CA1210403A - Process for the preparation of benzoxazolyl- and benzothiazolyl-oxyphenoxypropionic acid derivatives - Google Patents
Process for the preparation of benzoxazolyl- and benzothiazolyl-oxyphenoxypropionic acid derivativesInfo
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- CA1210403A CA1210403A CA000438222A CA438222A CA1210403A CA 1210403 A CA1210403 A CA 1210403A CA 000438222 A CA000438222 A CA 000438222A CA 438222 A CA438222 A CA 438222A CA 1210403 A CA1210403 A CA 1210403A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D263/00—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings
- C07D263/52—Heterocyclic compounds containing 1,3-oxazole or hydrogenated 1,3-oxazole rings condensed with carbocyclic rings or ring systems
- C07D263/54—Benzoxazoles; Hydrogenated benzoxazoles
- C07D263/58—Benzoxazoles; Hydrogenated benzoxazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
- C07D277/60—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings condensed with carbocyclic rings or ring systems
- C07D277/62—Benzothiazoles
- C07D277/68—Benzothiazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
- Thiazole And Isothizaole Compounds (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Catalysts (AREA)
- Plural Heterocyclic Compounds (AREA)
Abstract
Abstract of the disclosure:
Preparation of compounds of the formula in which X is oxygen or sulfur, R is halogen or CF3 and COOR1 is an ester group, by reaction of compounds of the formula with compounds of the formula
Preparation of compounds of the formula in which X is oxygen or sulfur, R is halogen or CF3 and COOR1 is an ester group, by reaction of compounds of the formula with compounds of the formula
Description
- 2 - HOE 82/F 197 Subject of the present invention is a process for the preparation of compounds of the formula I
R - ~ ~ ^ ~ -O-CT~-C~OR
in which X is oxygen or sulfur R is halogen or CF3, and R1 is (C1-C12)alkyl optionally substituted by one or two halogen atoms or alkoxy, alkylthio, alkoxy-(C2-C4)alkoxy each having from 1 to 6 carbon atoms, halo-(C1 or C2)-alkoxy or methoxyethoxyethoxy; or is (C3-C6)alkenyl, (C3-C6)-alkinyl, (C5 or C6)cycloalkyl, (C1-C4)alkoxy-carbonyl-(C1 or C2)alkyl or the group -N-C/~C1-C4)alkyl72.
Compounds of the formula I are known for example from UOS. Patent No. 4,130,413, British Patent No.
2,046,753 and European Patent No. 2,800; they are distinguished by a selective herbicidal action against weed grasses. With respect to the individual meanings of R1, reference is made especially to the compounds described therein.
Especially preferred is (C1-C12)alkyl. By halogen, there is to be understood preferably fluorine, chlorine or bromine.
According to the above cited state of the art the compounds are prepared by reaction of 2-halobenzazoles of the formula II with substituted phenols of the formula III in the presence of acid binders:
~ f ~ Hal + HO - ~ O-CH-COOR
II III
For the reaction, inert aprotic solvents such as
R - ~ ~ ^ ~ -O-CT~-C~OR
in which X is oxygen or sulfur R is halogen or CF3, and R1 is (C1-C12)alkyl optionally substituted by one or two halogen atoms or alkoxy, alkylthio, alkoxy-(C2-C4)alkoxy each having from 1 to 6 carbon atoms, halo-(C1 or C2)-alkoxy or methoxyethoxyethoxy; or is (C3-C6)alkenyl, (C3-C6)-alkinyl, (C5 or C6)cycloalkyl, (C1-C4)alkoxy-carbonyl-(C1 or C2)alkyl or the group -N-C/~C1-C4)alkyl72.
Compounds of the formula I are known for example from UOS. Patent No. 4,130,413, British Patent No.
2,046,753 and European Patent No. 2,800; they are distinguished by a selective herbicidal action against weed grasses. With respect to the individual meanings of R1, reference is made especially to the compounds described therein.
Especially preferred is (C1-C12)alkyl. By halogen, there is to be understood preferably fluorine, chlorine or bromine.
According to the above cited state of the art the compounds are prepared by reaction of 2-halobenzazoles of the formula II with substituted phenols of the formula III in the presence of acid binders:
~ f ~ Hal + HO - ~ O-CH-COOR
II III
For the reaction, inert aprotic solvents such as
- 3 - H~E &2/~
aliphat~c or aromatic hydrocarbons (benzene~ tGluenet xylene), acid nitriles (acetonitrile), ketone3 (acetone) or acid arnides (~MF, DMS0) are used. For several reason~, however, these solvents have disadvantages.
DMF, DMS0 and acetonitrile ~ive hi.gh yields but are rather expensive and due to their relatively low MAC
(maximurll allo~rable concentration) values not quite harM-less from the viewpoint of industrial hygiene. Ketone.s do not give optimum yields because of their lo~l boiling poink. Non-polar solvents SUCh as tol~ene and xylene give products of insufficient purity in l.ikewise unsatisfactory y.ields despite extremely long reaction tirres .
It was therefore the object of ~he present invention to provide a process which avoids the above disadvan~a~es.
Surprisingly, it has been ~ound that the compounds II and III can be converted to the compounds I with high yields in non-polar solvents when operating in the presence of a catalyst.
~ ubject of the invention is therefore a process for the preparation of cornpounds of the formula I by reaction of compoul1ds of the formula II with compounds of the formu].a III in the presence of an inert non-polar solvent and an acid~binding agent which cGmprlses carrying out the reactiol1 in the presence of a catalyst selected frorn the group of ouaternary ammonium and phos~
phonium bases, polyalkylene glycols or their lower alkyl ethers.
