MXPA00002343A - Method for preparing 1-phenylpyrrazolin-3-carboxylic acid derivatives - Google Patents

Abstract

The present invention relates to a method for preparing 1-phenylpyrrazolin-3-carboxylic acid derivatives of the general formula (III), wherein said method comprises reacting hydrazones of the general formula (I) with olefins of the general formula (II) using a base as a catalyst. In the above-mentioned formulae, Ph is an optionally substituted phenyl, R1 is hydrogen or alkyl, R2 and R3 are independently hydrogen, halogen, cyano, an optionally substituted organic residue or R2 and R3 form together with the carbon atom bearing them a saturated or partially saturated cyclic compound comprising 5 or 6 atoms. X is amino, hydroxy, alkoxy, cycloalkoxy, alkylamino, dialkylamino, alkyloxyalkyloxy, trialkylsilyloxy or trialkylsilylmethyloxy and Y is chlorine or bromine. This reaction is carried out in a two-phase system comprising an organic phase and an aqueous phase using a sterically hindered amine and an optional other base. The 1-phenylpyrrazolin-3-carboxylic acid derivatives of the present invention can be used as phyto-protective agents, i.e. as agents for protecting useful crops in agriculture or silviculture against undesired effects due to the application of herbicides.

Description

METHOD FOR PREPARING ACID DERIVATIVES 1- PHENYLPIRAZZOLINE-3-CARBOXYLIC DESCRIPTIVE MEMORY The present invention relates to a process for preparing 1-phenylpyrazoline-3-carboxylic acid derivatives by means of a cycloaddition by basic catalysis of 2-phenylhydrazone compounds with substituted olefins in a two-phase system. The pyrazolines, like five other types of heterocyclic compounds, can be prepared, for example, by means of cycloaddition [3 + 2] of unsaturated compounds with 1,3-dipolar molecules; see, for example, Jerry March "Advanced Organic Chemistry", 3rd Ed., John Wiley & Sons, N.Y. 1985, pages 743-745, and the cited literature. Since a large number of 1, 3-dipolar molecules are often not storage stable, it is convenient to use instead those compounds that react in situ with 1,3-dipolar molecules when exposed to bases. These reactions are usually carried out in the presence of a base with or without solvents. WO 91/07874 has described some 1-phenylpyrazoline-3-carboxylic esters as compounds that protect plants useful in agricultural and forestry crops against undesirable damage associated with the effect of the herbicides. The synthesis described there of 1-phenylpyrazoline-3-carboxylic esters ___ f ___ i _ ?? _____ - "- ** - ---- is carried out in such a way that the 2-phenylhydrazones of haloglyoxal esters react with substituted olefins with basic catalysis, however, this procedure implies some disadvantages: a) insufficient yield, 5 b) insufficient purity of the product, c) high consumption of the tertiary amines used as a base, d) complicated elimination of the salt formed during the reaction of the hydrogen haiogenide and the tertiary amine, e) high amount of waste in the product of 2-10 phenylhydrazone toxicologically unacceptable and unreacted, f) risk of polymerization of olefins under the prevailing basic conditions.Therefore, an object of the present invention is to provide a process that allows the economic preparation of acid derivatives. 1-Phenylpyrazoline-3-carboxylic acid in high purity This objective is carried out with bases in the known procedure for the preparation of drift two of 1-phenylpyrazoline-2-carboxylic acid of the formula III by means of a reaction of hydrazones of the formula I by basic catalysis, with olefins of the formula II. ((ll) (lll) wherein, Ph is optionally substituted phenyl, R1 is hydrogen or alkyl, R2 and R3 independently of one another are hydrogen, halogen, cyano, an optionally substituted organic radical, or R2 and R3 together with the carbon atom to which they are attached form a saturated or partially saturated ring of 5 or 6 atoms, X is an amino, hydroxyl, alkoxy, cycloalkoxy, alkylamino, dialkylamino, alkyloxyalkyloxy, trialkylsilyloxy, or trialkylsilylmethyloxy group and Y is chloro or bromo. The process according to the invention consists in carrying out the reaction in a two-phase system in the presence of a sterically