DE2732456A1 - METHOD FOR MANUFACTURING CHRYSANTHEMIC ACID ESTERS AND HOMOLOGOUS THEREOF - Google Patents

Description

DR. A. VAN DERWERTH

DlPt-ING. (1934-1974)

PATF NTA N WA LTE DR. FRANZ LEDERER

DlPL-CHEM.

RElNERF. MEYER

DIPL.-ING.

A / S Cheminova Lemvig / Denmark

8000 MUNICH 80 LUqiLE-GRAHN-STRASSE 22

TELEPHONE: (089) 472947 TELEX: 524624 LEOER 0 TELEGR .: LEATHER PATENT

July 18, 1977 7736A

Process for the preparation of chrysanthemic acid esters and

Homologues of these

The invention relates to a process for the preparation of chrysanthemic acid esters and their homologues. In particular, the invention relates to a process for the preparation of chrysanthemic acid esters and their homologues following formula:

C = CH-CH - CH-COOH,

R ₁ 'C

R. J

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wherein R ,. and R ~, which can be the same or different Hydrogen atom or an alkyl group having 1 to 6 carbon atoms and preferably the methyl group, R, and R ^, which may be the same or different, are an alkyl group with 1 to 6 carbon atoms, preferably a methyl group, or a halogen atom, preferably a fluorine, chlorine or Are bromine atoms, or together with the carbon atom to which they are attached, a cycloalkylidene group with up to to form 8 carbon atoms, and

Rc is an alkyl group having 1 to 6 carbon atoms and preferably is an ethyl or propyl group.

The compounds of the formula I are valuable intermediates for the preparation of synthetic pyrethroids with insecticidal properties of the type described, for example, in Nature, 246 , 11/16/1973, pages 169/170.

The invention relates to an improved process for the preparation of chrysanthemic acid esters and homologues and analogs thereof of the formula I, the process according to the invention having significant improvements over previously known methods of operation the starting material and the process economy on v / ei st.

The process according to the invention is characterized in that (1) an epoxide of the following formula

C-CH ₀ -CH-C II

** ^Xl ° ^R 2

wherein X ^ is a halogen atom and preferably a chlorine or Is bromine atom, and R ^, Rp, R, and R ^, those given above Have meanings with a malonic acid ester of the following formula:

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III

wherein Rg is an alkyl group having 1 to 6 carbon atoms and is preferably an ethyl or methyl group, in Presence of one equivalent of a base to form a compound of the following formula:

_{R / i} - C-CH ₂ -CH - CH-COOR ₆ / RC C = O

^x i V \ /

^R 2 °

is implemented,

(2) the lactone of formula IV in the presence of an inert solvent to effect removal of the carbalkoxy group and to obtain a lactone represented by the following formula

R, - C-CH ₀ -CH - ClI

"/ R ₁ -CC = O

^x i V \ s

^R 2

is heated,

(3) the lactone of the formula V with a chlorinating or hydrochlorinating agent and with an aliphatic alcohol RcOH, in which R ₁ - has the meaning given above, to bring about ring splitting, chlorination and esterification with the formation of a compound of the following formula:

709884/0946

- C-CH-CH-CH _o -C00R_

'VI

χ ^R i " ^c v
^χ ι V \

R ₂ Cl

is implemented,

the ester of formula VI with two equivalents of a base to induce elimination of hydrogen chloride and an internal condensation to form the desired product of formula I is treated.

The individual stages of the process according to the invention are explained in greater detail below.

Step (1), the condensation between the epoxide of formula II and the malonic acid ester of formula III, is in the presence carried out from one equivalent of base. Any suitable organic or inorganic base can be used for this purpose are, preferably sodium ethoxide and / or methoxide. The reaction is preferably in the presence of an inert Solvent carried out. The choice of solvent is not critical and either polar or non-polar, protic or aprotic solvents can be used, preferably ethanol and methanol.