The catalysts are used in amounts of from 0.05 to 1.0, preferably 0.1 to 0.5lmol ~ relative to the componer.t II. The quaternarr ammonium and phosphonium bases con'cain alky:L, benæyl or phenyl ~roups as or~anic radicals ancl are generally present as halides. Examples are tetrabutyl ammonium bromide or iodide, trietl1yl benzyl arnmonium chlori.de, tetraoctyl phosphonium chlorid~, tetrabutyl phosphonium bromide, triphenyl ~ Q 3
aliphat~c or aromatic hydrocarbons (benzene~ tGluenet xylene), acid nitriles (acetonitrile), ketone3 (acetone) or acid arnides (~MF, DMS0) are used. For several reason~, however, these solvents have disadvantages.
DMF, DMS0 and acetonitrile ~ive hi.gh yields but are rather expensive and due to their relatively low MAC
(maximurll allo~rable concentration) values not quite harM-less from the viewpoint of industrial hygiene. Ketone.s do not give optimum yields because of their lo~l boiling poink. Non-polar solvents SUCh as tol~ene and xylene give products of insufficient purity in l.ikewise unsatisfactory y.ields despite extremely long reaction tirres .
It was therefore the object of ~he present invention to provide a process which avoids the above disadvan~a~es.
Surprisingly, it has been ~ound that the compounds II and III can be converted to the compounds I with high yields in non-polar solvents when operating in the presence of a catalyst.
~ ubject of the invention is therefore a process for the preparation of cornpounds of the formula I by reaction of compoul1ds of the formula II with compounds of the formu].a III in the presence of an inert non-polar solvent and an acid~binding agent which cGmprlses carrying out the reactiol1 in the presence of a catalyst selected frorn the group of ouaternary ammonium and phos~
phonium bases, polyalkylene glycols or their lower alkyl ethers.
The catalysts are used in amounts of from 0.05 to 1.0, preferably 0.1 to 0.5lmol ~ relative to the componer.t II. The quaternarr ammonium and phosphonium bases con'cain alky:L, benæyl or phenyl ~roups as or~anic radicals ancl are generally present as halides. Examples are tetrabutyl ammonium bromide or iodide, trietl1yl benzyl arnmonium chlori.de, tetraoctyl phosphonium chlorid~, tetrabutyl phosphonium bromide, triphenyl ~ Q 3
- 4 - H0~ 82/F_197 butyl phosphonium bromide, trilauryl methyl phosp7nonium iodide, tributyl methyl phosphonium iodide and tributyl hexadecyl phosphonium bromide. Furthermore suitable are cyclic polyethylene glycols (so-called crown ethers) and long-chain polypropylene glycols, and especially poly-ethylene glycols having a molecular weight of from about 400 to about 6,ooo and the mono- and di-lower alkyl ethers thereof. Compounds of this kind are generally known in organic chemistry under the name of phase transfer catalysts, because they accelerate reactions in the two-phase system water/organic solvent.
Because of the better phase separation in aqueous work-up, long-chain or cyclic polyalkylene glycols having a molecular weight of from about l,000 to about 3,000 are preferably used.
As solvents, aromatic hydrocarbons liquid at room temperature are used which may contain halogen, for example toluene, xylene, cumene, mesitylene, chloro-benzene or o-dichlorobenzene.
Suitable acid-binding agents are generally organic and inorganic bases, preferably however alkali metal carbonates or bicarbonates, for example those of potassium and sodium. In order to avoid hydrolysis and saponification reactions which result in reduced yields, reaction water has to be removed when using bicarbonates.
Furthermore, it must be noted that at temperatures above about 90C water is formed due to thermal instability from the hydrogenocarbonates used or formed from the alkali metal carbonates. The water can be distilled off azeotropically either under normal pressure, under reduced pressure, or with the aid of an inert gas current.
In this connection reference is made to Synthesis 1980, 921, where the reaction of 2-chloropyridines and 2-chloroquinolines with phenols in a system of water/toluene or benzene in the presence of phase transfer catalysts is described. In the process ~ ~7~
Because of the better phase separation in aqueous work-up, long-chain or cyclic polyalkylene glycols having a molecular weight of from about l,000 to about 3,000 are preferably used.
As solvents, aromatic hydrocarbons liquid at room temperature are used which may contain halogen, for example toluene, xylene, cumene, mesitylene, chloro-benzene or o-dichlorobenzene.
Suitable acid-binding agents are generally organic and inorganic bases, preferably however alkali metal carbonates or bicarbonates, for example those of potassium and sodium. In order to avoid hydrolysis and saponification reactions which result in reduced yields, reaction water has to be removed when using bicarbonates.
Furthermore, it must be noted that at temperatures above about 90C water is formed due to thermal instability from the hydrogenocarbonates used or formed from the alkali metal carbonates. The water can be distilled off azeotropically either under normal pressure, under reduced pressure, or with the aid of an inert gas current.
In this connection reference is made to Synthesis 1980, 921, where the reaction of 2-chloropyridines and 2-chloroquinolines with phenols in a system of water/toluene or benzene in the presence of phase transfer catalysts is described. In the process ~ ~7~
- 5 - HOE 82/F 197 of the invention the catalysts used do not act as phase transfer catalysts due to lack of a second liquid phase.
It was surprising that the catalysts have an excellent activity also in a liquid/solid system.
