CH621547A5 - Process for the preparation of a lactone - Google Patents

Description

621,547

2

CLAIMS comprising an aqueous phase and an organic phase obtained by an inert solvent immiscible with water.

1. Method for preparing a lactone of formula: 5. Method according to claim 4, characterized in that

£ m leads step 2) to room temperature in the presence of a

5 phase transfer catalyst.

. C = CH - CH — CH — COOR5 (I) 6. Method according to one of claims 1 to 5, characterized in that p / I J-_n that steps 1) and 2) are carried out in sequence without isolating the compound

4 1 Ar V— of formula Y.

R

in which

R! and R2, identical or different, are a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms;

R3 and R4, identical or different, are a hydrogen atom, a The present invention relates to a process for the preparation of an alkyl group having 1 to 6 carbon atoms or a halo- lactone atom which are intermediate compounds useful for the pregene or, together with 1 carbon atom to which they are attached, paration of synthetic pyrethroids having an insecticidal activity, form a cycloalkylidene group having up to 8 atoms more particularly, the invention relates to a carbon process , and preparation of 3-carbalkoxy-4- (vinyl-2,2-disubstituted) -

Rs is an alkyl group having from 1 to 6 carbon atoms, 5,5-disubstituted-y-butyrolactones of formula:

characterized in that

1) An unsaturated alcohol of the formula is reacted:

Ri. C = CH-CH-CH-COOR5 (I)

R2-p-CH = CH2 (III) R / R, —.C C = 0 HO

in which Rt and R2 have the above meanings in which Rx and R2, which are identical or different, are one with a compound of formula: hydrogen atom or an alkyl group having from 1 to 6 atoms

R3 Xj carbon, preferably the methyl group, R3 and R4, which are identical

\ / • 30 ticks or different, are a hydrogen atom, an alkyl group

C (IV)

having from 1 to 6 carbon atoms, preferably methyl, or a halogen atom, preferably fluorine, chlorine or bromine, or,

together with the carbon atom to which they are attached, form one in which Xj and X2, identical or different, are a cycloalkylene group atom having up to 8 carbon atoms, and R5 is d halogen, and R3 and R4 have the meaning above 35 an alkyl group having 1 to 6 carbon atoms, preferably to form a compound of formula: methyl

R3 Rx The lactones of formula I can be converted into 2,2-disubsti-

\ / killed-3- (vinyl-2,2-disubstituted) -cyclopropanecarboxylates of alkyl

R4-C-CH2-CH-C-R2 (V) of formula:

/ I \ 40

Xi X2 OH R3

2) The compound of formula V is reacted with an equivalent \. .

ti 1 »r 1 /> 1 .C'_ vil L / ld— L / irl— (11)

d of a base to form a compound of formula: y y v '

\ Z1 45 R4 / \

R4- ^ C-CH2-CH-C '(VI) Ri R2

in which R6 is an alkyl group having from 1 to 6 car-1 2 bone atoms and R1, R2, R3 and R4 have the above meaning, by the method

3) The compound of formula VI is reacted with a malonate described and claimed in British patent No. 1503857. dialkyl of formula: 50 l6S compounds of formula II can be directly converted,

COOR5 by esterification or transesterification, into pyrethroids of

/ synthesis of the type described for example in "Nature", 246.16 novem-

CH \ (VI1) bre 1973, pp. 169-170.

COOR The present invention therefore relates to a process for preparing

555 ration of a lactone of formula I which comprises:

in which R5 has the above meaning, in the presence of two j) The faction of an unsaturated alcohol of formula:

equivalents of a base to form the compound of formula I.

Ri

2. Method according to claim 1, characterized in that V

leads step 1) in the presence of an inert solvent and an R2 - C — CH = CH2 (III) catalyst

which is a free radical initiator, an ultraviolet radiation or 60 /

a salt of a transition element, said salt being used alone or under ^

the form of an association complex with an electron donor. in which Rx and R2 have the above meanings with a

3. Method according to claim 2, characterized in that the compound of formula:

catalyst is benzoyl peroxide or a coordinate complex 65 R3. Xt nation of FeCl3,6H20 with n-butylamine. \ /

4. Method according to one of claims 1 to 3, characterized in / \ (IV) that one conducts 1 step 2) in a two-phase reaction mixture R4 X2

3

621547

in which Xt and X2, identical or different, are an atom Steps 1) and 2) are preferably carried out without isolating the halogen, preferably chlorine or bromine, and R3 and R4 have the compounds of formula V.

above meanings, to form a compound of formula:

Ik Ri

The following examples illustrate the invention.

