JPS6030748B2 - Method for producing 3-alkyl-2-cycloalkene-1-ol acetates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing 3-alkyl-2-cycloalken-1-ol acetates.

More specifically, 3-alkyl-2-cycloalkene-1-ol acetates are produced by electrolytic decarboxylation and acetoxylation of 1-alkyl-2-cycloalkene-1-carboxylic acids in a mixed solvent of acetic acid, tertiary butanol, and triethylamine. Regarding the method. For more information,
A compound represented by 1-alkyl-2-cycloalkene-1-monocarboxylic acid (R represents an alkyl group such as methyl or ethyl).

Also, n indicates a range of 2 to 14) in an electrolyte solution made mainly of acetic acid, tertiary butanol, and triethylamine, diluted with an appropriate organic solvent if necessary, using a platinum electrode. By passing a current at a constant terminal voltage (approximately 30 V) that induces electrolytic decarboxylation without particularly regulating the oxidation potential, the oxidation potential is generally expressed by Tsujiro (R represents an alkyl group such as methyl or ethyl). .

Cyclic allyl alcohol acetate (0) characterized by obtaining 3-alkyl-2-cycloalkene-1-ol acetate m) (n is in the range of 2 to 14)
It concerns a new manufacturing method.

3-alkyl-2-cycloalkene-1 according to the present invention
-All acetates (0) are 3-alkyne-2-sic. It can be used as an important synthetic intermediate in the production of musk fragrances such as alkene-1-one and 3-alkyl-1-cycloalkyl-one. The conventional production methods described in various documents for the compound X related to the present invention are mainly 1-alkyl-1-cyclo.

Oxidation of the allyl position of alkenes using metal oxidizing agents such as selenium dioxide and chromic acid, bromination of the allyl position using N-bromosuccinimide, etc., and substitution reaction of bromine with acetoxyion with silver acetate, etc. be. However, although all of them are polluting reagents, they require expensive reagents, and there are few that provide good synthesis yields. Furthermore, they tend to lack the ability to selectively produce a single product, which poses many problems as an industrial synthesis method. The present inventors have worked hard to solve these problems and research the development of a new synthetic method, and as a result have established a new and highly selective practical method for producing (0). Ta. This sea bream is an acetoxylation method that utilizes the allyl cation species generated in the two-electron oxidative decarboxylation reaction of a cyclic 3,y-unsaturated tertiary carboxylic acid, and selectively produces m) as a single product. It is characterized by tightening.

Conventionally, regarding the anodic oxidation decarboxylation reaction of cyclic 3,-unsaturated carboxylic acids, J. Day. P. UtleyandG,B,
YateS [Jom Misaki lofChe-micaISoc
[ietyPerkin Ro, 395 (1978)] et al. found that as a result of electrolytic decarboxylation of 4-phenyl-2-cyclohexene-1-carboxylic acid in the coexistence of methanol and sodium methoxide, the corresponding methoxy form was mainly produced; It states that positional isomers regarding bonds are mixed. Electrolysis of 3-hexenoic acid has been described by R. F. CanW skin d
, NaSer-ud-Din, C.J., Scott, B.
, C.L., Weedon
calSocietyPerkinl, 2714 (19
[73] et al. have attempted to synthesize dimers in which the double bond has mainly shifted, with a yield of 30 to 40%.

Also, F. M. Ban and R. Bullet [J
oumal of Chemical SMiety
Perkin I, 1773 (1977)] describe that 69% of the corresponding alkoxy form and 12% of the double bond isomer can be obtained by electrolytic decarboxylation of Stobbe half-esters. On the other hand, it is known that even if acetoxylation of 8,y-unsaturated carboxylic acid is attempted by chemical oxidation using lead tetraacetate, a mixture of isomers with double bond movement is produced in addition to the corresponding acetoxy form. [J. Jacques, C. Weidmann day is ffier and A. Day. reau, Bull
．． S. C. Chim. France, 424 (1959
), Chemical A-acts, 54, 2
45 track (1960)]. The conditions for producing the 3-alkyl-2-cycloalken-1-ol acetate compound m) of the present invention are detailed below.