The process of the invention is carried out in a temperature range of from 30 to 250C, preferably 50 to 180C, or the boiling point of the solvent. The sequence of addition of the reactants is not critical,generally, the process is carried out as ~ollows: the 2-halobenzazole and the base is introduced together with the catalyst into the solvent chosen, and component III
is added dropwise under reaction conditions. The slight excess o~ component III generally used is easily removed by cooling the batch after the reaction is complete and treating it with dilute alkali. After neutralization and distillation of the solvent which can be reused, the products of the process are obtained ln nearly quantita-tive yields and a purity of about 95 % (determined by gas chromatography).
In the case of the benzoxazole, excellent yields are obtained at temperatures of 90C even without catalyst, if the water formed by thermal cleavage from the acld-binding agent is removed immediately in the manner as indicated above.
The following examples illustrate the invention without limiting it in its scope.
E X A M P L E
Ethyl-2-[4-(6-chloro-2-benzothiazolyloxy)-phenoxy]
-propanoate 30 a) 105.0 g (0~5 Mol) ethyl-2-(4-hydroxyphenoxy)-propanoate, 102.0 g (0.5 mol) 2,6-dichlorobenzo-thiazole, 70.5 g (0.51 mol) potassium carbonate and 0.22 g (o.6 mmol) tetra-n-butyl phosphonium bromide are united in 300 ml xylene and refluxed for 6.5 hours under a nitrogen atmosphere using a water separator. The cour-se of the reaction is supervised by thin-layer chromatography~ The reaction being complete, the batch ,, .
~12~L~14(1~;~
H!~J ~ r7 is cooled to ro(~m temperature. The salt portLon is fil-tered off, the filtrate is washed with 200 ml of uater and the organic phase is concentrated.
183.0 g (96.~% of theory) ethyl 2-[4-(6-chloro 2-~benzo-thiazolyloxy)-phenoxy]-propanoate, m.p. 53.0 - 54.0C, purity ~ 9'7%, are obtained.
b) 204 g (1 mol) 2,6-dichlorobenzo~hiazole, 99.4 g ~0,72 mol) potassium carbonate and 6 g (0.003 mol) polyethyle-ne glycol (MW 2,000) are introduced lnto 600 ml xylene and heated to 135-140C with vigorous stirring. 220.5 g (1.05 mol) ethyl-2-(4-hydroxyphenoxy)-propanoate are ad-ded dropwise under reflux and with clistilling-of'f of the water as an azeotropic mixture. Stirring is con~inued for 7 hours at 140C while continuing the removal of water. The batch is cooled and ~lashed once with lloO ml and once with 250 ml of 5 % sodium hydroxide solution.
After washing to neutral with dilute sodium dihydrogen phosphate solution, the xylene is distilled o~'. As residue, 3~3.G g (96.2 % of~ theory) ethyl-2-[4-(6-c~lloro-2-benzothiazolyloxy)-phenoxy]-propanoate, m.p. 53.4 -54.5C; are obtained the purity Or which according to GC
is 97.5 %.
c) 255.0 g (1.25 mols) 2,6-dichlorobenzothiazole, 124.4 g ~0.~ mol) potassium carbonàte, 7.5 g (0.001l mol) poly-ethylene glycol (M~l 2,000) and 750 rnl mesitylene areheated to about 160C with vigorous stirring. I~ithin 1 hour, 275.4 ~ (1.31 mols) ethyl-2-(4-h~droxyphenoxy) propanoate are added dropwise under reflux. Stirring is continued for a f~urther 3.5 hours under reflux, while constantly distillin~ off the water which forms as an azeotropic mixture. The batch is cooled~ washecl once ~ith 300 ml, then once with 200 ml of 5 % sodium hy-droxide solution, and subsequently washed with phosphate buffer (pH 4). The organic pha.se is separated and the xylene is distilled off'. lg8 ~ (93.9 ~ of theory) of ethyl-2-[4--(c, chloro~2-benzoth:laæolyloxy)-phenoxy3-propanoate are obta1ned the p~lrity of' whi~h is 94~3 lZ~0~3 d) 102.0 ~; (0.~ mol) 2,6-dichlorobenzothiazole and 100,1 g (1 mol) potassiurn bicarbonate are refluxed in 200 n~l of xylene. While maintaining a vigorous reflux, ~ solution of 110.25 g (0.525 mol) ethyl-2-[4-hydroxyphenoxy]-propanoate and 3 g (0.0015 mol) polyethylene glycol (l~5W 2,000) in 100 ml xylene is added within 1 hour.
Stirring is continued for a further 6.5 hours under re-f lux, whlle constantly disti]ling off the water formed as an azeotropic mixture. The reaction mixture is coo-led, ~rashed once with 100 ml of 5 % sodlum hydroxide so-lution and twice ~ith 100 ml each of ~rater. After having distilled o~f the xylene, 182.0 g (96.3 % of theory) ethyl-2~[4-(6-chloro~2-benzothiazolyloxy)-phenoxy3-propanoate are obtained l;he purity of which is 93.6 %.
.
