HU183162B - Process for preparing gamma-unsaturated carboxylic acid derivatives - Google Patents

Abstract

The present invention relates to a process for the preparation of γ-unsaturated carboxylic acid derivatives of the formula (I); wherein R is C 1 -C 4 alkyl, phenyl (C 1 -C 4) alkyl or phenoxyphenyl (C 1 -C 4) alkyl, R 2 and R 3 are independently hydrogen, C 1-4 alkyl or phenyl; , R 7 is hydrogen or C 1-4 alkyl, R 4 is hydrogen, C 1-6 alkyl or C 3-5 cycloalkyl, and R 5 is hydrogen or C 1-4 alkyl. -1-

Description

The present invention relates to a process for the preparation of γ-unsaturated carboxylic acid carboxylic acids of formula (I) which are intermediates for the preparation of pyrethroid insecticides. The preparation of these insecticides is, for example, described by

United Kingdom Patent 285,350; South African Patent 733,528;

U.S. Patent Nos. 727,900 and 3,808,260. However, the novel compounds of the invention were not used in this process.

In the general formula (I)

R is (1-4C) alkyl, phenyl (1-4C) alkyl or phenoxyphenyl (1-4C) alkyl,

R ² and R ³ are each independently hydrogen, C 1-4 alkyl or phenyl,

^R7 is hydrogen or C1-4 alkyl, and

R ^{4 is} hydrogen, C 1-6 alkyl, or C 3-5 cycloalkyl, and

R ^{5 is} hydrogen or C 1-4 alkyl.

According to the invention, the process is carried out by:

a) alkenol of formula II wherein R ² , R ³ , R ⁴ and

R ⁵ is condensed with the above orthoester R ⁷ -CH ₂ C (OR) ₃ , wherein R and R ⁷ are acidic catalysts at a temperature of from 20 to 250 ° C, preferably 0.001 to 20% by weight based on the amount of alkenol, preferably in the presence of phenol or aliphatic acid having from 2 to 6 carbon atoms, or

b) alkenol of formula II wherein R ² , R ³ , R ⁴ and

Condensed ^R5 are as defined above, R ⁷ -CH 2 C (OR) orthoester of Formula 3 wherein R ⁷ and R are as defined above, an acidic catalyst at a temperature of 120 'during ^J C, and the resultant (III) mixed orthoester of formula further reacting with the orthoester R ⁷ -CH ² C (OR) _{3 in} the presence of an acid catalyst at 100-250 ° C while removing the resulting alcohol, or

c) a mixed orthoester of formula III wherein R ² , R ³ , R ⁴ , R ⁵ , R ⁷ and R are reacted with an orthoester of formula R ⁷ -CH ₂ C (OR) ₃ in the presence of an acidic catalyst At a temperature of 100-250 ° C while removing the resulting alcohol and optionally transesterifying the resulting compound of formula (I) as described above.

The process comprises reacting an alkenol with an orthoester to produce a γ-unsaturated carboxylate of formula (I). It has been found that the mixed orthoester of formula (III) is an intermediate and can be isolated. Other compounds may be used in the preparation of this intermediate, in practice, to yield the compound of formula II. For example, alkenol can be reacted with a suitable ketene acetal to form a mixed orthoester to form a γ-unsaturated carboxylate of formula (I).

Examples of alknols are allyl alcohol, crotyl alcohol,

4-methyl-1-phenyl-3-penten-2-ol, 4-methyl-3-penten-2-ol, cinnamyl alcohol, 3-methyl-2-buten-1-ol, 2,4-dimethyl- 3-penten-2-ol, 5-methyl-4-hexen-3-ol, 2-methyl-2-hepten-4-ol, 1-cyclopentyl-3-methyl-2-buten-1-ol. .

These alkenols are readily available or readily prepared from commercially available raw materials.

Preferably, 3-methyl-2-buten-1-ol is used. 3-Methyl-2-buten-1-ol is a by-product of the isoprene production.

