CH641135A5 - Alkadienes and alkenols - Google Patents

Abstract

Compounds of the formulae II and IV, in which R<1> and R<2> have the definition given in Claims 1 and 4, respectively. They are valuable intermediates in the preparation of insecticides. Processes for their preparation are also described. <IMAGE>

Description

The invention relates to alkane dienes and alkenols which are useful as intermediates for the preparation of insecticides and alkarazides.

US Pat. No. 4,183,948 describes new intermediates for pyrethroid insecticides according to the following formula I.

It's about

12 il

R R C = CH-CH-CH-C-Q \ /

C.

30th

: L \

35

C 3 ^ 3

wherein one of the substituents R1 and R2 is a group of the formula

WCF2-

wherein one of the two substituents R1 and R2 represents trifluoromethyl and the other trifluoromethyl or difluoromethyl.

5. A process for the preparation of a diene according to claim 1, characterized in that a ketone is of the formula in which W is hydrogen, fluorine or chlorine and the other of the two substituents R1 and R2 is a group of the formula 40Y

\

X-C-

t z

45

means in which X, Y and Z independently of one another are hydrogen, fluorine or chlorine and Q is lower alkoxy having 1-3 C atoms.

Within this group of preferred compounds 50, those are particularly preferred in which both R1 and R2 are trifluoromethyl groups. The compounds of the formula I can be reacted by reacting a diene of the formula

/ CH3

55 \ /

C = CH-CH = C

\

II

R

CH.

wherein R1 and R2 have the meaning given in claim 4, characterized in that the corresponding compound of formula IV

60 can be obtained with a lower alkyl ester of diazoacetic acid. The desired compound of the formula I is thereby obtained directly. The process is preferably carried out using an excess of the diene as a solvent for the alkyldiazoacetate and in the presence of a metallic catalyst, e.g. powdered copper or copper bronze.

In a modification of this process, a compound of formula III by reaction of the unsaturated

3rd

641 135

saturated alcohol of formula IV can be obtained with a lower alkyl di-azoacetate and can be obtained by dehydration with a dehydrating agent, e.g. Phosphorus pentoxide, are converted into the compound of formula II, wherein Q represents lower alkoxy.

oh iii r1r2c-ch_-ch-ch-c-q

2 \ /

c

/ \

ch_ ch.

oh ch.

r1r2c-ch2-ch = ç

\

iv ch.

This variant of the diazoacetate process is not applicable to the preparation of compounds in which one of the substituents r1 and r2 is halogen, but is useful for the preparation of compounds in which r1 and r2 are both trifluoromethyl or in which one of the substituents r1 and r2 Trifluoromethyl and the other Difluormethyl represents.

The present invention relates to the new compounds of the formula II

\ / ch3

c = ch-ch = c ii

2 / \

R2 CB3

wherein R1 and R2 are as defined above, and compounds of the formula

'c

.2 / \

ch -ch = c ^

ch.

iv ch.

wherein r1 represents trifluoromethyl and r2 trifluoromethyl or difluoromethyl.

The compounds of formula IV can be obtained by reacting a ketone of the formula

0

1 "2 r -c-r with 3-methylbut-l-ene, preferably at elevated pressure. The corresponding compounds of the formula V are obtained by dehydration, for example with phosphorus pentoxide, of the compounds of the formula IV.

The compounds of formula V in which r1 and r2 are both haloalkyl groups or in which one of the substituents r1 and r2 is haloalkyl and the other is methyl can also be reacted by reacting the corresponding ketone of the formula

0

1! F 2 r -c-r with the ylide obtained by treating a 3,3-dimethyl-allyltriphenylphosphonium halide, preferably the chloride or bromide, with a suitable dehydrohalogenating agent, e.g. an alkyl lithium compound such as 5 n-butyllithium. The phosphonium halide can be prepared by reacting triphenylphosphine with a 3,3-dimethylallyl halide. Dienes as obtained with this process are those of the formula V, in which R1 and R2 have the meanings given in Table 10 below:

R1

R2

cf3

chf2 chf2 ch3

cf2c1

cf2ci cf3

15 CHF,

cf3 cf3 cf2ci chf2

20th

Examples of compounds of the formula IV are 5-hydroxy-2-methyl-6,6,6-trifluoro-5-trifluoromethylhex-2-ene and 5-hydroxy-2-methyl-6,6-difluoro-5-trifluoromethylhex -2-enes, and these can be dehydrated to 2-methyl-6,6,6-25 trifluoro-5-trifluoromethylhexa-2,4-diene and 2-methyl-6,6-di-fluoro-5-trifluoromethylhexa- 2,4-diene as examples of compounds of formula II.

The invention is illustrated by the following examples.

