-he~tane ~122~24 A 50 ml round-bottomed flask equippe~ with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl chloride, 12 mmol o~ sodium cyanide, water, a cataiyst, if any, and 20 ml of n-heptane and the mixture thus formed was stirred. Seven experi-ments were carried Out in this manner, see Table I.
Table I
1 2 ~ 4 ~ 6 Exp. __ CataI~st Water Reaction time, Yield of ester, no. ~ame ~mount added h %
%mol on ml ____ ______________ aadeh~d_ ____ ) _ _ 1.0 3 86 18 more than 99 2 methyl-tri-2- 5 1.0 2 96 methyl-heptyl-ammonium chloride
3 tetra-n-butylsmmo- 2 1.0 5 99 niumch~oride
4 ditto 2 2.0 5 99 tetra-n-butyl- 2 1.0 3 99 phosphonium bromide 6 n-hexadecyld~ethyl 2 1.0 3 97 cUlp~nium iodide 7 1,4,7,10,13,16- 2 1.0 3 94 hexaoxacyclooctadecane _________________________________________________________________ 1) not according to the invention.
Column 1 in Table I states the number of the experiment, column 2 the catalyst, column 4 the amount of water added to the starting mixture (excluding the water present in the sodium cyanide) and column 5 the reaction time. The yield of the 1~2~:~24 ~esired ester is presented in column 6. The sodium cyanide was completely dissolved.
EXAMPLE II
Pre~ara_ic,n_of__c~ano-~-~henox~benz~l 2-(2l2-dichloro-v_n~ -dimeth~ac~cao~ro~anecarbox~la e_in the_~re_en_e of n-he~tane __ _____ ___ _ A 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, an amount of 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecar-bonyl chloride, 12 mmol of sodium cyanide, water, a catalyst, if any and 20 mi of n-heptane The mixture thus formed was stirred. Six experiments were carried out in this manner, see Table II. Column 3,4 and 5 state the amounts of cata-lyst~ water and acyl chloride added. The yield of the desired ester is presented in column 7.
~12Z224 Table II
_______________________________________________________________ E Catalyst Water Acyl Reaction Yield of P -------_____-_ ----- added chloride, time, ester, %
no. name ~mount ml mmol h %mol on ___ ___________ _aad_h~de ____ ________ _______ _________ 1) 1 - - 1.0 10.2 3 49 2 methyl-tri-2 5 1.0 10.2 1 96 m~thyl~eptyl-ammonium chloride 3 tet~a-n-butyl- 2 1.0 10.5 1 90 Ammonium chloride 4 Amb2e~1ite IRA '(1 gram)l.0 10,5 5 95 Dobanol 91-63) 2 1.0 10.0 2 80 6 1,4,7,10,13,16- 2 1.0 10.0 2 76 ~5 hexaoxacycloocta-decane ____________________ ________________________________________ 1) not according to the invention 2) a trade mark for a strongly basic anion exchange resin having a styrene/divinylbenzene copolymer as polymer matrix and a quaternary ammonium group as ion-active group.
The chloride form was used.
3) a trade mark for a non-ionic surface-active agent formed from a C9-Cll alcohol mixture and containing an a~erage of 6 ethyleneoxy units, the alcohol mixture consists oP 85%
n-alkanols and 15g 2-alkylalkanols.
EXAMPLE III
Pre~arat_on_Qf -c~ano-3-~henox~benz~l 2~2~3-tetrameth~l-c~vclopro~anecarbox~late in the ~resence of n-he~tane.
___ __ _________ ____________ _______________ ____ Methods A and B as indicated below were employed to prepare this ester. This example demonstrates that a gradual addition of the acid chloride to the reaction mixture during a period of 0.5 t~ 2 hours produces marked increases in yield at the end of that period.
Method A
A 50 ml round-bottomed flask equipped with a magneti~
stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2,2,3,3-tetramethylcyclopropanecarbonyl chloride, 12 mmol of sodium cyanide, 1.00 ml of uater, a catalyst, if any, and 20 ml of n-heptane. The molar ratio of water to NaCN
was 4.64, solid NaCN being absent. The catalyst was added in an amount of 0.20 m~ol. The nixture thus formed was stirred for 1.5 hours and analysed.