Orthoesters having an acidic moiety of alkanoic acid such as acetic acid, propionic acid, butyric acid, isobutyric acid and valeric acid, and an alcoholic moiety of a C 1-4 alkanol such as methanol and ethanol such as ethyl orthopropionate, methyl orthoacetate and ethyl orthoacetate. The orthoester acid and alcohol parts are chosen such that the desired R and R ⁷ groups is obtained in the γ-unsaturated carboxylates. The orthoesters are readily prepared by alcoholysis of the corresponding nitriles. Ethyl orthoacetate is preferably used in the preparation of the γ-unsaturated carboxylates used in the further steps of the process of the present invention for the preparation of dihalo-vinylcyclopropane carboxylate.

Although the reaction rate between alkenol and orthoester is accelerated by an acid catalyst, its use is not required. Examples of acid catalysts are phenols such as phenol itself, followed by ortho-, meta or para-nitrophenol, ortho-, meth- or para-cresol, ortho-, meta- or para-xylene, 2,6-dimethylphenol, 2 , 6-di-tert-butylphenol, 2,4,6-tri-sec-butylphenol, 2,4,6-tri-tert-butylphenol, 4-methyl-2,6-di-tert-butyl -phenol, 4-methyl-3,5-di-tert-butylphenol, hydroquinone, 2,5-di-tert-butylhydroquinone, or β-naphthol; C2-C6 aliphatic acids such as acetic acid, propionic acid, butyric acid, isobutyric acid, cyclohexane carboxylic acid, valeric acid, aromatic carboxylic acids such as benzoic acid, meta-chlorobenzoic acid; sulfonic acids such as benzenesulfonic acid, p-toluenesulfonic acid band; inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid; and Lewis acids such as zinc chloride, iron (III) chloride, mercury (II) acetate. Generally, phenols, C2-C6 aliphatic carboxylic acids and aromatic acids are used as catalysts to avoid side reactions such as dehydration of the alkenol.

The process does not require the use of solvents, but solvents which do not adversely affect the reaction or the product may be used. Examples of suitable solvents include decalin, n-octane, toluene, ortho, meth or para-xylene, di-n-butyl ether, Ν, Ν-dimethylformamide.

Generally, stoichiometric amounts, i.e. molar equivalents of alkenol and orthoester, are used, but it is preferred that the orthoester be used in excess, for example, from 20 to 100% or more. The acid catalyst is used in an amount of 0.001 to 20% by weight, preferably 1 to 15% by weight, based on the amount of alkenol present.

The procedure is carried out at 20-250 ° C. Preferably, the reaction is carried out in two steps, the first step at a temperature between 20 and 120 ° C and the second step at a temperature between 100 and 250 ° C. In the case where ethyl orthoacetate is used as the reaction partner and the reaction is carried out at atmospheric pressure, the first step is usually carried out at 100-120 ° C, the ethanol formed is removed by distillation, and the second step is usually between 140-170 ° C. carried out.

In the transesterification of γ-unsaturated carboxylate, γ-unsaturated carboxylate and alcohol may be used in molar equivalents, but generally

-2183 162 reaction partners are used in excess. The use of ethyl ester is suitable, in particular, together with sodium catalyst, as a catalyst. Ethanol developed during the reaction is removed from the reaction mixture. Toluene may be used as the solvent.

In the examples and the description, the temperatures are given in degrees Celsius and the concentration is in% by weight. The boiling points were determined under reduced pressure; pressure is given in millimeters of mercury, such as fp. = 116 / 0.18 mmHg means that the boiling point measured at 0.18 mmHg is 116 “C.

For IR spectra, only the most characteristic absorption maxima are included.

Trimethylsilane is used as a standard in NMR spectra, and the abbreviations used in the NMR spectrum are as follows:

s = singlet d = doublet t = triplet q = quartet m = multiplet

These abbreviations may be preceded by other abbreviations, such as:

b = broad or d = double, for example dd = double doublet bt = wide triplet

The following examples illustrate the process of the invention in more detail.