Ethyl-2--~4--t6-chloro benzoxazolyloxy)-phenoxyl-propanoate a) 105.0 g (0.5 mol) ethyl-2-(4-hydroxyphenoxy)-propanoate, 94.0 g (0.5 mol ) 2,6-dichlorobenzoxazole, 7(),5 g (0.51 mol) potassiurn carbonate and 0.56 g (0.0025 mol) tric-thylbenzylammonium chloride are united ~n 300 ml of xylene and heated to 110C for 2 hours in a water separator. The course Or the reaction is supervi-sed by thin-layer chromatography. The reaction being complete, the batch is cooled to room temperature. The salt portion i8 sucti'on-filtered~ the filtrate is washed ~- ~ with 200 ml of water, and the organic phase is sepa~ ated and concentrated. Solvent residues are removed under highly reduced pressllre. 175~3 g (97.3 % of theory) ethyl 2--[4~(6-chloro~2-benzoxazolyloxy)-phenoxy]-propanoate rn.p. 81.5 - 83.0C are obtained, the purity ol which is 97.5 %-In analogous manner, but with the use of D(+)-ethyl-2-(ll-hydroxyphenoxy)-propanoate, D(~)-ethyl-~-[4-(6-ch:l.oro-2-benzoxazolyloxy)-phenoxy]-propanoate; [~]24,5 33.4O (c = 36.2, CHC:L3) is obtained wlth identical yiel~.
b) 188 ~; (l rnol) 2,6 dichlorobenzoxazole and 99~4 g (0~72 r~lol) potasslum carbonate in 600 ml xylene are heated to ~. ~Z~ 3 - 8 _ HOE _2/F 197 110C. Under sllghtly reduced pressure 216.3 ~ 03 ~Qolj ethyl-2-(4-hydroxyphenoxy)-propanoate are added drop~lise within 1/2 hour. During and after the addit~on the ~Jat~r which forms i3 distilled off. After about 2-3 hours the ~atch ls cooled, washcd ~ith 350 ml of water and twice with 200 ml each of 5 ~ sodium hydroxide soiu tiOIl. After having distilled off the sol~ent, 356.l~ g (98.5 % of theory) of ethyl~2-[4--(6-chloro--2-benzoxazolyloxy)-phenoxy]-propanoate, m.p. 82-~4C, are obtained as residue; the purity being ~ 98 %.
c) 188 g (1 mol) 2,6-dichlorobenzoxazole, 151.8 ~ (1.1 mols) potassium carbonate and 6 ~ (0~003 mol) poly-ethyleneglycol 25000 are introduced lnto 650 ml toluene and heated to 85C. Within abouc l hour 216.3 g (1.03 mol) ethyl-~-(4-hydroxyphenoxy)--propanoate are added dropwise. Stirring is continued for 6 hours at 85-88C, the batch is cooled, ~ashed once with llO0 ml and once with 250 ml of 5 % sodium hydroxide solution. After having distilled of~ the toluene, 352 g (97.3 % of theory) of ethy:'-2-l4-(~-chloro-2--benzoxazolyloxy)--phenoxy~-propanoate, m.p. 82-84C, are obtained as resldue, the purity being ~ 98 %.
d) 47.~ g (0.25 rnol) 2,6-dichlorobenzoxazole and 50.0 g (0.50 mol) potassium bicarbonate are introduced into 100 ml xylene and refluxed. l~hile rnaintalning a vigorous - reflux, a solutic)n of 54.1 g (0.257 mol) ethyl-2 (4-hydroxyphenoxy)propanoate and 1O5 g (0~0008 mol) polyethyleneglycol 2,000 in 50 ml xylene is added dropwise within 1 hour. The reaction is complete after 3.5 hours; the water ~rhich forms in the reaction is dlstilled off continuously. The reaction mixture is cooled~ washed twice with 75 ml of 5 % sodium hydroxide solution and once with 75 ml phosphate bu~er (pH 4j-After having distilled off the xylene, 87.o g (96~3 % of theory) ethyl-2-[4-(6-chloro-2-benzoxazyloxy)-phenoxy]-propanoate, m.pD 81.5-83C are obtained, the purity of which is 96.4 %.
According to Example la and 2a, respectively~ there are obtained:
, Ex. according catalysk Yield Purity (%) No. to Ex. (%) (acc. to GC)_ 3 1 a ethyl-trioctylphos- 97.4 95.9 phonium bromide 4 1 a trilaurylmethylphos- 93.7 96-3 phonium bromide 1 a tetraoctylphosphonium 96.o 96.9 chloride
It was surprising that the catalysts have an excellent activity also in a liquid/solid system.
The process of the invention is carried out in a temperature range of from 30 to 250C, preferably 50 to 180C, or the boiling point of the solvent. The sequence of addition of the reactants is not critical,generally, the process is carried out as ~ollows: the 2-halobenzazole and the base is introduced together with the catalyst into the solvent chosen, and component III
is added dropwise under reaction conditions. The slight excess o~ component III generally used is easily removed by cooling the batch after the reaction is complete and treating it with dilute alkali. After neutralization and distillation of the solvent which can be reused, the products of the process are obtained ln nearly quantita-tive yields and a purity of about 95 % (determined by gas chromatography).
In the case of the benzoxazole, excellent yields are obtained at temperatures of 90C even without catalyst, if the water formed by thermal cleavage from the acld-binding agent is removed immediately in the manner as indicated above.
The following examples illustrate the invention without limiting it in its scope.
E X A M P L E
Ethyl-2-[4-(6-chloro-2-benzothiazolyloxy)-phenoxy]
-propanoate 30 a) 105.0 g (0~5 Mol) ethyl-2-(4-hydroxyphenoxy)-propanoate, 102.0 g (0.5 mol) 2,6-dichlorobenzo-thiazole, 70.5 g (0.51 mol) potassium carbonate and 0.22 g (o.6 mmol) tetra-n-butyl phosphonium bromide are united in 300 ml xylene and refluxed for 6.5 hours under a nitrogen atmosphere using a water separator. The cour-se of the reaction is supervised by thin-layer chromatography~ The reaction being complete, the batch ,, .
~12~L~14(1~;~
H!~J ~ r7 is cooled to ro(~m temperature. The salt portLon is fil-tered off, the filtrate is washed with 200 ml of uater and the organic phase is concentrated.