1-alkyl-2-cycloalkene-1-carboxylic acid (1), which is a starting material according to the present invention, is an easily available raw material, and specifically as a compound used in the method of the present invention, R is methyl, ethyl , n-propyl, n-butyl, n-amyl, n-hexyl, isopropyl, isobutyl, isoamyl, isohexyl, and the like. Generally, carbon atoms of 1 to 8 are preferred. In addition, n, which indicates the ring size in the horizontal formula shown in (1), is an alicyclic compound consisting of 2 to 14 methylene groups, specifically 1-methyl-2-cycloheptadecene-1-carpon. acid, 1-methyl-2-cyclohexadecene-1-carboxylic acid, 1-
Methyl-2-cyclobentadecene...1-carboxylic acid, 1
-ethyl-2-cyclobentadecene-1-carboxylic acid,
1-methyl-2-cyclotetradecene-1-carboxylic acid, 1-methyl U2-cyclotridecene-1-carboxylic acid, 1-methyl-2-cyclododecene-1-carboxylic acid,
Examples include 1-n-amyl-2-cyclohepten-1-carboxylic acid, 1-n-amy-2-cyclohexene-1-carboxylic acid, and 1-n-hexy-2-cyclobentene-1-carboxylic acid. These 1-alkyl-2-
Cycloalkene-1-carboxylic acid (1) is added to a mixed solvent consisting of tertiary butanol, triethylamine, and acetic acid, and if necessary, a diluting solvent such as ethyl acetate is added, and (1) is dissolved in the electrolytic solution prepared in this way. , the corresponding acetate body m) can be easily obtained by a simple electrolytic operation in which two platinum plates are immersed in an electrolytic tank filled with this solution, and electrolysis is performed by applying a terminal voltage of about 30 V without using a diaphragm.
This is an innovative method for selectively generating

Specific examples of the lower aliphatic carboxylic acids used in the method of the present invention include formic acid, acetic acid, propionic acid, butyric acid, and isobutyric acid. Acetic acid is preferred in consideration of economical efficiency, product stability, and ease of handling.

The amount of these lower aliphatic carboxylic acids to be used is usually in the range of 2 to 100 P, preferably 10 to 30 P in molar ratio to 1-alkyl-2-cycloalkene-1-carboxylic acid (1), and the initial concentration is To maintain it, it is best to continue electrolysis while replenishing the consumed amount. Secondary and tertiary amines are used as the supporting electrolyte in the electrolysis method of the present invention, specifically triethylamine, diethylamine, and diisof.

Lopylamine, DBU, pyridine, etc. are used. The amount of these supporting electrolytes to be used is 1 to 100 mol per 1 mol of raw material compound (1), but preferably in the range of 2 to 30 mol. In addition, as a co-solvent, any of secondary or tertiary alcohols such as tertiary butyl alcohol, isobutyl alcohol, and inpropyl alcohol is used, preferably 40% V/V, preferably 5% V/V, and 15% V/V. Good to use.

Furthermore, if necessary, lower aliphatic carboxylic acid esters are used as organic solvents for diluting the electrolyte, specifically methyl acetate, ethyl acetate, propyl acetate,
Isopropyl acetate or the like can be used in the required amount.

These diluted solutions can be used in a concentration of 1 to 1M, but preferably in a range of 1.5 to 3 times that of the electrolyte. In the electrolytic acetoxylation reaction according to the present invention, ordinary electrodes for electrolysis are used, and among these, it is preferable to use platinum electrodes. The temperature of the electrolyte used in the present invention is generally maintained at 0 to 100 °C, preferably in the range of 10 to 35 °C.

As the electrolysis method of the present invention, a usual method of current regulation, potential regulation, or a method of carrying out electrolysis while keeping the terminal voltage constant can be adopted.