Method B (gradual addition of acid chloride) The flask use~ for method A was charged with 10 mmol of 3-phenoxybenzaldehyde, 12 mmol of sodium cyanide, 10 ml of n-heptane, 1.00 ml of water and 0.20 m~ol of a catalyst, if any, the molar ratio of water to NaCN being 4.64.
An amount of 10 mmol of 2,2,3,3-tetramethylcyclopropane-carbonyl chloride dissolved in 10 ml of n-heptane was introduced into the flask during a period of 70-75 min.
The yield of the ester was determined at the end of this period.
112Z;~2~
Five experiments were carried out in this manner.
Table III states the catalysts u,ed, if any. This Table al~o presents the yield of the desired ester.
Table III
Exp. Catalyst Yield of ester, %
no. Method A Method B
______________________________ ________ _________ l*) none 17 40 21,4,7,10,13,16-hexaoxa- 18 97 cyclooctadecane 3 tetra-n-butylammonium chloride 20 98 4 methyl-t~i-2-methylheptyl- 18 96 ammonium chloride Dobanol 91-6 ) 44 98 ______________________________________________________ not according to the invention ) for explanation of this word, see Table II.
The amounts of the catalysts used were 2%m in the experiments 2-4 and 10 %m in experiment 5, calculated on 3-phenoxybenzaldehyde.
The reaction mixture obtained in experiment 4, method B, was filtered and the filtrate washed twice with 20 ml of a 1 M aqueous solution of sodium bicarbonate and once with 20 ml of water. The washed filtrate was dried and the n-hep-tane was flashed from the dried filtrate to obtain the ester as a pale yellow oil. This oil was dissolved in 2.5 ml of methanol at 23 C and the solution obtained was cooled to a temperature of ~0C to give a precipitate of the ester. The ester was filtered and had a purity of more than 98%.
EXAMPLE IV
Pre~aration of ~-c2ano-3-~henoxybenzyl 2-~4-chloro~hen~1)-3-meth~lbutanoate on an enlarged s_aae Methods A (not according to the invention), B and C were compared for the preparation of the desiréd ester.
Method Al in the absence of a phase transfer catalyst.
A 500 ml round-bottomed flask equipped with a paddle stirrer was charged with 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 a temperature between 40 and 50C
and filtered. The filtrate was washed twice with 50 ml of a 1 M aqueous sodium bicarbonate solution, once with 50 ml of water, dried and the n-heptane was flashed from the dried solution to give the desired ester in a yield of 99% and a purity of 96%.
Mehod_B, in the presence of an onium compound.
The experiment ciescribed in section A of this example was repeated in the presence of 2 %m of tetra-n-butylammonium chloride, calculated on 3-phenoxybenzaldehyde. After two hours the ester was obtained in a yield of 99% with a purity of 94%.
Method C, in the presence of a non-ionic surface-active agent.
2~ The experiment described in section A of this Example was repeated in the presence of 10 %m of "Dobanol 91-6" ( for meaning il22224 of this word, see Table II), calculated on 3-phenoxybenzaldehyde.
After three hours' stirring the reaction mixture was warmed to a temperature between 40 and 50C and filtered. An amount of 50 ml of ethanol was added (to break the emulsion for~ed) tG the filtrate and the filtrate was washed twice with 50 ml of a 1 M aqueous solution of sodium bicarbonate, once with 50 ml of water, d~ied and the n-heptane was flashed from the dried solution to give the ester in a yield of 98% and a purity of 97%.
The above results are summarised in the following Table IV.
Table IV
Exp. Catal~st Reaction yield of Purity of no. time, h ester, % ester, %
name amoUn~ ol on aldehyde_ ________ ________ ___._____ 1 none - 45 99 96 2 tetra-n-butylammo- 2 2 99 94 ~ium c~loridel 3 Dobanol 91-6 ) 10 3 98 97 _______________________________________________________________ 1) for explanation of this word, see Table II.