Example 1

A) Preparation of ethyl 3,3-dimethyl-4-pentenoate

A mixture of 0.65 g of 3-methyl-2-butyn-1-ol, 2.43 g of ethyl orthoacetate and 50 mg of phenol is heated at 120 ° C with stirring. After 2 hours, the temperature was raised to 140 ° C and maintained for 20 hours. After ethanol evolution ceased, the mixture was dissolved in benzene to make a total volume of 5 mL. Gas chromatography analysis of the benzene solution showed that ethyl 3,3-dimethyl-4-pentenoate was 92% (physical properties in Example 3). «

B) Transesterification between 3-phenoxybenzyl alcohol and ethyl 3,3-dimethyl-4-pentenoate / 4 mg ethyl 3,3-dimethyl-4-pentenoate, 400 mg 3-phenoxybenzyl A mixture of alcohol and 16 mg of sodium ethylate in 10 ml of toluene was refluxed for 24 hours using a Dean-Rusk plug fitted with a molecular sieve to absorb the developing alcohol. The mixture was neutralized by addition of anhydrous ethereal hydrogen chloride. The neutral solution was poured into water, the ether layer was separated, dried over magnesium sulfate and distilled. There was thus obtained (3-phenoxybenzyl) -3,3-dimethyl-4-pentenate (520 mg, 70% yield). Mp: 155-158 ° C / 0.3 mmHg.

Analysis using the formula C ₂₀ H ₂₂ O ₃ :

Calculated: C, 77.39; H, 7.14; Found: C, 77; H, 7.11%.

NMR δ ppm (CCl ₄ ): 7.32-7.08 (m, 4H), 7.05-6.70 (m, 5H), 5.76 (dd, 1H), 4.92 (s, 2H), 4.96-4.70 (m, 2H), 2.22 (s, 2H), 1.08 (s, 6H).

Example 2

Preparation of ethyl 3,3-dimethyl-4-pentenoate

A mixture of 12.9 g (0.15 mol) of 3-methyl-2-buten-1-ol, 48.6 g (0.3 mol) of ethyl orthoacetate and 0.5 g of hydroquinone at 140 ° C for 20 hours heat while stirring. Ethanol that develops during heating is removed by distillation. After 20 hours, the mixture was distilled under reduced pressure to give 17.6 g (75% yield) of ethyl 3,3-dimethyl-4-pentenoate as the unreacted orthoacetate.

Mp: 74-78 ° C / 55 mmHg.

Example 3

Synthesis of ethyl 3,3-dimethyl-4-pentenoate

A) Phenol as catalyst in a mixture of g (0.5 mol) 3-methyl-2-buten-1-ol, 97 g (0.6 mol) ethyl orthoacetate and 7.0 g (0.075 mol) phenol 135-140 Heat at 9 ° C for 9-10 hours with stirring. As the reaction proceeds, ethanol is distilled off from the mixture. As soon as the ethanol evolution ceased, heating was stopped and the mixture was allowed to cool to room temperature. The mixture was then dissolved in diethyl ether and the ethereal solution was treated with 1N hydrochloric acid to decompose unreacted ethyl orthoacetate. The ethereal solution was washed first with saturated aqueous sodium bicarbonate solution, then with water and dried over magnesium sulfate. The dry solution was concentrated and distilled under reduced pressure. This gave 60.8 g (78% yield) of ethyl 3,3-dimethyl-4-pentenoate.

Mp .: 57-60 ° C / 11 mm Hg.

Analysis

NMR δ ppm (CCl ₄ ): 6.15-5.60 (dd, 1H) 5.15-4.68 (m, 2H), 4.02 (q, 2H), 2.19 (s, 2H) , 1.45-1.05 (m, 9H).

IR ^(cm-1): 3090, 1740, 1640, 1370, 1240, 1120, 1030, 995, 910th

B) With other catalysts

Ethyl 3,3-dimethyl-4-pentenoate can also be prepared in a similar manner as in Examples 1-A and 3 using the following catalysts: boric acid, phosphonic acid, isobutyric acid, mercury (II) acetate and hydroquinone.

C) Without catalyst

A mixture of 4.3 g of 3-methyl-2-buten-1-ol and 8.1 g of ethyl orthoacetate was heated with stirring. The temperature is slowly raised from room temperature to 165 ° C over 2 hours while evolving 2.21 g of ethanol is collected.

-3183 162

The temperature was maintained at 165 ° C for 26 hours, during which an additional 1.52 g of ethanol was collected. The rc mixture was then allowed to cool and then diluted with diethyl ether. The ethereal solution was washed with dilute hydrochloric acid, saturated aqueous sodium bicarbonate, and finally saturated aqueous sodium chloride. The solution thus washed was dried over magnesium sulfate and distilled to give 4.03 g (52% yield) of ethyl 3,3-dimethyl-4-pentenoate.