In both cases, the current density is 10, 20 skin A/
3-alkyl-2 is produced in a high yield by conducting the electrolysis while maintaining it preferably in the range of 20 to 60 hA/mol, and at this time passing an electric current of 50 to 20 hA/mol.
-Cycloalkene-1-ol acetate (0) is obtained. The product can be purified by both distillation and column methods to obtain pure substances. Next, the method of the present invention will be specifically explained using examples. Example 1 1-Methyl-2-cyclobentadecene-1-carboxylic acid (1) 26-9 (0.098 mm
Add 3.5 parts of ethyl acetate, 0.19 parts of tertiary butanol, 1.5 parts of acetic acid, and 436 parts of triethylamine, and stir to make a homogeneous solution.

Attach a magnetic stirrer, a thermometer, and platinum electrodes (1.5 cm x 2) on the 2nd side to adjust the liquid temperature.
Electrolysis was carried out for 3 hours at a terminal voltage of 30 V (with no current density of 36 and 54 mA/) while maintaining the voltage between 5 and 18 qo. After passing an amount of electricity of about 15 m/mol, the solvent was distilled off under reduced pressure and the residue was extracted with ether.

The organic layer was washed once with aqueous sodium bicarbonate solution, twice with aqueous sodium chloride solution, and then dried over K2C03. The crude oil obtained by distilling off the solvent was purified with a silica gel column using hexane and ethyl acetate in a ratio of 5:1 as the eluent, yielding 21.8% of 3-methyl-2-cyclobentadecen-1-ol acetate. 9 (79%
)was gotten. Boiling point 110-11ro/0.0 on. Infrared absorption spectrum 1735 (C:○), 1
670(CniC), 1374, 1242, 1020-
INM old (CDC13) 61.32 (br.s, 24H
:CQ), 1.70(s, fine: CH3), 2.01(s
, Pan; COO day 3), 2.00-2.18 (m, Ga:C
H2C=C), 5.12(d, *IH; J=1 plate Z,
HC=C) Analysis value C, 77.25: day, 11.4
Calculated value as 1C, 8th 3202 C, 77.09;
Day, 11.50 Examples 2 to 5 In Example 1, the electrolyte material, current density, and quantity of electricity are shown in Table 1.
Example 1 was carried out in the same manner as in Example 1, except for the changes shown in .

The results are shown in Table 1. Table 1

Claims (1)

[Claims] 1. In the presence of acetic acid in a solvent mainly containing an organic solvent,
3-alkyl- which is also characterized by electrolytically oxidizing 1-alkyl-2-cycloalkene-1-carboxylic acids (I)
Manufacturing method of 2-cycloalken-1-ol acetates (II) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (However, R is an alkyl group and n is an integer from 2 to 14) 2
A mixed solvent consisting of lower aliphatic carboxylic acids as a solvent, secondary or tertiary aliphatic alcohols having 3 to 6 carbon atoms, and secondary or tertiary amines as a supporting salt,
Claim 1, which uses a mixed solvent prepared by adding lower fatty acid esters as a diluting solvent if necessary.
The method described in section. 3. The method according to claim 1, wherein platinum or an electrode that can be substituted for platinum is used as the electrode for electrolytic oxidation. 4. The method according to claim 1, wherein the electrolytic reaction is carried out at a temperature in the range of 10 to 35°C. 5 As 1-alkyl-2-cycloalkene-1-carboxylic acids, 1-methyl-2-cyclopentadecene-1
-carboxylic acid, 1-methyl-2-cyclododecene-1-
Carboxylic acid, 1-n-amyl-2-cyclohepten-1
-carboxylic acid, 1-n-amyl-2-cyclohexene-
Claim 1 using 1-carboxylic acid or 1-n-hexyl-2-cyclopentene-1-carboxylic acid
The method described in section. 6 Triethylamine as secondary or tertiary amine, 1
,5-diazapicyclo[5.4.0]-5-udecene (
3. The method according to claim 2, which uses either DBU) or pyridine. 7. The method according to claim 2, wherein acetic acid is used as the lower aliphatic carboxylic acid. 8. The method according to claim 2, wherein tertiary butyl alcohol is used as the secondary or tertiary aliphatic alcohol. 9. The method according to claim 2, wherein ethyl acetate is used as the lower fatty acid ester.