183.0 g (96.~% of theory) ethyl 2-[4-(6-chloro 2-~benzo-thiazolyloxy)-phenoxy]-propanoate, m.p. 53.0 - 54.0C, purity ~ 9'7%, are obtained.
b) 204 g (1 mol) 2,6-dichlorobenzo~hiazole, 99.4 g ~0,72 mol) potassium carbonate and 6 g (0.003 mol) polyethyle-ne glycol (MW 2,000) are introduced lnto 600 ml xylene and heated to 135-140C with vigorous stirring. 220.5 g (1.05 mol) ethyl-2-(4-hydroxyphenoxy)-propanoate are ad-ded dropwise under reflux and with clistilling-of'f of the water as an azeotropic mixture. Stirring is con~inued for 7 hours at 140C while continuing the removal of water. The batch is cooled and ~lashed once with lloO ml and once with 250 ml of 5 % sodium hydroxide solution.
After washing to neutral with dilute sodium dihydrogen phosphate solution, the xylene is distilled o~'. As residue, 3~3.G g (96.2 % of~ theory) ethyl-2-[4-(6-c~lloro-2-benzothiazolyloxy)-phenoxy]-propanoate, m.p. 53.4 -54.5C; are obtained the purity Or which according to GC
is 97.5 %.
c) 255.0 g (1.25 mols) 2,6-dichlorobenzothiazole, 124.4 g ~0.~ mol) potassium carbonàte, 7.5 g (0.001l mol) poly-ethylene glycol (M~l 2,000) and 750 rnl mesitylene areheated to about 160C with vigorous stirring. I~ithin 1 hour, 275.4 ~ (1.31 mols) ethyl-2-(4-h~droxyphenoxy) propanoate are added dropwise under reflux. Stirring is continued for a f~urther 3.5 hours under reflux, while constantly distillin~ off the water which forms as an azeotropic mixture. The batch is cooled~ washecl once ~ith 300 ml, then once with 200 ml of 5 % sodium hy-droxide solution, and subsequently washed with phosphate buffer (pH 4). The organic pha.se is separated and the xylene is distilled off'. lg8 ~ (93.9 ~ of theory) of ethyl-2-[4--(c, chloro~2-benzoth:laæolyloxy)-phenoxy3-propanoate are obta1ned the p~lrity of' whi~h is 94~3 lZ~0~3 d) 102.0 ~; (0.~ mol) 2,6-dichlorobenzothiazole and 100,1 g (1 mol) potassiurn bicarbonate are refluxed in 200 n~l of xylene. While maintaining a vigorous reflux, ~ solution of 110.25 g (0.525 mol) ethyl-2-[4-hydroxyphenoxy]-propanoate and 3 g (0.0015 mol) polyethylene glycol (l~5W 2,000) in 100 ml xylene is added within 1 hour.
Stirring is continued for a further 6.5 hours under re-f lux, whlle constantly disti]ling off the water formed as an azeotropic mixture. The reaction mixture is coo-led, ~rashed once with 100 ml of 5 % sodlum hydroxide so-lution and twice ~ith 100 ml each of ~rater. After having distilled o~f the xylene, 182.0 g (96.3 % of theory) ethyl-2~[4-(6-chloro~2-benzothiazolyloxy)-phenoxy3-propanoate are obtained l;he purity of which is 93.6 %.
.
Ethyl-2--~4--t6-chloro benzoxazolyloxy)-phenoxyl-propanoate a) 105.0 g (0.5 mol) ethyl-2-(4-hydroxyphenoxy)-propanoate, 94.0 g (0.5 mol ) 2,6-dichlorobenzoxazole, 7(),5 g (0.51 mol) potassiurn carbonate and 0.56 g (0.0025 mol) tric-thylbenzylammonium chloride are united ~n 300 ml of xylene and heated to 110C for 2 hours in a water separator. The course Or the reaction is supervi-sed by thin-layer chromatography. The reaction being complete, the batch is cooled to room temperature. The salt portion i8 sucti'on-filtered~ the filtrate is washed ~- ~ with 200 ml of water, and the organic phase is sepa~ ated and concentrated. Solvent residues are removed under highly reduced pressllre. 175~3 g (97.3 % of theory) ethyl 2--[4~(6-chloro~2-benzoxazolyloxy)-phenoxy]-propanoate rn.p. 81.5 - 83.0C are obtained, the purity ol which is 97.5 %-In analogous manner, but with the use of D(+)-ethyl-2-(ll-hydroxyphenoxy)-propanoate, D(~)-ethyl-~-[4-(6-ch:l.oro-2-benzoxazolyloxy)-phenoxy]-propanoate; [~]24,5 33.4O (c = 36.2, CHC:L3) is obtained wlth identical yiel~.
b) 188 ~; (l rnol) 2,6 dichlorobenzoxazole and 99~4 g (0~72 r~lol) potasslum carbonate in 600 ml xylene are heated to ~. ~Z~ 3 - 8 _ HOE _2/F 197 110C. Under sllghtly reduced pressure 216.3 ~ 03 ~Qolj ethyl-2-(4-hydroxyphenoxy)-propanoate are added drop~lise within 1/2 hour. During and after the addit~on the ~Jat~r which forms i3 distilled off. After about 2-3 hours the ~atch ls cooled, washcd ~ith 350 ml of water and twice with 200 ml each of 5 ~ sodium hydroxide soiu tiOIl. After having distilled off the sol~ent, 356.l~ g (98.5 % of theory) of ethyl~2-[4--(6-chloro--2-benzoxazolyloxy)-phenoxy]-propanoate, m.p. 82-~4C, are obtained as residue; the purity being ~ 98 %.