MP: 80-85 ° C / 52 mmHg.

D) via 1,1-diethoxy-1- (3-methyl-2-butenyl (oxy) ethane)

1. Preparation of 1,1-diethoxy-1- (3-methyl-2-butenyloxy) methane

A mixture of 4.3 g of 3-methyl-2-buten-1-ol and 16.2 g of ethyl orthoacetate was heated with stirring. The temperature is slowly raised to 120 [deg.] C. over 2 hours, during which time 1.8 g of ethanol is formed which is collected. The heating at 120 ° C was continued for 30 minutes and then the reaction mixture was distilled to remove 8.5 g of unreacted ethyl orthoacetate (b.p. 50-65 ° C / 57 mm Hg) followed by 4.25 g. 1-Diethoxy-1- (3-methyl-2-butenyloxy) ethane is obtained.

Mp: 75-76 ° C / 6 mmHg.

Analysis by CnH ₂₂ O ₃ :

Calculated: C, 65.31; H, 10.96; Found: C, 65.52; H, 10.74%.

2. Preparation of ethyl 3,3-dimethyl-4-pentenoate

A mixture of 2.02 g of 1,1-diethoxy-1- (3-methyl-2-butenyloxy) ethane and 20 mg of phenol was heated at 150-160 ° C for 12 hours while ethanol was developing. The residue was distilled to give 1.12 g (72% yield) of ethyl 3,3-dimethyl-4-pentenoate.

MP: 80-83 ° C / 57 mm Hg.

1,1-Diethoxy-1- (3-methyl-2-butenyloxy) ethane (2.02 g) was heated in the absence of phenol at 150-160 ° C for 20 hours. Distillation gave 1.06 g (68% yield) of ethyl 3,3-dimethyl-4-pentenoate.

M.p .: 87-89 ° C / 62 mmHg.

Example 4

Synthesis of other γ-unsaturated carboxylates

As described in Examples 1-A) and 3, the following γ-unsaturated carboxylates are prepared and have the following characteristics:

A) Ethyl 2,3,3-trimethyl-4-pentenoate

Mp .: 90-92 ° C / 45 mmHg.

Analysis

NMR δ ppm (CCl ₄ ): 6.10-5.55 (dd, 1H), 5.10-4.70 (m, 2H), 4.05 (q, 2H), 2.25 (q, 1H) ), 1.22 (t, 3H), 1.20-0.95 (m, 9H).

B) Ethyl 2-methyl-3-phenyl-4-pentenoate

MP: 104 ^e C / l, 5 mm Hg.

Analysis

NMR δ ppm (CCl ₄ ): 7.12 (bs, 5H), 6.30-4.80 (m, 3H), 4.26-3.20 (m, 3H), 3.00-2.50 (m, 1H), 140-0.78 (m, 6H).

C) Ethyl 2,3-dimethyl-4-pentenoate

Mp .: 90-92 ° C / 65 mmHg.

Analysis

NMR δ ppm (CCl ₄ ): 5.85-5.37 (m, 1H), 5.04-4.78 (Μ, 2H), 4.02 (q, 2H), 2.56-1.98 (tn, 2H), 1.22 (t, 3H), 1.20-0.88 (m, 6H).

D) Methyl 2-ethyl-3,3-dimethyl-4-pentenoate

Mp: 91-94 ° C / 45 mmHg.

Analysis

NMR δ ppm (CCU): 6.10-5.55 (dd, 1H), 5.10-4.70 2H), 3.61 (s, 3H), 2.32-1.98 (m, 1H ), 1.90-1.20 (m, 2H), 1.02 (s, 6H), 0.80 (bt, 3H).

E) Ethyl 3-phenyl-4-pentenoate

Mp: 76-77 ° C / 0.2 mmHg.

F) Ethyl 3-methyl-4-pentenoate

Mp .: 85-89 ° C / 63 mmHg.

G) Ethyl 2,3,3-trimethyl-4-hexenoate

Mp .: 97-99 ° C / 37 mmHg.

H) Ethyl 2,3,3,5-tetramethyl-4-hexenoate

Mp .: 115-117 ° C / 40 mmHg.