The step (2), the removal of the carbalkoxy group from the lactone of the formula IV is carried out at elevated temperature, preferably from 100 ⁰ C to 200 ⁰ C, and in the presence of an inert solvent. Any organic or aprotic solvent can be used. Preferred solvents are: dimethyl sulfoxide (DMSO), dimethylformamide (DMF), hexamethylphosphoric triamide (ΗΜΓΑ), N-methyl-2-pyrrolidone (NMF), methanol, water and mixtures of two or more of these solvents. Mixtures of methanol and Wapser are particularly preferred. The reaction can be carried out with or without a KstaIyKator

709884/0946

be carried out, catalysts are z. B. an alkali metal halide or quaternary ammonium halide, preferably sodium bromide, potassium chloride or tetraethylammonium bromide. In general, however, it is preferred not to use a catalyst in step (2).

Stage (3) is advantageously carried out at an elevated temperature, preferably from 50 ^° C. to 150 ^° C., and in the presence of a catalyst. Suitable catalysts are Lewis acids, e.g. B. FeCl ₅ , NiClp, BF, and ZnClp, of which FeCl is preferred. Suitable chlorinating or hydrochlorinating agents are e.g. E.g .: SOCl ₂ , HCl, PCI ,, PCIc, POCl ₅ , COCl ₂ and CSCl ₂ .

The stages (i) the ring cleavage and the chlorination and (ii) the esterification can be carried out simultaneously, ie in a single reaction mixture which contains the lactone V, the chlorinating or hydrochlorinating agent, the alcohol R ₁ -OH and, preferably, the catalyst contains, or in stages, ie the lactone V is reacted first with the chlorinating or hydrochlorinating agent, preferably in the presence of the catalyst, and then with the alcohol Rj-OH. In the latter case, ie in the case of the step-wise implementation, it is preferred not to isolate the intermediate product, but to add the alcohol Rc-OH to the reaction mixture when the ring cleavage and the chlorination have been completed.

It is preferred to carry out the steps (i) and (ii) described above simultaneously using a reaction mixture which contains SOCl ₂ as the chlorinating agent, ethyl or propyl alcohol as the alcohol, R ₅ OH and FeCl _{5 as the catalyst.} It is also preferred to carry out these reactions under superatmospheric pressure, suitable pressures depending on the equipment used, but e.g. B. can be up to 20 atm or more.

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Step (4), the reaction between the ester of the formula VI and two equivalents of base to bring about the elimination of hydrogen chloride and the internal condensation with delivery of the desired product of the formula I, is preferably carried out at low temperature, preferably not more than
0 ⁰ C ₁ carried out in the presence of an inert solvent. The choice of solvent is not critical and any polar or non-polar, protic or aprotic solvent can be used. Preferred solvents are
t-butanol, dimethylformamide and ether, e.g. B. dioxane, tetrahydrofuran or dimethoxymethane. Any suitable inorganic or organic base can be used; preferred bases are sodium or potassium ethoxide, tert-butoxide and tert-amyloxide.

The invention is illustrated in more detail by means of the following examples.

example 1
Step 1

A solution of 81.4 g = 0.40 mol of 2,3-epoxy-2-methyl-5,5,5-trichloropentane in 100 ml of absolute ethyl alcohol became a stirred solution of 9.2 g = 0.40 mol of sodium and 64.2 g =
0.40 mole of diethyl malonate were added in 900 ml of absolute ethyl alcohol at 40 ⁰ C for a period of 25 minutes. The reaction mixture was then stirred for 30 minutes _and the temperature was raised to 70 ° C. and stirring was continued for a further hour. 275 ml of 2N HpSO ^ were added and the mixture was washed twice with 500 ml of ethyl ether
extracted. The ethereal extracts were combined, dried under anhydrous MgSO ^ and evaporated, 3-carbethoxy-5,5-dimethyl-4- (2,2,2-trichloroethyl) -T-butyrolactone in
a yield of 70 % was obtained.