30th

example 1

This example illustrates the preparation of 1-chloro-1,1-difluoro-2-chlorodifluoromethyl-5-methylhexa-2,4-diene of the formula

35 CH. CF-Cl

N /

J) C = CH-CH = C

ch3 cf2ci

40

a) Preparation of 3,3-DimethylallyI-triphenylphos-phonium bromide

A mixture of 50.0 g of 3,3-dimethylyl bromide, 88.0 g of triphenylphosphine and 500 ml of dry toluene was heated under reflux for one hour to reflux temperature and then left to stand at room temperature for 18 h. The resulting white precipitate of 3,3-dimethylalyl-triphenylphosphonium bro-mid (mp. 242 ° C.) was filtered off, washed with diethyl ether and dried.

b) Preparation of l-chloro-l, l-difluoro-2-chlorodifluoromethyl-5-methylhexa-2,4-diene

65.0 ml of a 15% solution of n-butyllithium in hexane slowly added to a vigorously stirred suspension 55 of 65.0 g of 3,3-dimethylallyl-triphenylphosphonium bromide in 500 ml of dry petroleum ether (bp 30-40 ° C.) Given 0 ° C under nitrogen, the mixture was left at room temperature for 18 h. The mixture was then cooled to 0 ° C. and 31.44 g of 1,3-dichlorotetra-60 ftuoracetone were added. The mixture was then left to stand at room temperature for a further 2 hours, and the precipitate formed was filtered off. The filtrate was concentrated in vacuo to a volume of about 70 ml and poured onto a column filled with aluminum oxide, whereupon the remaining solvent was removed at atmospheric pressure and a temperature of 69.degree. The remaining liquid was fractionally distilled and the fraction with bp of 79-80 ° C / 20 mm Hg

641135

was isolated and with the help of IR and NMR spectra

as 1-chloro-l, l-difluoro-2-chlorodifluoromethyl-5-

methylhexa-2,4-diene identified.

NMR (CC14) p.p.m. 1.88-1.94 (m, 6H); 6.3 (d, 1H); 7.08

(d, lH).

Example 2

Using a procedure analogous to that described in Example 1, the following dienes were prepared from the corresponding ketones:

(i) 2-methyl-5-trifluoromethylhexa-2,4-diene from 1,1,1-tri-fluoroacetone.

NMR (CCU) p.p.m. 1.76-1.82 (m, 9H); 5.85-6.00 (m, lH); 6.62-6.78 (m, 1H).

(ii) 1,1-difluoro-2-chlorodifluoromethyl-5-methylhexa-2,4-diene from l-chloro-l, l, 2,2-tetrafluoroacetone.

IR (liquid film) - 3000, 1650, 1265 cm "\

(iii) 1,1-difluoro-2-difluoromethyl-5-methylhexa-2,4-diene from 1,1,3,3-tetrafluoroacetone.

NMR (CC14) P-P-m. 1.90-2.02 (m, 6H); 5-65-7.10 (m, 4H).

Example 3

This example illustrates the preparation of 5-hydroxy-2-methyl-6,6,6-trifluoro-5-trifluoromethylhex-2-ene.

A stirred mixture of 235 g of hexafluoroacetone and 100 g of 3-methylbut-1-ene was at a pressure of 17 atm. heated to 125 ° C for 20 h. Distillation of the product obtained under reduced pressure gave 5-hydroxy-2-methyl-6,6,6-trifluoro-5-trifluoromethylhex-2-ene as an easily mobile, colorless liquid of bp 43 ° C / 15 mm Hg. NMR ( CCU) ppm 1.77 (d. 6H); 2.58-3.00 (m, 3H); 5.0-5.4 (m, 1H).

Example 4

5-Hydroxy-2-methyl-6,6-difluoro-5-trifluoromethylhex-2-ene was prepared as pentafluoroacetone using the same procedure as described in Example 3.

NMR (CCU) p.p.m. 1.78 (d. 6H); 2.5-2.75 (m, 3H); 5.18 (m, 1H); 5.80 (t, lH);

Example 5

This example illustrates the preparation of ethyl - (+) - cis / trans-3- (2-hydroxy-3,3,3-trifluoro-2-trifluoromethylprop-1-yl) -2,2-dimethylcyclopropane carboxylate.

A solution of 9.12 g of ethyl diazoacetate in 400 ml of di-chloromethane was added dropwise to 18.9 g of 5-hydroxy-2-methyl-6,6,6-trifluoro-5-trifluoromethylhex-2-ene in the presence of a catalytic solution over 48 h Amount of anhydrous copper (II) sulfate at 110-120 ° C.

The resulting mixture was washed with water, dried over anhydrous magnesium sulfate and distilled at 0.15 mm Hg, collecting various fractions in the range of 68-90 ° C. NMR, IR and MS showed that these fractions essentially consist of the (±) -cis and (+) - trans isomers of ethyl 3- (2-hydroxy-3,3,3-trifluoro-2-trifluoromethylprop- l-yl) -2,2-dimethylcyclo-propane carboxylate in varying proportions.

NMR (cdci3) p.p.m. 1.04-1.40 (m, 9H); 1.55-2.43 (m, 4H); 4.00-4.37 (m, 2H).

Example 6

Using the procedure analogous to that described in Example 5, 5-hydroxy-2-methyl-6,6-difluoro-5-trifluoromethylhex-2-ene was converted to ethyl- (±) -cis / trans-3- (2-hydroxy-3, 3-difluoro-2-tri-fluoromethylprop-l-yl) -2,2-dimethylcyclopropane carboxylate.