I) Ethyl 2,3,3-trimethyl-4-heptenoate

MP: 120-122 ° C / 45 mmHg.

J) Ethyl 2,3,3-trimethyl-4-octenoate

M.p .: 128-131 ° C / 40 mmHg.

K) Methyl 2-ethyl-3,3-dimethyl-4-hexenoate

Mp .: 97-100 ° C / 30 mmHg.

L) Ethyl 3,3-dimethyl-4-hexenoate

Mp .: 103-105 ° C / 57 mm Hg.

M) Ethyl 3,3-dimethyl-4-heptenoate

Mp .: 103-107 ° C / 38 mmHg.

N) Ethyl 3,3-dimethyl-4-octenoate

MP: 114-116 ^e C / 33 Hgmm.

O) Ethyl 3,3,5-trimethyl-4-hexenoate

Mp .: 104 ° C / 45 mm Hg.

P) Ethyl-5-cyclopentyl-3,3-dimethyl-4-pentenoate

MP: 119-123 ^e C / 15 Hgmm.

0) Ethyl 3,3,6-trimethyl-4-hepenoate

Mp .: 90-93 ° C / 30 mmHg.

R) Ethyl 3,3,5-trimethyl-4-heplenoate

MP: 100-104 ^e C / 20 Hgmm.

-4183 162

S) Benzyl 3,3-dimethyl-4-pentenoate

In the same manner as in Example 1-B, 810 mg of benzyl alcohol

1122 mg of ethyl 3,3-dimethyl-4-pentenoate are reacted in the presence of 48 mg of sodium ethylate in 30 ml of toluene. This gave 1.0 g (65% yield) of benzyl 3,3-dimethyl-4-pentenoate.

Mp: 92-98 ° C / 0.1 mmHg.

Analysis using the formula C 1, »H ₁₈ O ₂ :

Calculated: C, 76.49; H, 8.51; Found: C, 76.79; H, 8.25%.

NMR δ ppm (CCl ₄ ): 7.29 (bs, 5H), 5.84 (dd, 1H),

5.05 (s, 2H), 5.05-4.70 (m, 2H), 2.22 (s, 2H), 1.06 (s, 6H).

Claims (2)

Patent claims A process for the preparation of γ-unsaturated carboxylic acid derivatives of the formula I; in the formula R is (1-4C) alkyl, phenyl (1-4C) alkyl or phenoxyphenyl (1-4C) alkyl, R ² and R ³ are each independently hydrogen, C 1-4 alkyl or phenyl, R ^{7 is} hydrogen or C 1-4 alkyl, R ^{4 is} hydrogen, (C 1 -C 6) -alkyl or (C 3 -C 5) -cycloalkyl, and R ^{5 is} hydrogen or (C 1 -C 4) -alkyl, wherein: (z) alkenol of formula (II) wherein R ² , R ³ , R ⁴ and R ⁵ are as defined above, R ^{7 is} -CH ₂ C (OR) _3; condensed orthoester of formula wherein R and ^R7 are as 5 in the presence of an acid catalyst, preferably phenol or C2-C6 aliphatic acid, at a temperature of 20 to 250 ° C, preferably 0.001 to 20% by weight, based on the amount of alkenol, or b) alkenol of formula II wherein R ² , R ³ , R ⁴ and R ⁵ is condensed with the above orthoester R ⁷ -CH ₂ C (OR) ₃ , where R ⁷ and R are present in the presence of an acidic catalyst at a temperature below 120 ° C, and the resulting mixed compound of formula III further reacting the orthoester with the orthoester of R ⁷ -CH ₂ C (OR) _{3 in} the presence of an acidic catalyst at ICO-250 ° C while removing the resulting alcohol, or c) a mixed orthoester of formula III wherein R ² , R ³ , R ⁴ , R ⁵ , R ⁷ and R are as defined above, With an orthoester of 20 R'-CH ₂ C (OR) ₃ in the presence of an acidic catalyst at 100-250 ° C while removing the resulting alcohol; and, if desired, the resulting compound of formula (I) with an alcohol of formula R-OH Wherein R is as defined above but different from the ester component. (Priority: September 9, 1975) 2. The method of claim 1, 30 wherein the starting material is 3-methyl-2-buten-2-ol and ethyl orthoacetate. (Priority: September 10, 1974)