JPS58167537A - Preparation of 2,6,6-trimethyl-4-oxo-2-cyclohexenylidene acetaldehyde - Google Patents

Abstract

PURPOSE:To prepare the titled compound in high yield and purity, in one step, by using 4-(2-butenylidene)-3,5,5-trimethyl-2-cyclohexen-1-one as a raw material, contacting the raw material with ozone in a solvent, and treating the product with a reagent for decomposing the ozonide. CONSTITUTION:4-(2-Butenylidene)-3,5,5-trimethyl-2-cyclohexen-1-one of formulaI(wavy line is a bond of transor cis isomer) is used as a raw material. The compound is brought into contact with ozone in the presence of an inert organic solvent (e.g. methanol, pentane, etc.), and then treated with an ozonide-decomposition reagent to obtain 2,6,6-trimethyl-4-oxo-2-cyclohexenylidene acetaldehyde of formula II. The compound of formulaIcan be prepared by (1) isomerizing the easily and economically available 3,5,5-trimethylene-2-cyclohexen-1-one, (2) silylating the product to obtain the compound of formula III, (3) condensing the compound with the compound of formula IV, and finally (4) dehydrating the resultant compound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides 2.6.6-)dimethyl-4-oxo-2-cyclohexenylidene acetaldehyde, which is known as one of the important aroma components of tobacco, in a shortened process and The present invention relates to a new manufacturing method that can be industrially advantageously produced with easy operation, high yield, and high purity.

More specifically, the present invention provides 4-(2-putenylidene)-3,5 represented by the following formula (2), where the wavy line indicates the presence of trans and/or cis isomer bonds.

5-trimethyl-2-cyclohexen-1-one is brought into contact with ozone in the presence of an inert organic solvent, and then treated with an ocinide dispersing reagent.
] However, in the formula, the wavy line indicates the presence of trans and/or cis isomer bond.
- A method for producing Schiff 9 hexenylidene acetaldehyde.

The compound 2,6.6-)rifthyl-4-oxetose-cyclohexenylidene acetaldehyde of the above formula (]) is a compound isolated from tobacco concentrate, and is one of the important aroma components of tobacco. It has a high value and significantly enhances the aroma as a base material for preparing tobacco flavorings.

Conventionally, regarding the synthesis of 2,6,6-)rifthyl-4-oxo-2-cyclohexenylidene represented by the formula (11), for example, C,A 52 P12905h (Ll
, S, P, Kawasugi 27, 4811 describes a method for synthesizing the above compound according to the following process diagram (1).

The above conventional proposals require reaction reagents that are disadvantageous in terms of operation, require multiple steps that are disadvantageous, and require complicated operations.
It has disadvantages or defects such as low yield, and is not suitable for industrial implementation.

The present inventors have conducted research in order to overcome the disadvantages and defects of the conventional methods as described above and to provide an improved manufacturing method that can produce the compound of the above formula (1%).

As a result, for example, it was synthesized in three steps from inexpensive and easily available 3.5.5-)rimethylene-2-cyclohexen-1-one by the method already proposed by the present inventors (% 113729/1983). The above formula (2) compound 4-(2-butenylidene)-3,5,5-)rifthyl-
It has been discovered that the compound of formula (11) can be produced industrially advantageously using 2-cyclohexen-1-one as a starting material, easily and with high yield and purity in just one step.

Therefore, an object of the present invention is to provide a new method for producing the formula (112,6,6-1-limethyl-4-oxo-2-cyclohexenylideneacetaldehyde).

The above objects and many other objects and advantages of the present invention will become more apparent from the following description.

The production of the compound of formula (1) of the present invention, including the process of producing the compound of formula (2) described in detail in JP-A-56-113729, is illustrated as follows. can be shown.

The compound of the above formula (2), in which the wavy line C indicates the presence of trans and cis isomer bonds, can also be produced by other known methods, such as Acta Chem, 5cond,
26°2573 (19721; He1v, Chi
m, Acta.

57, 2087 (19741; J, Am, Chem
.

Soc, 97.4018 (1975); Bull.

Chem, Soc, Jpn, 52.1233 (197
9), etc., but it is advantageous to employ the method disclosed in JP-A-56-113729.

According to the method of the present invention, the known compound of formula (2), which can be obtained by the method exemplified above, is brought into contact with ozone in the presence of an inert organic solvent, and then treated with an ocinide decomposition reagent. , the compound of formula (1) can be easily produced.

The contact between the compound of formula (21) and the ozodione is preferably carried out under low temperature conditions in the presence of an inert organic solvent, e.g.
Examples include a temperature of about -4° C. to about -40° C. and a contact treatment time of about 0.5 to about 2 hours. Cough contact treatment can also be carried out in the presence of a base such as pyridine. Examples of inert organic solvents that may be used include alcoholic solvents such as methanol, ethanol, etc., hydrocarbon solvents such as pentane, hexane, etc., ester solvents such as ethyl acetate, halogenated solvents such as methylene chloride, etc. Examples include hydrocarbon solvents, organic acid solvents such as acetic acid, ether solvents such as diethyl ether, and appropriate combinations of these solvents. There are no particular restrictions on the amount of such an inert organic solvent to be used, and it can be selected as appropriate; The amount of ozone to be used can also be selected as appropriate; for example, it can be used in an amount of about 1 to about 1.5 times the amount of the compound of formula (21).

The compound of formula (21) is brought into contact with ozone in the presence of an inert organic solvent as described above, and then further treated with an ocinide decomposition reagent. Examples of ocinide decomposition reagents used in this treatment include triphenylphosphine, Examples include dimethyl sulfide, pyridium chlorochromate, gyridium diclonate, a dilute sulfuric acid aqueous solution of chromium trioxide, etc. The amount to be used can be selected as appropriate, but for example, about 1. An example of an amount used is about 5 to about 10 times the mole.

The above treatment does not require separating the ocinide formed by the contact treatment with ozone, and can be carried out by adding a reagent as exemplified above to the ozone contact treatment system. The treatment temperature can be selected as appropriate, and examples include temperature loss or room temperature of the system subjected to contact treatment with ozone. Further, the processing time may be about 30 minutes to FJ5 hours, for example.

Hereinafter, an example of implementing the method of the present invention will be shown by way of example.

Example 1 2.6.6-Dolimethyl-4-oxo-2-cyclohexenylidene acetaldehyde production 4-(2-putenylidene)-3,5,5-1-limethyl-
2-Cyclohexen-1-one9. ! IM (50mm
120 t of methylene chloride and 1.5 f of pyridine were charged, and 5 Q mmnl of ozone was bubbled at -60°C. After the reaction, 26.2% of triphenylphosphine was added to the reaction solution.
f (100 mm and 1 liter was processed, and after raising the reaction temperature to room temperature, it was stirred for 1 hour [7.

After recovering the solvent, the crude product was purified by silica gel column chromatography (ether-hexane) to obtain 6.3 f of 2,6,6-dolimethyl-4-oxo-2-cyclohexenylidene acetaldehyde (mixture of cis and trans) (yield 71 hits).

1R: 1650.1565 cm-'MS<70eV)m/e; 17B(M), 163.1
50.131.135.93.91゜(1 other person)

Claims (1)

[Claims] 1. 4-(2-putenylidene I-3,5゜5-
The following formula (1) is characterized in that trimethyl-2-cyclohexen-1-one is brought into contact with ozone in the presence of an inert organic solvent, and then treated with an ocinide decomposition reagent. / or 2,6,6-drimethyl-4-okino 2, which shows the presence of a cis isomer bond.
- A method for producing cyclohexenylidene acetaldehyde.