hindered amine and, if appropriate, another base. For the present process it is preferred to use the aforementioned compounds wherein Ph, R1 and Y are as defined above and R2 and R3 independently of one another are hydrogen, halogen, cyano, C.sub.6-alkyl, cycloalkyl of C3-C6, C2-C6 alkenyl, C2-C6 alkynyl, d-Cß haloalkyl, C-Cß alkoxy Ci-Cß alkyl, C-C6 alkylcarbonyl, C-Cβ alkoxycarbonyl , C 1 -C 6 alkylaminocarbonyl, C 1 -C 7 dialkylaminocarbonyl, phenyl which is unsubstituted or substituted by one or more identical or different radicals selected from the group consisting of amino, carboxyl, cyano, formyl, halogen, hydroxyl, nitro, ^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^ alkyl of C.-C4, alkoxy of C-1-C4, alkylcarbonyl of C.-C, alkoxycarbonyl of C.-C, C 1 -C 4 halogenoalkyl, C.sub.1 -C halogenalkoxy, C.sub.C alkylthio and C.sub.1 -C.sub.4 alkylsulfonyl, or R.sub.2 and R.sub.3 together with the carbon atom to which they are attached form a saturated ring of 5 or 6 atoms , 5 and X is an amino, hydroxyl, alkoxy group of C.-Cβ, C3-Cβ cycloalkoxy, C? -C6 alkylamino, dialkylamino of C.-Cß, C-C6 alkyloxy-C1alkyloxy. -Ce, trialkylsilyloxy of C.-Ce and tri-silylmethyloxy of C.-Ce- The term "halogen" includes fluorine, chlorine, bromine and iodine. An optionally substituted organic radical is phenyl or alkyl, alkenyl, alkynyl, cycloalkyl, alkoxyalkyl, alkylcarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, each of which has more than 10 carbon atoms in the corresponding hydrocarbon radical, and each of which is unsubstituted or substituted by one or more atoms of identical or different halogens. By "Ci-Cß alkyl" is meant a branched or unbranched hydrocarbon containing one, two, three, four, five or six carbon atoms, for example methyl, ethyl, propyl, 1-methylethylene, butyl, 1-methylpropyl , 2-methylpropyl, 1,1-dimethylethylene, pentyl, 2-methylbutyl, 1,1-dimethylpropyl, and hexyl. By the combined terms such as "C.sub.6 -C.alkoxy", "CrC.sub.6 alkylamino" and "C.sub.Cß trisyloxy" is meant an alkoxy, alkylamino or silyloxy group whose alkyl radicals have the corresponding meaning in sw gtfefe i Sg | beginning to the term "C-Cß alkyl". "Dialkylamino of C-CT" means that the two alkyl radicals can be identical or different. C3-C8 cycloalkyl is cyclopropyloxy, cyclobutyloxy, cyclopentinyloxy, cyclohexyloxy, cycloheptyloxy and cyclooctyloxy. The terms "alkenyl" and "alkynyl" mean that the carbon chain may be branched or unbranched and contains at least one multiple bond, it being possible for the latter to be located at any position of the unsaturated radical in question. An "optionally substituted phenyl" means that one or more hydrogen atoms of the phenyl radical are replaced by identical or different substituents, selected from the group consisting of amino, carboxyl, cyano, formyl, halogen, hiroxyl, nitro, C-C4 alkyl) C 1 -C 4 alkoxy, C 1 -C 4 alkylcarbonyl, C 1 -C 4 alkoxycarbonyl, C 1 -C 4 haloalkyl, C 4 -Chaloalkoxy, C 4 -C 4 alkylthio, and C 1 -C 4 alkylsulfonyl. .-C4. "Halogenoalkoxy" and "halogenoalkyl" mean that one or more hydrogen atoms are replaced by the corresponding number of identical or different halogens. A ring having 5 or 6 atoms represents a carbocyclic or heterocyclic radical in which up to 2 ring atoms can come from the group consisting of nitrogen, oxygen or sulfur, it being possible for this ring to be saturated or partially saturated and optionally substituted by 1. or 2 methyl groups, for example, cyclopentyl, cyclohexyl, cyclohexenyl and 3-oxacyclopentyl.

In the process according to the invention, phase one (organic phase) comprises, at the beginning of the reaction, hydrazone (also called component I in the lower part), olefin (also called component II in the lower part) and if appropriate, organic solvents, while the second phase comprises water (aqueous phase). Depending on the solubility, the sterically hindered amine is dissolved in the organic phase and / or in the aqueous phase, while the other base is, as a rule, virtually completely dissolved or suspended in the aqueous phase. As the reaction progresses, the amount of components I and II in the organic phase decreases, while the amount of compound of the formula III increases.