EXAMPLE V
Pr_~ara_ion_gf_a-c~ano_~_~henoxybenzyl 2-(4-chloro~hen~l)__ ~-m_th~lbu anoate_in_th__~resenc~ of_various solvents and _glid__~an_de A 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10.0 or 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl 1~222~4 chloride, 12 mmol of sodium cyanide, 0.02 ml of water and 20 ml of an aprotic solvent. The molar ratio of water to sodium cyanide was 0.105, solid NaCN being present. The reaction mixture was stirred and analysed. Thirteen experiments were conducted in this manner, see Table V, stating which solvents were used.
Experiments 2,3,4,8 and 9 were conducted with 10.0 and the other experiments with 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl chloride. The petroleum ether used in experiment 3 consisted of 97% by weight of alkanes and 3% by weight of benzene and had a boiling range at atmospheric pressure between 62 and 82C. The ester remained in solution during the reaction in experiments 3 and 4. The reaction mixture obtained in ex-periment 4 was fiitered and the cyclohexane was flashed from the filtrate to give the ester wanted as a colourless oil in ~uantitative yield. Table V also presents the yields of the desired ester. Comparison of the yields shows that the alkanes and cyclohexane are the best solvents.
Table V
Experiment Solvent Reaction time, Yield of ester, no h %
______ ___ ___________________ ______________ _______________ 1 n-heptane 1.0 more than 99 2 2,4,4-trimethylpentane 1 92 3 petroleum ether 1 91 4 cyclohexane 1 80 3 more than 99 toluene 3 38 6 dichloromethane 2 34 7 o-dichlorobenzene 2 59 8 diethyl ether 3 54 9 diisobutyl ketone 20 80 nitromethane 5 5 11 1,4-dioxane 18 0 12 N,N-dimethylformamide 5 5 13 dimethylsulp~xide 2 _______________________________________________________________ ~122Z24 EXAMPLE VI
Pre~aration of ~-cyano-~-~henox~enz~l 2-(4-chloro~hen~l)-___ ______________ ____ _ _____ ____ ____ ________ ___ _ _ ~-meth~1butanoate in the ~resence of soaid c~anide ~ 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl chloride, 12 mmol of sodium cyanide, 20 ml of toluene, a phase trans~er catalyst, and water. The mixture thus ~ormed was stirred for varying periods of time and subsequently analysed. Six experiments were conducted in this manner, and the results are shown in Table VI, stating which catalysts and how much water was added, i~ any. The catalysts were employed in an amount of 0.20 mmol.
Table VI
___________________________________________________________________ Exp~ Catalyst Water Molar ratio Reaction Yield o~
no. added water to time, h ester, %
ml NaCN
___ _____________________ ________________________ _________ 1 1,4,7,10,13,16-he- - 0.012 2 60 xaoxacyclooctadecane 20 91 2 ditto 0.02 0.105 3 100 3 ditto 1.00 4.64 2 95 4 tetra-n-butylammonium 0.012 2 30 bromide 22 32 ditto 0.~2 0.105 2 81 6 ditto 1.00* 4.64 2 71 _________________________________________________________________ For the sake of comparison these 2 experiments had no solid cyanide present.
~122Z24 The sodium cyanide used consisted of particles having a largest dimension of 0.5 mm and contained ~.44% by weight of water. The molar ratio of water to sodium cyanide has been caleulatec~ taking into account the water present in the sodium cyanide and the water added, if any. ~or comparison it may be stated th~t the molar ratio of water to sodium cyanide in a saturated aqueous solution of sodium cyanide having a temperature of 23C is 4.1.
Column 1 in Table I states the number of the experiment, column 2 the catalyst, column 4 the amount of water added to the starting mixture (excluding the water present in the sodium cyanide) and column 5 the reaction time. The yield of the 1~2~:~24 ~esired ester is presented in column 6. The sodium cyanide was completely dissolved.