c) 188 g (1 mol) 2,6-dichlorobenzoxazole, 151.8 ~ (1.1 mols) potassium carbonate and 6 ~ (0~003 mol) poly-ethyleneglycol 25000 are introduced lnto 650 ml toluene and heated to 85C. Within abouc l hour 216.3 g (1.03 mol) ethyl-~-(4-hydroxyphenoxy)--propanoate are added dropwise. Stirring is continued for 6 hours at 85-88C, the batch is cooled, ~ashed once with llO0 ml and once with 250 ml of 5 % sodium hydroxide solution. After having distilled of~ the toluene, 352 g (97.3 % of theory) of ethy:'-2-l4-(~-chloro-2--benzoxazolyloxy)--phenoxy~-propanoate, m.p. 82-84C, are obtained as resldue, the purity being ~ 98 %.
d) 47.~ g (0.25 rnol) 2,6-dichlorobenzoxazole and 50.0 g (0.50 mol) potassium bicarbonate are introduced into 100 ml xylene and refluxed. l~hile rnaintalning a vigorous - reflux, a solutic)n of 54.1 g (0.257 mol) ethyl-2 (4-hydroxyphenoxy)propanoate and 1O5 g (0~0008 mol) polyethyleneglycol 2,000 in 50 ml xylene is added dropwise within 1 hour. The reaction is complete after 3.5 hours; the water ~rhich forms in the reaction is dlstilled off continuously. The reaction mixture is cooled~ washed twice with 75 ml of 5 % sodium hydroxide solution and once with 75 ml phosphate bu~er (pH 4j-After having distilled off the xylene, 87.o g (96~3 % of theory) ethyl-2-[4-(6-chloro-2-benzoxazyloxy)-phenoxy]-propanoate, m.pD 81.5-83C are obtained, the purity of which is 96.4 %.
According to Example la and 2a, respectively~ there are obtained:
, Ex. according catalysk Yield Purity (%) No. to Ex. (%) (acc. to GC)_ 3 1 a ethyl-trioctylphos- 97.4 95.9 phonium bromide 4 1 a trilaurylmethylphos- 93.7 96-3 phonium bromide 1 a tetraoctylphosphonium 96.o 96.9 chloride
6 1 a polyethylene glycol 94.2 96.9 (MW 1,500)
7 1 a polyethylene glycol 95.9 96.8 (MW 3,000)
8 1 a polypropylene glycol 94.9 94.9 (rqW 2,000)
9 1 a polyethylene glycol 96.1 97.6 monomethyl ether (MW 1,900) 1 a polyethyleneglycol 96.2 98.2 :: dimethyl ether (MW 400) : 11 2 a tetrabutylammonium 99.2 97.2 bromide 12 2 a tetrabutylammonium 94 97.7 iodide 13 2 a tributylhexadecyl 95.3 96.2 phosphonium bromide 14 2 a polyethylene glycol 97.2 96.8 (rqW 1,500) 2 a polyethylene glycol 96.6 97-4 (MW 3,000) , . . .
4~3
4~3
-10- H0~ 82/F 137 Ex. accordin~ catalyst Yield Purity (%) No. to EY~. (%) (acc. ~o GC) . . _ ~ _ .
16 2 a polyethylene glycol 98.1 97.6 . (M~1 2,000) 17 2 a polyethylene ~lycol 87.3 9~-g monomethyl~ether (r~w 1,900)1 18 2 a - polyethylene glycol 93.3 96.7 dimethyl ether (r~W 400) 19 2 a polyethylene glycol 97~7 97.8 ~ 1 400) M~ = average molecular wei.ght :
- .
, ., lZ~04~;~
.~ ,, ~ 2/~ 197 COMPAR rlIVE EXArrDI,ES
A) Without catalyst and without dist1lling off the water which forms in the reaction (according to Gerrnan Offenlegungsschlif~ No. 2,640,730) 115 g (0O55 mol) ethyl-2-(4-hydroxyphenoxy) propanoate, 102 g (0.5 mol) 2~6-dichlorobellzothiazole and ~0.4 g (0.51 mol) potassium carbonate in 300 ml xylene are refluxed for 30 hours while st:irring well. The batch is cooled, freed from the sa]t, washed twice with 250 ml each of 5 % sodium hydroxide soiution and subsef;uently with water to neutralO After having distilled off the xylene, 65 o8 g of a brown oil are obtalned which according to gas chromatogr,lphy contains 91.1 % ethy1-2--/4-t6-chloro-2-benzothiazolyloxy)-phenoxy~-propanoa$e and 3.1 % of unreacted 2,6~dichlorobenzotniazole. This corresponds to a yield of 31.7 % only.
B) ~ithout catalyst~ but with distillation Or the - water formed in the reaction.
105.0 g (0.5 molj ethyl-2-~4-hydroxyphenoxy)-propanoate, 102.0 g (0.5 mol) 2,6-dlchlorobenzothiazole and 70.5 g (0.51 mol) potassium carbonate are introduced into 300 ml xylene and reflu~ed for 19 hours in a water separator under a nitrogen atmosphere. Subsequently~ the reaction mixture is cooled to room temperature, the salt portion is flltered off, the filtrate is washed with ~00 ml water, the organic phase is separated and concent~ated. Solvent residues are removed under highly reduced pressure. 162.3 g of a brown oll are o~talned which according to a gas chromatography analysis con-tains 93.6% ethyl-2-/4 (6~chloro-2--benzothiazolyloxy)-phenoxy/-propanoate and 6.4 ~ of unreacted 2,6-dichloro-benzothiazole. 'rhis corresponds to a yield of precisely 80 %.