As the amount of base in the aqueous phase decreases during the progress of the reaction, the amount of salt formed by the hydrogen haiogenide that originates during the reaction and the base increases in this phase. Suitable solvents, in principle, are all inert organic solvents under the reaction conditions of the process according to the invention, for example, those which do not produce undesired reactions. Especially suitable solvents are those containing aliphatic, cylcoaliphatic, unsaturated and aromatic aliphatic hydrocarbons, which may be chlorinated in each case, such as hexane, ligroin, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene, methylene chloride, chloroform, carbon tetrachloride, ethylene chloride and trichlorethylene, aliphatic ketones such as ketones, methyl ethyl ketones, methyl isopropyl ketones, and methyl isobutyl ketones, carboxylic esters such as ethyl acetate and l ___ lti_ta _____ M ___ ll_É ______ Í__J amyl, carboxamides, such as N-methylpyrrolidone, dimethylformamide, and dimethylacetamide, carbonitriles such as acetonitriles and propionitriles, sulfoxides such as dimethyl sulfoxide and also sulphones such as sulfolane. Naturally, a mixture of these can also be used. Similarly, the process can be carried out without organic solvents. The molar ratio between component II and component I can be selected within a range that is generally from 1 to 20, preferably from 1 to 10, especially preferably from 1 to 5. If the process according to the invention is carried Without solvents, a larger amount of component II should preferably be selected. In this case, the molar ratio between component II and component I is preferably from 2 to 20, especially from 2 to 10. Also, a preferable advantage of the method according to the invention is that in the present case, the excess of component II together with the amine with Steric hindrance can be distilled after the end of the reaction and reused in a new batch of reaction. All sterically hindered amines capable of binding the hydrogen halide released during the reaction are suitable for the process according to the invention. They are especially Suitable amines of the group of dialkylamines, such as diisopropylamine, trialkylamines, such as triethylamine and tributylamine, dialkylbenzylamines such as N, N-dimethylbenzylamine, alkyldibenzylamine, and aromatic amines such as pyridines. They can be used in quantities catalytic as a catalyst or at least in stoichiometric amounts. Normally, they are used in a molar ratio of 0.001 to 2, preferably 0.01 to 2, especially preferably 0.01 to 0.1, based on component I. If amines with stoichiometric impairment are used, in a catalytic amount, that is, amount substoichiometric, the additional use of another base is necessary. For this purpose, those bases which are equally capable of binding the hydrogen haiogenide released during the reaction are suitable. Particularly suitable are bases consisting of alkali metal carbonates and alkaline earth metal carbonates such as lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, and calcium carbonate, alkali metal bicarbonates and alkaline earth metal bicarbonates such as sodium bicarbonate. sodium, potassium bicarbonate, magnesium bicarbonate and calcium bicarbonate, alkali metal hydroxides, and alkaline earth metal hydroxides, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide, alkali metal acetates such as sodium acetate, alkali metal alkoxy, such as sodium methoxide, sodium ethoxide, potassium terbutoxide. Normally, these are used in a molar ratio of 0 to 200, preferably from 0 to 100, and especially preferably from 10 to 100, based on the sterically hindered amine. To obtain optimum performance, the total amount of base, that is, the amount of sterically hindered amine and additional base, must be chosen to be large enough to completely bind to the hydrogen haiogenide formed during the reaction by means of the base. The amount of water required to carry out the process according to the invention, must be selected within a wide range. It must be large enough to accommodate the salts formed during the reaction of the hydrogen halide, the sterically hindered amine and the additional base. The molar ratio between water and component II is usually in a range of 2 to 100, preferably 2 to 50. Here, the given molar ratio is based on the total amount of water used, i.e., the amount of water introduced. at the beginning of the reaction and the amount of water, which contains the additional base, which if appropriate, is added dropwise in the course of the reaction. A special advantage of the process according to the invention is also the fact that the sterically hindered amine, which is relatively expensive, must be used only in catalytic amounts and is continuously regenerated by the additional base, which is relatively inexpensive. Naturally, additives, such as polyethylene glycols, quaternary ammonium salts, and crown ethers, should be added, for example to increase the solubility of the bases. These additives are known to those skilled in the art. The preparation of components I is described, for example, in WO91 / 07874. As a rule, components II are commercially available or can be prepared by methods known to those skilled in the art. The process, according to the invention, is usually carried out in such a way that the components I and II, the sterically hindered amine, the water, and if appropriate, the organic solvent are introduced into a reaction vessel. . If the sterically hindered amine is not used in catalytic amounts, but in stoichiometric amounts, no more base is added, and the reaction mixture is brought to the required reaction temperature and stirred at this temperature. The The reaction temperature depends essentially on the reactivity of the components I and II used. It is usually between 0 and 150 ° C, preferably between 20 and 120 ° C. The process can be carried out at atmospheric pressure or under reduced pressure. If a solvent is used, care must be taken if its boiling point is at least as high as the reaction temperature required. In addition, care must be taken, especially in the case of the phase-mediating solvent, such as dimethylformamide, acetone and methanol in which the two-phase system of the reaction mixture is maintained. If the sterically hindered amine is to be used in catalytic quantities, an additional base, which is convenient When it is dissolved in a suitable solvent, it is added to the reaction mixture at the required reaction temperatures in such a way that the pH of the aqueous phase of the reaction mixture is in a range between 6 and 9. adequate solvent depends, essentially, on the nature of ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^ HS ^^ wc ^^^ g the base used. In this way, for example, water can be used for bases such as potassium carbonate and sodium hydroxide, while in the case of alkoxy it is convenient to use the alcohol on which this base is based, for example, methanol in the case of sodium methoxide. For example, the pH must be continuously checked by means of a potentiometer immersed in the reaction mixture, or discontinuously by sampling in brief intervals of time. The reaction, which can take approximately 2 to 48 hours and can be monitored, for example, by thin layer chromatography, is preferably carried out until the reaction of component I is complete. The treatment of the reaction mixture must be carried out by methods generally known as distillation, extraction and / or filtration. The method of treatment depends on the properties of the reaction mixture. As a rule, the reaction mixture can first be liberated from all volatile components, such as solvents, water, hindered amines and excesses of component II by means of distillation. An advantage of the process, according to the invention, is that this distillate, which comprises the amines and the component II, can be used in another reaction batch. For further purification, the crude product can be extracted from the distillation residue by means of a solvent, and after the solvent has been removed, it is purified by chromatography, distillation or crystallization. *** > * a «^,. -.- .. t._. »_ ^.« G.- .. * ^ _. , .-., J, -J- .- »_----. ._ < _________ i_aiatJi ^^^ __ ^ - ^ Ma¿ ^ -. * _- > ^ ._.. - _-_ »_» - ..