NMR (CCU) P-P-m. 1.3-2.4 (m, 13H); 4.0-4.35 (m, 2H); 4.6-4.8 (m, 1H); 5.2-6.4 (m, 1H).

Example 7

This example illustrates the preparation of ethyl (±) cis / trans-3- (3,3,3-trifluoro-2-trifluoromethylprop-l-en-l-yl) -2,2-dimethylcyclopropane carboxylate.

A mixture of 4.62 g of ethyl (±) cis / trans-3- (2-hydroxy-3,3,3-trifluoro-2-trifluoromethylprop-l-yl) -2,2-dimethyl-cyclopropanecarboxylate , 2.2 g of phosphorus oxychloride and 5.3 ml of dry pyridine was heated to 110 ° C over 65 h, after which it was poured onto ice water and stirred for 5 h. The mixture was then extracted with diethyl ether, and the extracts were washed with water and dried over anhydrous sodium sulfate. After removal of the ether by concentration under reduced pressure, the remaining oil was vacuum distilled, and ethyl - (+) - cis / trans-3- (3,3,3-trifluoro-2-trifluoromethylprop-l-en-l-yl) - 2,2-dimethylcyclopropanecarboxylate was obtained as a colorless oil of bp 60-65 ° C /, 5 mm Hg.

NMR (CDCU) p.p.m. 1.15-1.39 (m, 9H); 1.75-2.60 (m, 2H); 4.02-4.34 (m, 2H); 6.36 and 7.36 (dd, lH).

Using the same procedure as described in Example 5, the ethyl esters of the formula II mentioned below were obtained from the dienes also mentioned by reaction with ethyl diazoacetate.

(i) Ethyl- (±) -cis / trans-3- (3,3-difluoro-2-difluoromethyl-prop-1-en-1-yl) -2,2-dimethylcyclopropane carboxylate from 1,1-difluoro-2 -difluoromethyl-5-methylhexa-2,4-diene.

NMR (CCU) p.p.m. 1.25-1.44 (m, 9H); 1.60-2.40 (m, 2H); 4.0-4.30 (m, 2H); 5.58-7.34 (complex, 3H).

(ii) Ethyl - (+) - cis / trans-3- (E / Z-2-trifluoromethylprop-l-en-l-yl) -2,2-dimethylcyclopropane carboxylate from 2-trifluoromethyl-5-methylhexa-2,4 -serve.

NMR (CCU) p.p.m. 1.10-1.40 (m, 9H); 1.50-2.10 (m, 5H); 4.0-4.38 (m, 2H); 5.24-6.46 (m, lH).

(iii) ethyl (±) cis / trans-3- (3-chloro-3,3-difluoro-2-chlorodi-fluoromethylprop-1-en-1-yl) -2,2-dimethylcyclopropane carboxylate from l -Chlor-l, l-difluoro-2-chlorodifluoromethyl-5-methylhexa-2,4-diene.

NMR (CCU) p.p.m. 1.28-1.42 (m, 9H); 1.78-2.60 (m, 2H); 4.08-4.26 (m, 2H); 6.20 and 7.16 (dd, lH).

(iv) ethyl - (+) - cis / trans-3- (E / Z-3,3-difluoro-2-chlorodifluoromethylprop-1-en-1-yl) -2,2-dimethylcyclopropane carboxylate from l , l-difluoro-2-chlorodifluoromethyl-5-methylhexa-2,4-diene.

NMR (CCU) p.p.m. 1.24-1.52 (m, 9H); 1.64-2.50 (m, 2H); 3.90-4.30 (m, 2H); 5.50-7.04 (m, 2H).

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Claims (9)

641135 2nd PATENT CLAIMS 1. A formula II diene ■ / CH1 \ / C = CH-CH = C. (ii) CH. wherein one of the two substituents R1 and R2 is a group of the formula WCF2- represents, where W is hydrogen, fluorine or chlorine and the other of the two substituents R1 and R2 is a group of the formula Y \ x-r represents z, where X, Y and Z independently of one another are hydrogen, fluorine or chlorine. 2. Diene according to claim 1, wherein R1 and R2 independently represent trifluoromethyl, difluoromethyl or chlorodi-fluoromethyl and wherein one of the two substituents R1 and R2 can additionally be methyl. 3. A compound according to claim 1, wherein R1 and R2 represent the trifluoromethyl group. 4. Compound of formula IV OH 1 2l RR C-CH ^ -CH = C / CH3 "CH. (IV) 1 »2 R -C - R with the ylide obtained by dehydrohalogenating 3,3-dimethylallyl-triphenylphosphonium halide. 6. Process for the preparation of a diene of formula II CH. C = CH-CH = C R / \ (ii) CH. OH CH., 12 'S R R C-CH.-CH = C Z \ CH3 (IV) is dehydrated by treatment with phosphorus pentoxide. 7. A process for the preparation of a compound according to claim 4, characterized in that a ketone of the formula 0 R U- R wherein R1 and R2 have the meaning given in claim 4, is reacted with 3-methylbut-l-ene. 10. The method of claim 7, carried out under increased pressure. 15