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Example 2
Level 2

A solution of 57 g = 0.18 mol of 3-carbethoxy, 5 ^ '5-dimethyl-4- (2,2,2-tΓichloΓäthyl) -y ^ι -butyΓolacton and 3 ml of water in 2? 0 ml DIlF was 3 hours stirred at 130 ⁰ C. After cooling the reaction mixture, water and ether were added and stirring was continued for an additional 0.5 hour. The ethereal layer was separated and evaporated, 5,5-Di "ethyl-4- (2,2,2-trichloroethyl) -3 * -butyrolactone was obtained in a yield of 95%.

Example 3

Level 3

21.9 g = 0.09 mol of 5,5-diethyl-4- (2,2,2-trichloroethyl) -T-butyrolactone and 42.8 g = 0.36 mol of SOCl ₂ were 18.4 g = 0 , 4 mol of ethanol and 1 g of FeCl, mixed. The mixture was then heated to 80-85 ° C for 3 hours in a pressure reaction vessel at 20 atm. Ethyl 4-chloro-4-methyl-3- (2,2,2-trichloroethyl) pentanoate was isolated in a yield of 60% from the reaction mixture.

Example 4
Level 4

1.48 g = 0.005 mol of ethyl 4-chloro-4-methyl-3- (2,2,2-trichloroethyl) pentanoate and 3.4 g = 0.03 mol of potassium tert-butoxide were in 150 ml reacted dry tetrahydrofuran under a nitrogen atmosphere. The reaction was carried out at a temperature between -70 ⁰ C and -10 ⁰ C to give almost quantitatively a mixture of cis- and trans-ethyl-3- (2,2-dichlorovinyl) -2,2-dimethyl-cyclopropane-carboxylate .

709884/0946

Claims (3)

Claims 1.! Process for the preparation of chrysanthemic acid ester or ^ - ' a homologue thereof of the following formula: C = CH-CH - CH-COOR ^R l ^R 2 where "mean: R ^. and Rp, which can be the same or different Hydrogen atoms or an alkyl group with 1 to 6 Carbon atoms; R, and R ^ ,, which can be the same or different, a An alkyl group having 1 to 6 carbon atoms or a HeIo genatom or, together with the carbon atom to which they are attached, a cycloalkylidene group with up to 8 carbon atoms; and Rt- an alkyl group with 1 to 6 carbon atoms, characterized in that (1) an epoxy of the following formula: ^R 3 C-CH-CH-C < ^X 1 ^R 2 where X _x . is a halogen atom and R ^, Rp, R ^ and R ^ have the meanings given above, with a malonic acid ester of the following formula: 709884/0946 _Λ ORIGINAL INSPECTED COOR ₆ 2 III ^ COOR ₁ wherein R ^ is an alkyl group having 1 to 6 carbon atoms is, in the presence of one equivalent of a base to form a compound of the following formula: R.- C-CII ₀ -CH - CH-COOR, ^R 2 is implemented, (2) the lactone IV in the presence of an inert solvent to effect removal of the carbalkoxy group and to obtain a lactone of the following formula: R ₄ C-CH-CH-CH _{0 χ} / II ² 1 R-C C = O O ^R 2 is heated, (3) the lactone V with a chlorinating agent and or hydrochlorierenden with an alcohol RcOH, wherein R _c is as defined above, to induce a split ring, chlorination and esterification to give an ester of the following formula: 709884/0946 2732A56 - C-CH ₂ -CH-CH ₂ -COOR
HC V \ R ₂ Cl is implemented, the ester of the formula VI with two equivalents of a base to induce elimination of hydrogen chloride and treating an internal condensation to form the desired compound of Formula I. 2. The method according to claim 1, characterized in that in step (3) the ring cleavage, the chlorination and the esterification can be carried out simultaneously in the same reaction mixture. 3. The method according to claim 2, characterized in that SOCIp as the chlorinating agent, ethyl or propyl alcohol as alcohol Ri-OH and FeCl, can be used as a catalyst. ^. Method according to claim 2 or 3 »characterized in that that step (3) is carried out under superatmospheric pressure. 7 0 9 8 8 4 / Π 9 U 6