R4 ^ -CH2-CH- 5 Example 1:

/ \ \ Step 1

X, X, OH

Step 1

A solution of 43 g (0.5 mol) of 2-methyl- was heated to reflux.

2) The reaction of the compound of formula V with a 3-buten-2-ol equivalent, 6.75 g (0.025 mol) of FeCl3.6H 2 O, 7.25 g of a base to form a compound of formula: io ( 0.1 mol) of n-butylamine and 227.5 g (1.5 mol) of carbon tetrachloride R, Rj in 110 g of DMF for 6 h, then cooled to

/ ordinary temperature. Water and ethyl ether were added and

^ ~ —CH — C (VI) stirred the mixture for 10 min. We separated the etheric layer and

'\ y> it was evaporated to obtain 75% of the theoretical amount of

1 2 15 2-methyl-3,5,5,5-tetrachloro-2-pentanol.

3) Reaction of the compound of formula VI with an NMR malonate in CDCl3: 1.37 (6H, singlet, methyl groups); dialkyl of formula: 8 2.33 (1H, singlet, OH); 8 2.78-3.63 (2H, AB part of the system

^ COORj ABX, —CH2—); 8 4.05 (IH, X part of the ABX system, -CH =).

CH2 (VII) 20 Example 2:

^ COORj Step 1

in which Rs has the above meaning, in the presence of two A solution of 86 g (1 mol) of 2-methyl-3- was heated to reflux

equivalents of a base to form the compound of formula I. buten-2-ol and 1.5 g of dibenzoyl peroxide in 1000 ml of

_. . , carbon tetrachloride by separating the water azeotropically during

We now have a more detailed description of the steps lasting 4 h Qn then have spent 15 moJ of dibe and we are towing the present process arasi than the variant. a uiyi fc chauff dant 2Q h Qn has cooled fc m-la

L stage 1), that is to say the reaction between 1 unsaturated alcohol of reaction, it was washed with an aqueous solution of NaHC03 and one formulates III and the compound of formula IV, is carried out preferably with dry, e 0n tetrachloride obtained 2-methyl-

in the presence of an inert solvent. The choice of solvent is not critical 3,5,5,5-tetrachloro-2-pentanol with a yield of 75%.

tick and any polar aprotic or NMR solvent can be used in CDCl3: 8 1.37 (6H, singlet, methyl groups);

not polar. Preferably, the solvents are dimethylformamide g 2) 33 (1H) if H OH). 5 23.3.63 (2 H, AB part of the system

(DMF) and carbon tetrahatogenides ABX, -CH2 -), 8 4.05 (1 H, X part of the ABX system, -CH =).

Preferably, the addition reaction is carried out at high temperature.

and using a catalyst. Suitable catalysts are Example 3 •

free radical initiators, ultraviolet light and salts of 35

transition elements, either alone or in coordination complexes with electron donors such as amines. A solution of 86 g (1 mol) of 2-methyl-3-buten- was heated.

suitable free radical initiators are, for example, azobisiso-2-ol and 18.6 g of dibenzoyl peroxide in 250 g (1.5 mol) of butyronitrile, benzoyl peroxide and t-butyl perbenzoate; bromochlorodifluoromethane at 80 ° C in a reactor under suitable transition element salts are, for example, 40 pressures (pressure 10.5 kg / cm2) for 2 h. After cool down

cuprous or cupric halides and ferrous halides or ment, distillation (bp = 41-47 ° C / 0.5 mm Hg) gave the ferric; suitable organic amines which can be used 3-bromo-5-chloro-5,5-difluoro-2-methylpentane-2-ol with one in the coordination complexes are, for example, n-butyl- yield of 70 %.

amine, diisopropylamine and triethylamine. NMR catalysts in CDCl3: 8 1.42 (6H, singlet, methyl groups);

preferred are benzoyl peroxide and FeCl3.6H20 in combination 45 8 2.27 (1H, singlet, OH); 8 2.63-3.37 (2H, AB part of the system with n-butylamine. ABX, - CH2—); 8 4.07 (IH, X part of the ABX system, - CH =).

