DE3211036A1 - Process for the preparation of alkenes - Google Patents

Abstract

The present invention relates to a process for the preparation of alkenes of the formula I <IMAGE> in which R<1>, R<2> and R<3> have the meaning given in the description, by reaction of alpha -hydroxyphosphonic acid esters of the formula II <IMAGE> in which R<1> and R<4> have the meaning given in the description, with phosphorus-containing olefination agents of the formula III <IMAGE> in which R<2> and R<3> have the abovementioned meanings and Z represents a phosphorus-containing radical <IMAGE> in which R<5> and R<6> are identical or different and individually represent alkyl, phenyl, alkoxy or phenoxy or together represent alkanedioxy, R<7> represents alkyl or phenyl and X represents halogen, in the presence of bases, if appropriate using diluents, at temperatures between -40 and 100 DEG C, which is characterised in that the reaction is carried out in the presence of sulphur.

Description

Process for the preparation of alkenes

The present invention relates to a new method of manufacture of alkenes.

It is already known that certain alkenes such as 3- (2-chloro-2-phenyl-vinyl) -2,2-dimethyl-cyclopropane-1 -carboxylic acid ethyl ester i obtained when s-hydroxymethane-phosphonic acid ester, such as e.g. α ((3-ethoxy-carbonyl-2,2-dimethyl-cycloprop-1-y1) -α-hydroxymethane-phosphonic acid diethyl ester, with phosphorus-containing olefinating agents such as diethyl α-chloro-benzylphosphonic acid , implements (see. DE-OS 2917 620).

However, this method has some disadvantages on an industrial scale on. Thus, the work-up to isolate the desired products requires the one as. Isomer mixtures obtained, a high technical effort. Also be they are only obtained in unsatisfactory yields.

The present invention relates to a process for the preparation of alkenes of the formula I. in which R1 represents an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aralkyl, aralkenyl or aryl radical or an optionally substituted heterocyclic radical, R2 represents hydrogen or halogen and R3 represents halogen, Cyano, for an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl, aralkenyl, aryl, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl or aminocarbonyl radical or for an optionally substituted heterocyclic radical, by reaction of »-Hydroxy-phosphonic acid esters of the formula II in which R1 has the meaning given above and R4 represents alkyl or phenyl or the two radicals R4 together represent straight-chain or branched alkanediyl (alkylene), with phosphorus-containing olefinating agents of the formula III in which R2 and R3 have the meanings given above and Z is a phosphorus-containing radical or or -P (R7) 3ffl X stands, where R5 and R6 are the same or different and individually stand for alkyl, phenyl, alkoxy or phenoxy or together stand for alkanedioxy, R7 stands for alkyl or phenyl and X stands for halogen, in the presence of Bases, if appropriate using diluents at temperatures between -40 and 100 ° C., which is characterized in that it is carried out in the presence of sulfur.

It can be described as extremely surprising that in the case of the invention Reaction conduct the use of sulfur very short reaction times with high conversions with high purity made possible.

The method according to the invention has a number of further advantages on. The high purity of the desired alkenes enables production technology simple work-up, the implementation is with short reaction times at room temperatures and cheap bases are to be used. The procedure can take place in one go lead directly to the corresponding carboxylic acid.

If OC (3-ethoxycarbonyl-2,2-dimethylcycloprop-1-yl) - <-hydroxy-methanephosphonic acid diethyl ester and d, 4-dichlorobenzylphosphonic acid diethyl ester are used as starting materials, the course of the reaction can be represented by the following reaction scheme: The process according to the invention for the preparation of alkenes of the formula (I) is preferably carried out using suitable solvents or diluents. In addition to water, practically all inert organic solvents can be used as such. These include in particular aliphatic and aromatic, optionally chlorinated hydrocarbons, such as pentane, hexane, heptane, cyclohexane, benzene, toluene, xylene, methylene chloride, ethylene chloride, chloroform, carbon tetrachloride, chlorobenzene and dichlorobenzenes, ethers, such as diethyl and dibutyl ethers, tetrahydrofuran and tetrahydrofuran Alcohols such as methanol, ethanol, n- and iso-propanol, n-, iso-, sec- and tert-butanol and aprotic polar solvents such as dimethylformamide and dimethyl sulfoxide.

To carry out the process according to the invention, sulfur is used in molar ratios of 1: 1 to 10: 1 are used, based on i-hydroxymethanephosphonic ester of the formula II. The ratio of 1.2: 1 to 2: 1 is preferably used.

When carrying out the process according to the invention, the bases are the bases customary in carbonyl olefinations are used. Alkali hydroxides are mentioned such as potassium and sodium hydroxide, alkali alcoholates such as potassium and sodium methylate, -äthylat, -n- and -iso-propylat, -n-, - iso-, -sec.-and -tert-butylat, alkali hydrides such as sodium hydride and alkyl lithium compounds such as butyl lithium.