EXAMPLE II
Pre~ara_ic,n_of__c~ano-~-~henox~benz~l 2-(2l2-dichloro-v_n~ -dimeth~ac~cao~ro~anecarbox~la e_in the_~re_en_e of n-he~tane __ _____ ___ _ A 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, an amount of 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropanecar-bonyl chloride, 12 mmol of sodium cyanide, water, a catalyst, if any and 20 mi of n-heptane The mixture thus formed was stirred. Six experiments were carried out in this manner, see Table II. Column 3,4 and 5 state the amounts of cata-lyst~ water and acyl chloride added. The yield of the desired ester is presented in column 7.
~12Z224 Table II
_______________________________________________________________ E Catalyst Water Acyl Reaction Yield of P -------_____-_ ----- added chloride, time, ester, %
no. name ~mount ml mmol h %mol on ___ ___________ _aad_h~de ____ ________ _______ _________ 1) 1 - - 1.0 10.2 3 49 2 methyl-tri-2 5 1.0 10.2 1 96 m~thyl~eptyl-ammonium chloride 3 tet~a-n-butyl- 2 1.0 10.5 1 90 Ammonium chloride 4 Amb2e~1ite IRA '(1 gram)l.0 10,5 5 95 Dobanol 91-63) 2 1.0 10.0 2 80 6 1,4,7,10,13,16- 2 1.0 10.0 2 76 ~5 hexaoxacycloocta-decane ____________________ ________________________________________ 1) not according to the invention 2) a trade mark for a strongly basic anion exchange resin having a styrene/divinylbenzene copolymer as polymer matrix and a quaternary ammonium group as ion-active group.
The chloride form was used.
3) a trade mark for a non-ionic surface-active agent formed from a C9-Cll alcohol mixture and containing an a~erage of 6 ethyleneoxy units, the alcohol mixture consists oP 85%
n-alkanols and 15g 2-alkylalkanols.
EXAMPLE III
Pre~arat_on_Qf -c~ano-3-~henox~benz~l 2~2~3-tetrameth~l-c~vclopro~anecarbox~late in the ~resence of n-he~tane.
___ __ _________ ____________ _______________ ____ Methods A and B as indicated below were employed to prepare this ester. This example demonstrates that a gradual addition of the acid chloride to the reaction mixture during a period of 0.5 t~ 2 hours produces marked increases in yield at the end of that period.
Method A
A 50 ml round-bottomed flask equipped with a magneti~
stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10 mmol of 2,2,3,3-tetramethylcyclopropanecarbonyl chloride, 12 mmol of sodium cyanide, 1.00 ml of uater, a catalyst, if any, and 20 ml of n-heptane. The molar ratio of water to NaCN
was 4.64, solid NaCN being absent. The catalyst was added in an amount of 0.20 m~ol. The nixture thus formed was stirred for 1.5 hours and analysed.
Method B (gradual addition of acid chloride) The flask use~ for method A was charged with 10 mmol of 3-phenoxybenzaldehyde, 12 mmol of sodium cyanide, 10 ml of n-heptane, 1.00 ml of water and 0.20 m~ol of a catalyst, if any, the molar ratio of water to NaCN being 4.64.
An amount of 10 mmol of 2,2,3,3-tetramethylcyclopropane-carbonyl chloride dissolved in 10 ml of n-heptane was introduced into the flask during a period of 70-75 min.
The yield of the ester was determined at the end of this period.
112Z;~2~
Five experiments were carried out in this manner.
Table III states the catalysts u,ed, if any. This Table al~o presents the yield of the desired ester.
Table III
Exp. Catalyst Yield of ester, %
no. Method A Method B
______________________________ ________ _________ l*) none 17 40 21,4,7,10,13,16-hexaoxa- 18 97 cyclooctadecane 3 tetra-n-butylammonium chloride 20 98 4 methyl-t~i-2-methylheptyl- 18 96 ammonium chloride Dobanol 91-6 ) 44 98 ______________________________________________________ not according to the invention ) for explanation of this word, see Table II.
The amounts of the catalysts used were 2%m in the experiments 2-4 and 10 %m in experiment 5, calculated on 3-phenoxybenzaldehyde.