Stage 2) is preferably carried out, that is to say the reaction between the compound of formula V and an equivalent of a base to form Example 4:

an epoxide of formula VI in a two-phase compressed system- Step 2

nant an aqueous phase and an organic phase. 50 A solution of 11 95 (0 05 mol) of 2-methyl-3,5,5,5-tetra- can be used.

any inert water-immiscible solvent as chloro.2.pentanol solvent in a mixture of 50 ml of CH2Cl2 and 50 ml of organic, and the preferred organic solvent is methyl chloride-H2O, 2) 08 g were added (0.05 mol) of NaOH. The lene mixture was stirred. The reaction is preferably carried out at normal reaction temperature for 2 h to obtain an almost quantitative yield.

preferably, in the presence of a 2,3-epoxy-2-methyl-5,5,5-trichioropentane ^ transfer catalyst.

phase for example an ether crown or a halide of tetra-55 NMR in CDCl3: 8 1.37 (6H, doublet, methyl group);

alkylammonium, preferably tetrabutyl chloride 3 77.3 33 (3Hi tem ABX (muitiplet), -CH2-CH =). ammonium. Any suitable organic or inorganic base can be used as the base, preferably p hydroxide,

• <• thX € ÎYlVlë j '

sodium. -

Stage 3) is carried out, that is to say the reaction between the epoxide of Stage 2

formula VI and the dialkyl malonate of formula VII in the presence of A a solution of 12.4 g (0.05 mol) of 3-bromo-5-chloro-

two equivalents of a base. Any base 5,5-difluoro-2-methylpentane-2-ol can be used in a mixture of 50 ml of suitable organic or inorganic, preferably CH2Cl2 ethoxide and 50 ml of water, added 2.08 g (0.05 mol) NaOH. We have sodium or sodium methoxide. The reaction mixture is preferably stirred for 2 h to obtain a yield.

reaction in the presence of an inert solvent. The choice of solvent is only 65 almost quantitative in 5-chloro-5,5-difluoro-2,3-epoxy-2-

not critical and any protic or methylpentane solvent can be used. Mp = 34-37 ° C / 8 mm Hg.

aprotic, polar or non-polar, preferably ethanol or NMR in CDCl3: 8 1.32 (6H, doublet, methyl groups);

methanol. 8 2.27-3.17 (3H, ABX system (multiplet), - CH2 — CH =).

621,547

Example 6

Stage 3

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 was added to a stirred solution of 20.7 g (0.9 mol) of sodium and 144.5 g (0.9 mol) of diethyl malonate in 900 ml of absolute ethyl alcohol at 40 ° C over 25 min. The reaction mixture was then stirred for 30 min, the temperature was raised to 70 ° C and stirring continued for another 1 h. 275 ml of 2N H2SO4 was added and the mixture was extracted twice with 500 ml of ethyl ether. The etheric layers were combined, dried over anhydrous MgSO4, and then evaporated. 200 ml of n-pentane was added and 3-carbethoxy-4- (2,2-dichlorovinyl) -5,5-dimethyl-y-butyrolactone precipitated. The yield was 70%.

M.p .: 72.5-73 ° C. NMR in CDCl3: 8 1.30 (3 H, triplet, CH3 in the ethylester group); 8 1.33 (3H, singlet, methyl group); 8 1.53 (3H, singlet, methyl group); 8 3.42-4.03 (2 H, multiplet,

4

2 - CH =); 8 4.27 (2H, quartet, CH2 in the ethylester group); 8 5.87 (1 H, double doublet, CH in the vinyl group).

Example 7:

5 Steps 1 and 2

A solution of 86 g (1 mol) of 2-methyl-3-buten-2-ol and 1.5 g of benzoyl peroxide in 1000 ml of carbon tetrachloride was heated to reflux, azeotropically separating the water for 4 h. 1.5 mol of benzoyl peroxide was then added and the heating was continued for 20 h. To the cooled reaction mixture was added 0.5 g of tetrabutylammonium chloride and 40 g (1 mol) of sodium hydroxide in 165 ml of water and the mixture was heated for 8 h. The reaction mixture was cooled and the two phases were separated, then the organic phase was distilled to obtain 2,3-epoxy-2-methyl-5,5,5-trichloropentane with a yield of 80%. Mp: 76 ° C / 10 mm Hg.

NMR in CDCl3: 81.37 (6H, doublet, methyl group); 8 2.77-3.33 (3 H, multiplet, -CH2-CH =).

R