The alkali metal hydroxides and / or alcoholates mentioned are preferred used.

The reaction is carried out at temperatures between -40 and 1000C, preferably between 10 and 500C.

The reaction is generally carried out under normal pressure.

When carrying out the process according to the invention, one sets up 1 mole of deso & hydroxymethanephosphonic ester formula (II) 1 to 2 moles of the phosphorus-containing Olefinating agent, of formula (III). The bases are generally used in 2 to 10 times the stoichiometric amount.

Place the base and sulfur in a suitable reaction medium and gives simultaneously or one after the other - if necessary in one of the specified Solvents dissolved - the starting materials of the formula (II) and III). To complete the reaction is stirred for a few hours.

Working up can be carried out by customary methods.

To isolate products that can be distilled, for example Distill off the solvent, the residue in a water-immiscible Take up solvents such as ligroin, wash the solution with water, dry it, filter and distill.

The reaction mixture can optionally be used to isolate crystalline products Pour into (ice) water and suck off the crystalline product, or you can Reaction mixture - if the solvent is not miscible with water - with water wash, dry, filter and evaporate. According to the last-mentioned work-up method Oily, difficult-to-distill products can also be obtained relatively pure.

The products are characterized by their melting or Boiling points.

Compounds to be prepared by the process according to the invention Formula (I) can be used as intermediates.

be used for the production of insecticides (compare DE-OS 2 738 150).

The hydroxyphosphonic acid esters to be used as starting materials are defined by formula (II).

Preferably are in it R4 for C1-C4-alkyl or for phenyl, or both radicals R4 together represent 2,2-dimethyl-propane-1,3-diyl, and R1 represents C1-C4-alkyl optionally substituted by fluorine or chlorine, for optionally by halogen, cyano, C1-C4-alkyl, C1-C4-alkylcarbonyl, C1-C4-alkoxycarbonyl and / or Phenoxybenzyloxy-carbonyl (which optionally by fluorine, cyano and / or Ethynyl is substituted) substituted C3-C6-cycloalkyl, for optionally by Benzyl or phenylethyl substituted with chlorine, or optionally by fluorine, Chlorine, bromine, C1-C4-alkyl and / or C1-C4-alkoxy substituted phenyl.

In a particularly preferred group of starting compounds of the formula (II), R1 in this formula is the radical where R 'stands for cyano, acetyl or C1-C4-alkoxycarbonyl and R4 stands for methyl or ethyl.

Examples are: oL- hydroxy-3-methyl-benzyl-, α- Hydroxy-4-methyl-benzyl-, α-hydroxy-3,4-dimethyl-benzyl-, «- hydroxy-4-fluoro-benzyl-, G- hydroxy-3-chlorobenzyl-, ct- hydroxy-4-chlorobenzyl-, - hydroxy-3,4; -dichlorobenzyl-, - Hydroxy-3-bromo-benzyl-, α-hydroxy-4-bromo-benzyl-, α- - hydroxy-4-methoxy-benzyl and α-hydroxy-3,4-dimethoxy-benzylphosphonic acid dimethyl ester and diethyl ester; α-Hydroxy-α- (3-methoxycarbonyl-2,2-dimethyl-cycloprop-1-z1) -methaphosphonic acid dimethyl ester and diethyl ester, d-hydroxy <- (3-ethoxycarbonyl-2,2-dimethylcycloprop-1-yl) methanephosphonic acid dimethyl ester and diethyl ester, cL-hydroxy-d- (3-acetyl-2, 2-dimethylcycloprop-1-yl) -methanephosphonic acid dimethyl ester and diethyl ester as well as α-hydroxy-α- (3-cyano-2,2-dimethylcycloprop-1-Y1) -methaphosphonic acid dimethyl ester and diethyl ester.

The phosphorus-containing olefinating agents to be used as starting materials are defined by formula (III). Preferably, R2 is hydrogen, chlorine and bron, R3 is phenyl, which is optionally substituted by halogen, C1-C4-alkyl, C1-C2-haloalkyl, C1-C4-alkoxy, C1-C2-haloalkoxy, C1-C2- (halo ) Alkylenedioxy, C1-C4-alkyl-thio and / or C1-C2-haloalkylthio is substituted, and Z preferably represents the remainder where R ″ and Rv are identical or different and individually stand for C1-C4-alkoxy, phenoxy or together for 2,2-dimethyl-propane-1,3-dioxy.