The reaction mixture obtained in experiment 4, method B, was filtered and the filtrate washed twice with 20 ml of a 1 M aqueous solution of sodium bicarbonate and once with 20 ml of water. The washed filtrate was dried and the n-hep-tane was flashed from the dried filtrate to obtain the ester as a pale yellow oil. This oil was dissolved in 2.5 ml of methanol at 23 C and the solution obtained was cooled to a temperature of ~0C to give a precipitate of the ester. The ester was filtered and had a purity of more than 98%.
EXAMPLE IV
Pre~aration of ~-c2ano-3-~henoxybenzyl 2-~4-chloro~hen~1)-3-meth~lbutanoate on an enlarged s_aae Methods A (not according to the invention), B and C were compared for the preparation of the desiréd ester.
Method Al in the absence of a phase transfer catalyst.
A 500 ml round-bottomed flask equipped with a paddle stirrer was charged with 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 a temperature between 40 and 50C
and filtered. The filtrate was washed twice with 50 ml of a 1 M aqueous sodium bicarbonate solution, once with 50 ml of water, dried and the n-heptane was flashed from the dried solution to give the desired ester in a yield of 99% and a purity of 96%.
Mehod_B, in the presence of an onium compound.
The experiment ciescribed in section A of this example was repeated in the presence of 2 %m of tetra-n-butylammonium chloride, calculated on 3-phenoxybenzaldehyde. After two hours the ester was obtained in a yield of 99% with a purity of 94%.
Method C, in the presence of a non-ionic surface-active agent.
2~ The experiment described in section A of this Example was repeated in the presence of 10 %m of "Dobanol 91-6" ( for meaning il22224 of this word, see Table II), calculated on 3-phenoxybenzaldehyde.
After three hours' stirring the reaction mixture was warmed to a temperature between 40 and 50C and filtered. An amount of 50 ml of ethanol was added (to break the emulsion for~ed) tG the filtrate and the filtrate was washed twice with 50 ml of a 1 M aqueous solution of sodium bicarbonate, once with 50 ml of water, d~ied and the n-heptane was flashed from the dried solution to give the ester in a yield of 98% and a purity of 97%.
The above results are summarised in the following Table IV.
Table IV
Exp. Catal~st Reaction yield of Purity of no. time, h ester, % ester, %
name amoUn~ ol on aldehyde_ ________ ________ ___._____ 1 none - 45 99 96 2 tetra-n-butylammo- 2 2 99 94 ~ium c~loridel 3 Dobanol 91-6 ) 10 3 98 97 _______________________________________________________________ 1) for explanation of this word, see Table II.
EXAMPLE V
Pr_~ara_ion_gf_a-c~ano_~_~henoxybenzyl 2-(4-chloro~hen~l)__ ~-m_th~lbu anoate_in_th__~resenc~ of_various solvents and _glid__~an_de A 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10.0 or 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl 1~222~4 chloride, 12 mmol of sodium cyanide, 0.02 ml of water and 20 ml of an aprotic solvent. The molar ratio of water to sodium cyanide was 0.105, solid NaCN being present. The reaction mixture was stirred and analysed. Thirteen experiments were conducted in this manner, see Table V, stating which solvents were used.
Experiments 2,3,4,8 and 9 were conducted with 10.0 and the other experiments with 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl chloride. The petroleum ether used in experiment 3 consisted of 97% by weight of alkanes and 3% by weight of benzene and had a boiling range at atmospheric pressure between 62 and 82C. The ester remained in solution during the reaction in experiments 3 and 4. The reaction mixture obtained in ex-periment 4 was fiitered and the cyclohexane was flashed from the filtrate to give the ester wanted as a colourless oil in ~uantitative yield. Table V also presents the yields of the desired ester. Comparison of the yields shows that the alkanes and cyclohexane are the best solvents.