~ C) In analogous manner as in Example 2b, with the use o~ the same start:~ng materia]s but with distil]ation of the ~later after a reaction time of about 3.5-4 hours, . , ' .
r ~ 4(~3 ~ 12 - H0~ 82/F 197 - 319.4 g (88.5 ~ of` theory) ethyl-2-/4-(6-chloro~2-benz~
oxazolyloxy)-phenoxy?~propanoate, m.p. 77-80.50C are obtained '.,he purity of which is 93.3 ~.
, , :
16 2 a polyethylene glycol 98.1 97.6 . (M~1 2,000) 17 2 a polyethylene ~lycol 87.3 9~-g monomethyl~ether (r~w 1,900)1 18 2 a - polyethylene glycol 93.3 96.7 dimethyl ether (r~W 400) 19 2 a polyethylene glycol 97~7 97.8 ~ 1 400) M~ = average molecular wei.ght :
- .
, ., lZ~04~;~
.~ ,, ~ 2/~ 197 COMPAR rlIVE EXArrDI,ES
A) Without catalyst and without dist1lling off the water which forms in the reaction (according to Gerrnan Offenlegungsschlif~ No. 2,640,730) 115 g (0O55 mol) ethyl-2-(4-hydroxyphenoxy) propanoate, 102 g (0.5 mol) 2~6-dichlorobellzothiazole and ~0.4 g (0.51 mol) potassium carbonate in 300 ml xylene are refluxed for 30 hours while st:irring well. The batch is cooled, freed from the sa]t, washed twice with 250 ml each of 5 % sodium hydroxide soiution and subsef;uently with water to neutralO After having distilled off the xylene, 65 o8 g of a brown oil are obtalned which according to gas chromatogr,lphy contains 91.1 % ethy1-2--/4-t6-chloro-2-benzothiazolyloxy)-phenoxy~-propanoa$e and 3.1 % of unreacted 2,6~dichlorobenzotniazole. This corresponds to a yield of 31.7 % only.
B) ~ithout catalyst~ but with distillation Or the - water formed in the reaction.
105.0 g (0.5 molj ethyl-2-~4-hydroxyphenoxy)-propanoate, 102.0 g (0.5 mol) 2,6-dlchlorobenzothiazole and 70.5 g (0.51 mol) potassium carbonate are introduced into 300 ml xylene and reflu~ed for 19 hours in a water separator under a nitrogen atmosphere. Subsequently~ the reaction mixture is cooled to room temperature, the salt portion is flltered off, the filtrate is washed with ~00 ml water, the organic phase is separated and concent~ated. Solvent residues are removed under highly reduced pressure. 162.3 g of a brown oll are o~talned which according to a gas chromatography analysis con-tains 93.6% ethyl-2-/4 (6~chloro-2--benzothiazolyloxy)-phenoxy/-propanoate and 6.4 ~ of unreacted 2,6-dichloro-benzothiazole. 'rhis corresponds to a yield of precisely 80 %.
~ C) In analogous manner as in Example 2b, with the use o~ the same start:~ng materia]s but with distil]ation of the ~later after a reaction time of about 3.5-4 hours, . , ' .
r ~ 4(~3 ~ 12 - H0~ 82/F 197 - 319.4 g (88.5 ~ of` theory) ethyl-2-/4-(6-chloro~2-benz~
oxazolyloxy)-phenoxy?~propanoate, m.p. 77-80.50C are obtained '.,he purity of which is 93.3 ~.
, , :
Claims (8)
1) A process for the preparation of compounds of the formula I
in which X is oxygen or sulfur R is halogen or CF3, and R1 is (C1-C12)alkyl optionally substituted by one or two halogen atoms or alkoxy, alkylthio, alkoxy-(C2-C4)-alkoxy each having from 1 to 6 carbon atoms, halo-(C1 or C2)alkoxy or methoxyethoxyethoxy; or is (C3-C6)alkenyl, (C3-C6)alkinyl, (C5 or C6)cycloalkyl, (C1-C4)alkoxycarbonyl-(C1 or C2)alkyl or the group -N=C?(C1-C4)alkyl?2, by reaction of compounds of with compounds of the formula II
II
with compounds of the formula III
III
in the presence of an inert non-polar solvent and an acid-binding agent, which comprise carrying out the reaction in the presence of a catalyst selected from the group of quaternary ammonium and phosphonium bases, polyalkylene glycols or their lower alkyl ethers.
in which X is oxygen or sulfur R is halogen or CF3, and R1 is (C1-C12)alkyl optionally substituted by one or two halogen atoms or alkoxy, alkylthio, alkoxy-(C2-C4)-alkoxy each having from 1 to 6 carbon atoms, halo-(C1 or C2)alkoxy or methoxyethoxyethoxy; or is (C3-C6)alkenyl, (C3-C6)alkinyl, (C5 or C6)cycloalkyl, (C1-C4)alkoxycarbonyl-(C1 or C2)alkyl or the group -N=C?(C1-C4)alkyl?2, by reaction of compounds of with compounds of the formula II
II
with compounds of the formula III
III
in the presence of an inert non-polar solvent and an acid-binding agent, which comprise carrying out the reaction in the presence of a catalyst selected from the group of quaternary ammonium and phosphonium bases, polyalkylene glycols or their lower alkyl ethers.
2) The process as claimed in Claim 1, which comprises using a quaternary ammonium or phosphonium halide as catalyst.
3) The process as claimed in Claim 1, which comprises using a polyethyleneglycol or polypropylene glycol or the lower alkyl ethers thereof having a molecular weight of 400 to 6,000 as catalysts.