As a rule, the compounds with formula I are obtained with higher yields and purity, by the process according to the invention than those obtained with the prior art. In addition, the content of the toxicologically unacceptable hydrazone of the formula I is notably lower. In addition, less amine is required. The following comparative example demonstrates the advantages of the method according to the invention over the aforementioned one.

EXAMPLE Preparation of diethyl 1- (2-4-dichlorophenyl) -5-methyl-2-pyrazolino-3,5-dicarboxylate (la) (lia) (Illa) 598.2 g (2 moles) of ethyl 2-chloro- (2,4-dichlorophenylhydrazono) carboxylate ethyl ester (la), 456 g (4 moles) of ethyl methacrylate (lia) and 10.1 g ( 0.1 moles) of triethylamine together with 100 ml of water are introduced into a shaking flask. A solution of 195 g (1.95 mol) of potassium hydrogen carbonate is added dropwise in 600 ml of water at a temperature of 60 to 65 ° C over the course of two hours so that the pH of the aqueous phase of the mix of reaction does not exceed the value of 8. After the dropwise addition is complete, stirring is continued for 20 minutes at the above-mentioned temperature. The excess ethyl methacrylate is distilled in vacuo with water and triethylamine. The reaction residue is extracted with toluene. The resulting toluene extract is freed of solvents and subsequently distilled in a medium to high vacuum. This gives 754.2 g (98% in theory) of diethyl 1- (2-4-dichlorophenyl) -5-methyl-2-pyrazoline-3,5-dicarboxylate (Illa) with a melting point of 42-44 ° C and 97% purity (determined by CLAR).

^^^^ A ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ggggggg ^ g ^^^^^^^^ ^^^^ The following table shows the reaction parameters and relevant analytical data of the process according to the invention (experiment A) compared to the prior art (experiment B).

PICTURE 1) Solid with melting point of 42 to 44 ° C 2) Oil with refractive index nD20 = 1.5651 3 > Out of detection limit. ^ ¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ .-..- - • gr.a.: ..... to ^ t;

Claims (3)

NOVELTY OF THE INVENTION CLAIMS 5 1.- A procedure for the preparation of acid derivatives