Table V
Experiment Solvent Reaction time, Yield of ester, no h %
______ ___ ___________________ ______________ _______________ 1 n-heptane 1.0 more than 99 2 2,4,4-trimethylpentane 1 92 3 petroleum ether 1 91 4 cyclohexane 1 80 3 more than 99 toluene 3 38 6 dichloromethane 2 34 7 o-dichlorobenzene 2 59 8 diethyl ether 3 54 9 diisobutyl ketone 20 80 nitromethane 5 5 11 1,4-dioxane 18 0 12 N,N-dimethylformamide 5 5 13 dimethylsulp~xide 2 _______________________________________________________________ ~122Z24 EXAMPLE VI
Pre~aration of ~-cyano-~-~henox~enz~l 2-(4-chloro~hen~l)-___ ______________ ____ _ _____ ____ ____ ________ ___ _ _ ~-meth~1butanoate in the ~resence of soaid c~anide ~ 50 ml round-bottomed flask equipped with a magnetic stirrer was charged with 10 mmol of 3-phenoxybenzaldehyde, 10.5 mmol of 2-(4-chlorophenyl)-3-methylbutanoyl chloride, 12 mmol of sodium cyanide, 20 ml of toluene, a phase trans~er catalyst, and water. The mixture thus ~ormed was stirred for varying periods of time and subsequently analysed. Six experiments were conducted in this manner, and the results are shown in Table VI, stating which catalysts and how much water was added, i~ any. The catalysts were employed in an amount of 0.20 mmol.
Table VI
___________________________________________________________________ Exp~ Catalyst Water Molar ratio Reaction Yield o~
no. added water to time, h ester, %
ml NaCN
___ _____________________ ________________________ _________ 1 1,4,7,10,13,16-he- - 0.012 2 60 xaoxacyclooctadecane 20 91 2 ditto 0.02 0.105 3 100 3 ditto 1.00 4.64 2 95 4 tetra-n-butylammonium 0.012 2 30 bromide 22 32 ditto 0.~2 0.105 2 81 6 ditto 1.00* 4.64 2 71 _________________________________________________________________ For the sake of comparison these 2 experiments had no solid cyanide present.
~122Z24 The sodium cyanide used consisted of particles having a largest dimension of 0.5 mm and contained ~.44% by weight of water. The molar ratio of water to sodium cyanide has been caleulatec~ taking into account the water present in the sodium cyanide and the water added, if any. ~or comparison it may be stated th~t the molar ratio of water to sodium cyanide in a saturated aqueous solution of sodium cyanide having a temperature of 23C is 4.1.
Claims (21)
1. Process for the preparation of an ester of the general formula:- II
wherein R is an optionally substituted alkyl or cycloalkyl group and A is phenoxy, phenylthio or benzyl , which comprises reacting a benzaldehyde of the formula:- III
with an acyl halide of the formula R.CO.Hal (wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide, a substantially water-immiscible aprotic solvent and a phase transfer catalyst.
wherein R is an optionally substituted alkyl or cycloalkyl group and A is phenoxy, phenylthio or benzyl , which comprises reacting a benzaldehyde of the formula:- III
with an acyl halide of the formula R.CO.Hal (wherein Hal is bromide or chloride) in the presence of water, a water-soluble cyanide, a substantially water-immiscible aprotic solvent and a phase transfer catalyst.
2. Process as claimed in claim 1, in which the phase transfer catalyst is an onium compound, a macrocyclic polyether, or a surface-active agent.
3. Process as claimed in claim 2, in which the onium compound is a quaternary onium compound of the general formula wherein X represents a nitrogen, phosphorus or arsenic atom, R1, R2, R3 and R4 each an alkyl, aralkyl, alkaryl or aryl group and Y a monovalent ion, or a sulphonium compound of the general formula wherein R5, R6 and R7 each represents an alkyl group and Y a monovalent ion.
4. Process as claimed in claim 2 or 3 wherein the phase transfer catalyst is a quaternary ammonium compound.
5. Process as claimed in claim 2, in which the surface-active agent is a poly(alkyleneoxy)-derivative.
6. Process as claimed in claim 5, in which the poly(alkyleneoxy)-derivative is formed by reacting an alkanol of 8-20 carbon atoms with ethylene oxide or propylene oxide.