Examples include: dimethyl benzylphosphonate and -diethyl ester, α-chlorobenzylphosphonic acid dimethyl ester and diethyl ester, α-Bromo-benylphosphonic acid dimethyl ester and diethyl ester, 4-fluorine, 3-chlorine, 4-chloro, 3,4-dichloro, 3-bromo, 4-bromo, 3-methyl-, 4-methyl-, 3,4-dimethyl-, 4-methoxy- and 3,4-dimethoxy-benzylphosphonic acid dimethyl ester and diethyl ester; 4-fluorine, 4-chloro, 3-chloro, 3,4-dichloro, 3-bromine, 4-bromo, 3-methyl, 4-methyl, 3,4-dimethyl, 4-methoxy- and 3,4-dimethoxy-Os-chlorobenzylphosphonic acid dimethyl ester and diethyl ester; 4-fluorine, 3-chlorine, 4-chlorine, 3,4-dichloro, 3-bromine, 4-bromine, 3-methyl-, 4-methyl-, 3,4-dimethyl-, 4-methoxy- and 3,4-dimethoxy-α-bromo-benzylphosphonic acid dimethyl ester and diethyl ester.

According to a particular embodiment, resulting in the reaction mixture Carboxylic acid esters as easy-to-isolate carboxylic acids by adding water can be obtained in high purity.

example 1 216 g (4 mol) of sodium methylate in 600 g of methanol and 46 g (1.5 mol) of sulfur are initially introduced.

A mixture of 312 g (1.05 Mol) i, 4-dichlorobenzylphosphonic acid diethyl ester and 308 g (1.0 mol) OC-hydroxy-oC (3-ethoxy-carbonyl-2,2-dimethyl-cyclopro-1-y1) -methanephosphonic acid diethyl ester.

After 3 hours of stirring at 30 ° C., 100 g of water are added and methanol is distilled off at normal pressure. Little by little it becomes 1,200 g of water add, then adjusted to pH 9 with hydrochloric acid and extracted with toluene.

The pH is then adjusted to 6 with hydrochloric acid and the mixture is extracted with toluene and washed with water and toluene is distilled off.

261 g (91.6% of theory) of 3- (2-chloro-2- (4-chlorophenyl) vinyl) -2,2-dimethyl-cyclopropane-1-carboxylic acid are obtained of melting point 1180C.

Example 2 A mixture of 30 g (0.1 mol) of diethyl α, 4-dichlorobenzylphosphonate and 6 g (0.19 mol) of sulfur is added dropwise to a mixture of 45 g (0.4 mol) of 50% potassium hydroxide solution and 6 g (0.19 mol) of sulfur 28 g (0.1 mol) of oC-hydroxy-4-chlorobenzyl phosphonic acid diethyl ester, dissolved in 20 ml of methanol. The mixture is stirred for a further 3 hours at 30.degree.-350.degree. C., the product is taken up in 150 ml of toluene, and the org. Phase twice with water and toluene is distilled off. The residue crystallizes out. 24 g (85% of theory) of 1-chloro-1- (4-chlorophenyl) -2- (4-chlorophenyl) -ethene with a melting point of 890 ° C. are obtained.

Example 3 To a mixture of 32.5 g (0.6 mol) of sodium methylate in 100 ml of methanol and 5 g (0.15 mol) of sulfur is added dropwise a mixture of 30 g (0.1 mol) i, 4- Dichlorobenzyl-phosphonic acid diethyl ester and 22 g (0.1 mol) of i-hydroxy - # - methyl-prop-2-en-phosphonic acid diethyl ester, stirred for 2 hours at 25-300 ° C., methanol is distilled off, poured into water and extracted with 150 ml of toluene. The toluene phase is washed twice with water, toluene is distilled off and the residue is recrystallized from ligroin.

16 g (70% of theory) of 1-chloro-1- (4-chlorophenyl) -4-methyl-butadiene are obtained of melting point 490C.

Claims (1)

Process for the preparation of alkenes of the formula I. in which R1 represents an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aralkyl, aralkenyl or aryl radical or an optionally substituted heterocyclic radical, R2 represents hydrogen or halogen and R3 represents halogen , Cyano, represents an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl, aralkenyl, aryl, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl or aminocarbonyl radical or represents an optionally substituted heterocyclic radical Implementation of C6-hydroxy-phosphonic acid esters of the formula in which R1 has the meaning given above and R4 stands for alkyl or phenyl or the two 4 radicals R together stand for straight-chain or branched alkanediyl (alkylene), with phosphorus-containing olefinating agents of the formula III in which R2 and R3 have the meanings given above and Z is a phosphorus-containing radical or - (R7) 3+ X-, where R5 and R6 are identical or different and individually represent alkyl, phenyl, alkoxy or phenoxy or together represent alkanedioxy, R7 represents alkyl or phenyl and X represents halogen, in the presence of Bases, if appropriate using diluents at temperatures between -40 and 100 ° C., which is characterized in that it is carried out in the presence of sulfur.