1-phenylpyrazoline-3-carboxylic acid of the formula III by means of a reaction by basic catalysis of hydrazones of the formula I with olefins of the formula II (i) (ll) (NI) where Ph is an optionally substituted phenyl, R1 is a hydrogen or an alkyl, R2 and R3 independently of one another are hydrogen, halogen, 15 cyano, an optionally substituted organic radical, or R2 and R3 together with the carbon atom to which they are attached to form a saturated or partially saturated ring of 5 or 6 atoms, X is an amino, hydroxyl, alkoxy, cycloalkoxy, alkylamino group, dialkylamino, alkyloxyalkyloxy, trialkylsilyloxy, or trialkylsilylmethyloxy and Y is a chlorine or bromine, which comprises carrying out The reaction in a two phase system in the presence of a sterically hindered amine and, if appropriate, another base. 2. The process according to claim 1, further characterized in that the first phase comprises hydrazone, olefin and, if convenient, at least one organic solvent and the other phase comprises water. 3. The process according to claim 1 or 2, further characterized in that the sterically hindered amine is 5 selected from a group consisting of dialkylamines, trialkylamines, dialkylbenzylamines, alkyldibenzylamines, aromatic amines, and the additional base is selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates, alkali metal bicarbonates, alkaline earth metal bicarbonates, hydroxides of alkali metal, alkaline earth metal hydroxides, alkali metal acetates and alkali metal alkoxy. 4. The process according to any of claims 1 to 3, further characterized in that the reaction is carried out without solvent. 5.- The procedure in accordance with any of the 15 claims 1 to 4, further characterized in that the additional base is dosed in such a way that the pH of the aqueous phase of the two-phase system is within a range between 6 and 9 at the beginning, during and at the end of the reaction. 6. The process according to any of claims 1 to 5, further characterized in that the reaction is carried out under atmospheric pressure or reduced pressure and at a temperature between 25 and 120 ° C. 7. The process according to any of claims 1 to 6, further characterized in that R 2 and R 3 independently of one another are hydrogen, halogen, cyano, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl, C

2 -C 6 alkenyl, C2-C6 alkynyl, halogenalkyl of C.-Cd, alkoxy of C.-Cß-alkyl of C -? - C6, alkylcarbonyl of C.-Cß, alkoxycarbonyl of Ci-Cß, alkylaminocarbonyl of Ci-Cß, dialkylaminocarbonyl of C.-Cß, phenyl which is unsubstituted or substituted by one or more identical or different radicals selected from the group consisting of amino, carboxyl, cyano, formyl, halogen, hydroxyl, nitro, C 1 -C 4 alkyl, C 1 -C 4 alkoxy, C 1 -C 4 alkylcarbonyl, C 1 -C 4 alkoxycarbonyl, C 1 -C 4 haloalkyl, C 1 -C 4 halogenoalkoxy, C 1 -C 4 alkyloxy C.-C and C 1 -C 4 alkylsulfonyl, or R 2 and R 3 together with the carbon atom to which they are attached form a saturated ring of 5 or 6 atoms, and X is an amino, hydroxyl, alkoxy group of C. -Cß, C

3-C8 cycloalkoxy, alkylamino of C.-C6, C-C6 dialkylamino, C-C6-alkyloxy-C.sub.1 -C.sub.1, trialkylsilyloxy of C.-C6 and tri-silylmethyloxy of C.-Ce. 8. The process according to any of claims 1 to 7, further characterized in that the molar ratio between the sterically hindered amine and the hydrazone is 0.01 to 2 and the ratio 20 molar between the additional base and the sterically hindered amine is from 0 to 100. 9. The process according to claim 8, further characterized in that the molar ratio between the amine with steric hindrance and the hydrazone is from 0.01 to 0.1 and the molar ratio between the additional base and the sterically hindered amine is from 10 to 100. 10. The process according to any of claims 1 to 9, further characterized in that the molar ratio between the olefin and the hydrazone is from 1 to 10. 11. The process according to claim 10, further characterized in that the molar ratio between the olefin and the hydrazone is from 1 to 5. 12. The process according to any of claims 1 to 11, further characterized in that the molar ratio between the water and the olefin is from 2 to 50. The present invention relates to a method for preparing 1-phenylpyrazoline-3-carboxylic acid derivatives of the general formula III, said method consists in reacting hydrazones of the general formula I with olefins of the general formula II, using a base such as catalyst (l) (ll) (N in the above-mentioned formulas, Ph is an optionally substituted phenyl, R1 is a hydrogen or an alkyl group, R2 and R3 are independently hydrogen, halogen, cyano, an optionally substituted organic residue or R2 and R3 form together with the carbon atom to which they are attached, a saturated or partially saturated cyclic compound containing 5 or 6 atoms, X is an amino, hydroxyl, alkoxy, cycloalkoxy, alkylamino, dialkylamino, alkyloxyalkyloxy, trialkylsilyloxy or trialkylsilylmethyloxy group and Y is chlorine or bromine, this reaction is carried out in a two-phase system comprising an organic phase and an aqueous phase using a hindered amine and optionally another base, the 1-phenylpyrazoline-3-carboxylic acid derivatives of the present invention can be used as phytoprotective agents, that is, as crop protection agents, useful in agriculture or forestry against undesirable effects due to the application of herbicides. EP / mmr * P00 / 163F