7. Process as claimed in claim 2 or 3, in which the molar ratio of the amount of phase transfer catalyst to the amount of benzaldehyde of the general formula III is from 1:5 to 1:500.
8. Process as claimed in claim 2 or 3, which is conducted at a temperature in the range of from 10°C to 50°C.
9. Process as claimed in claim 2, in which the substantially water-immiscible aprotic solvent is an alkane or cycloalkane or a mixture thereof, or an aromatic or chlorinated hydrocarbon.
10. Process as claimed in claim 9, in which the alkane is n-heptane.
11. Process as claimed in claim 9, in which the aromatic hydrocarbon is toluene or xylene.
12. Process as claimed in claim 2 or 3, which is conducted in the presence of solid water-soluble cyanide.
13. Process as claimed in claim 2 or 3, in which the starting molar ratio of the amount of water to the total amount of water-soluble cyanide is higher than 0.05.
14. Process as claimed in claim 2, in which the molar ratio of the amount of acyl halide of the general formula RC(O)Hal to the amount of the benz-aldehyde of the general formula III is in the range of from 1.1:1.0 to 1.0:1Ø
15. Process as claimed in claim 14, in which the molar ratio of the amount of acyl halide of the general formula RC(O)Hal to the amount of benzaldehyde is 1:1 or slightly in excess thereof.
16. Process as claimed in claim 2 or 3, in which the water-soluble cyanide is sodium cyanide.
17. Process as claimed in claim 2 or 3, in which A in the general formula II and III is a phenoxy group.
18. Process as claimed in claim 2 or 3 in which Hal in the general formula RC(O)Hal represents a chlorine atom.
19. Process as claimed in claim 2 or 3, in which the group R in the general formula II and in RC(O)Hal is a 1-(4-chlorophenyl)2-2 methylpropyl group, a 2,2,3,3-tetra-methylcyclopropyl group, or a 2-(2,2-dichlorovinyl)-3,3-dimethylcyclopropyl group.
20. Process as claimed in claim 2 or 3 , which is carried out by placing together the total amounts of the benzaldehyde, the acyl halide, the water, the water-soluble cyanide and the substantially water-immiscible aprotic solvent, and stirring the mixture thus formed.
21. Process as claimed in claim 2 or 3, which is carried out by gradual addition of the acyl halide to a stirred mixture obtained by placing together the benzaldehyde, the water, the water-soluble cyanide and the substantially water-immiscible aprotic solvent.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8045/76 | 1976-03-01 | ||
| GB8046/76 | 1976-03-01 | ||
| GB804576 | 1976-03-01 | ||
| GB804676 | 1976-03-01 | ||
| GB8044/76A GB1540632A (en) | 1976-03-01 | 1976-03-01 | Preparation of pesticidal benzyl esters |
| GB8044/76 | 1976-03-01 |
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|---|---|
| CA1122224A true CA1122224A (en) | 1982-04-20 |
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|---|---|---|---|
| CA000271451A Expired CA1122224A (en) | 1976-03-01 | 1977-02-09 | Preparation of pesticidal benzyl esters |
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| DE (1) | DE2708590C2 (en) |
| DK (1) | DK155882C (en) |
| EG (1) | EG13756A (en) |
| ES (1) | ES456367A1 (en) |
| FI (1) | FI65989C (en) |
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| HU (1) | HU181632B (en) |
| IE (1) | IE44059B1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US4153626A (en) | 1977-12-14 | 1979-05-08 | Shell Oil Company | Preparation of α-cyanobenzyl esters |