4) The process as claimed in Claim 3, which comprises using a polyethyleneglycol or polypropylene glycol or the lower alkyl ethers thereof having a molecular weight of 1,000 to 3,000 as catalysts.
5) The process as claimed in Claims 1 to 3, wherein the amount of catalyst is from 0.05 to 1 mol% relative to component II.
6) The process as claimed in Claims 1 to 3, wherein the amount of catalyst is from 0.1 to 0.5 mol % relative to component II.
7) The process as claimed in Claims 1 to 3, wherein the reaction is carried out in the absence of water.
8) The process as claimed in Claim 1, wherein the water formed by thermal cleavage from the acid-binding agent is distilled off during the reaction either as an azeotropic mixture or under reduced pressure or with the aid of an inert gas current.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19823236730 DE3236730A1 (en) | 1982-10-04 | 1982-10-04 | METHOD FOR PRODUCING BENZOXAZOLYL AND BENZTHIAZOLYLOXYPHENOXYPROPION ACID DERIVATIVES |
DEP3236730.9 | 1982-10-04 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1210403A true CA1210403A (en) | 1986-08-26 |
Family
ID=6174908
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000438222A Expired CA1210403A (en) | 1982-10-04 | 1983-10-03 | Process for the preparation of benzoxazolyl- and benzothiazolyl-oxyphenoxypropionic acid derivatives |
Country Status (8)
Country | Link |
---|---|
EP (1) | EP0105494B1 (en) |
JP (1) | JPS5984877A (en) |
BR (1) | BR8305451A (en) |
CA (1) | CA1210403A (en) |
DE (2) | DE3236730A1 (en) |
HU (1) | HU189752B (en) |
IL (1) | IL69875A (en) |
ZA (1) | ZA837379B (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3561461D1 (en) * | 1984-03-14 | 1988-02-25 | Cassella Farbwerke Mainkur Ag | Process for the production of benzimidazolyl, benzoxazolyl and benzothiazolyl oxyphenoxypropionate derivatives |
US4935522A (en) * | 1988-03-21 | 1990-06-19 | Hoechst Celanese Corporation | Process for producing ethyl 2-[4'-(6"-chloro-2"-benzoxazolyloxy)phenoxy]propionate |
CA2479338A1 (en) | 2002-03-20 | 2003-10-02 | Metabolex, Inc. | Substituted phenylacetic acids |
US7199259B2 (en) | 2003-06-20 | 2007-04-03 | Metabolex, Inc. | Resolution of α-(phenoxy)phenylacetic acid derivatives |
KR20070036076A (en) | 2004-05-25 | 2007-04-02 | 메타볼렉스, 인코포레이티드 | Substituted triazoles as modulators of ppar and methods of their preparation |
US7714131B2 (en) | 2005-09-23 | 2010-05-11 | Metabolex, Inc. | Process for the stereoselective preparation of (−)-halofenate and derivatives thereof |
CN102351808B (en) * | 2011-09-06 | 2013-07-03 | 江苏中旗作物保护股份有限公司 | New method for synthesizing fenoxaprop-P-ethyl |
EP4209486A1 (en) | 2022-01-07 | 2023-07-12 | Adama Agan Ltd. | Process for the preparation of aryloxyphenoxypropionic acid derivatives in a non polar solvent with a tertiary amine catalyst |
CN114478425B (en) * | 2022-01-17 | 2024-03-22 | 安徽宁亿泰科技有限公司 | Synthetic method of aryloxy phenoxy propionate herbicide |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2640730C2 (en) * | 1976-09-10 | 1983-08-25 | Hoechst Ag, 6230 Frankfurt | Benzoxazolyloxy and benzothiazolyloxyphenoxy compounds and herbicidal agents containing them |
JPS5562043A (en) * | 1978-11-01 | 1980-05-10 | Ihara Chem Ind Co Ltd | Preparation of phenoxycarboxylic acid derivative |
ES8107193A1 (en) * | 1979-04-09 | 1981-10-16 | Hoechst Ag | Benzoxazolyloxy phenoxy esters and use as monocotyledonous weed grass herbicides |
-
1982
- 1982-10-04 DE DE19823236730 patent/DE3236730A1/en not_active Withdrawn
-
1983
- 1983-09-30 IL IL69875A patent/IL69875A/en not_active IP Right Cessation
- 1983-09-30 EP EP83109804A patent/EP0105494B1/en not_active Expired
- 1983-09-30 DE DE8383109804T patent/DE3377649D1/en not_active Expired
- 1983-10-03 BR BR8305451A patent/BR8305451A/en not_active IP Right Cessation
- 1983-10-03 ZA ZA837379A patent/ZA837379B/en unknown
- 1983-10-03 JP JP58183237A patent/JPS5984877A/en active Granted
- 1983-10-03 CA CA000438222A patent/CA1210403A/en not_active Expired
- 1983-10-03 HU HU833436A patent/HU189752B/en unknown
Also Published As
Publication number | Publication date |
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IL69875A (en) | 1987-09-16 |
IL69875A0 (en) | 1983-12-30 |
ZA837379B (en) | 1984-06-27 |
DE3377649D1 (en) | 1988-09-15 |
EP0105494B1 (en) | 1988-08-10 |
BR8305451A (en) | 1984-05-15 |
EP0105494A2 (en) | 1984-04-18 |
JPS5984877A (en) | 1984-05-16 |
HU189752B (en) | 1986-07-28 |
DE3236730A1 (en) | 1984-04-05 |
JPH051263B2 (en) | 1993-01-07 |
EP0105494A3 (en) | 1985-11-06 |
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