| JPS54103831A (en) * | 1978-01-27 | 1979-08-15 | Sumitomo Chem Co Ltd | Separation of stereoisomers of higher active cyanoo33 phenoxybenzyl 22*44chlorophenyl**isovalerate |
| FR2416219A1 (en) * | 1978-01-31 | 1979-08-31 | Roussel Uclaf | ESTERS OF OPTICALLY ACTIVE SUBSTITUTE ACETIC ACID AND RACEMIC OR OPTICALLY ACTIVE SUBSTITUTE BENZYL ALCOHOL, HAVING INSECTICIDAL PROPERTIES, THEIR PREPARATION PROCESS AND THE COMPOSITIONS CONTAINING THEM |
| CA1142953A (en) * | 1979-04-03 | 1983-03-15 | Dale G. Brown | Process for the preparation of pesticidal esters of certain carboxylic acids using phase transfer catalysts |
| DE2936864A1 (en) * | 1979-09-12 | 1981-04-02 | Bayer Ag, 5090 Leverkusen | (+ -) - TRANS-3- (E, Z-2-CHLOR-2- (4-CHLORPHENYL) -VINYL) -, 2,2-DIMETHYL-CYCLOPROPAN-CARBONIC ACID - (+ -) - (ALPHA) -CYANO -3-PHENOXY-4-FLUOR-BENZYL) -ESTERS, THE INDIVIDUAL E- AND Z-ISOMERS, METHOD FOR THE PRODUCTION OF THESE COMPOUNDS AND THEIR USE AS EECTOPARASITICIDES |
| JPS6245083U (en) * | 1985-09-06 | 1987-03-18 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS515450B1 (en) * | 1971-06-29 | 1976-02-20 |
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1977
- 1977-02-09 CA CA000271451A patent/CA1122224A/en not_active Expired
- 1977-02-25 NL NLAANVRAGE7702022,A patent/NL190068C/en not_active IP Right Cessation
- 1977-02-25 PH PH19496A patent/PH13719A/en unknown
- 1977-02-26 EG EG119/77A patent/EG13756A/en active
- 1977-02-28 ES ES456367A patent/ES456367A1/en not_active Expired
- 1977-02-28 BR BR7701218A patent/BR7701218A/en unknown
- 1977-02-28 SE SE7702168A patent/SE442633B/en not_active IP Right Cessation
- 1977-02-28 HU HU77SE1856A patent/HU181632B/en unknown
- 1977-02-28 PT PT66242A patent/PT66242B/en unknown
- 1977-02-28 IL IL51567A patent/IL51567A/en unknown
- 1977-02-28 FI FI770632A patent/FI65989C/en not_active IP Right Cessation
- 1977-02-28 SU SU772455682A patent/SU685145A3/en active
- 1977-02-28 GR GR52866A patent/GR62438B/en unknown
- 1977-02-28 AT AT132777A patent/AT349454B/en not_active IP Right Cessation
- 1977-02-28 DE DE2708590A patent/DE2708590C2/en not_active Expired
- 1977-02-28 FR FR7705746A patent/FR2342960A1/en active Granted
- 1977-02-28 IT IT20781/77A patent/IT1075420B/en active
- 1977-02-28 RO RO7789558A patent/RO71762A/en unknown
- 1977-02-28 IN IN291/CAL/77A patent/IN143789B/en unknown
- 1977-02-28 AR AR266711A patent/AR227121A1/en active
- 1977-02-28 BG BG7735547A patent/BG27893A3/en unknown
- 1977-02-28 JP JP52020383A patent/JPS6017781B2/en not_active Expired
- 1977-02-28 AU AU22769/77A patent/AU507462B2/en not_active Expired
- 1977-02-28 NZ NZ183461A patent/NZ183461A/en unknown
- 1977-02-28 DD DD7700197602A patent/DD128362A5/en unknown
- 1977-02-28 MX MX775480U patent/MX4513E/en unknown
- 1977-02-28 YU YU534/77A patent/YU40667B/en unknown
- 1977-02-28 DK DK087977A patent/DK155882C/en active
- 1977-02-28 NO NO770673A patent/NO145234C/en unknown
- 1977-02-28 LU LU76861A patent/LU76861A1/xx unknown
- 1977-02-28 IE IE426/77A patent/IE44059B1/en not_active IP Right Cessation
- 1977-02-28 CS CS771318A patent/CS197286B2/en unknown
- 1977-02-28 CH CH250677A patent/CH632237A5/en not_active IP Right Cessation
- 1977-03-01 OA OA56084A patent/OA05582A/en unknown
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