JPS59157047A - Preparation of dehydromuscone - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for preparing muscone, a fragrant component of natural musk in high selectivity in high yield and in high purity, by using a specific organozinc compound as a ring formation agent, subjecting 2,15-hexadecanedione to intramolecular ring formation. CONSTITUTION:1mol 2,15-hexadecanedione shown by the formula I is subjected to intramolecular ring formation in the presence of 1-100mol ring formation agent of an organozinc compound such as ethylzinc iodide, n-prppylzinc bromide, etc. shown by the formula II (y is 0<y<=2; R is alkyl, cycloalkyl, aryl, or these groups containing substituent group; X is halogen, halogenoide) based on the compound shown by the formula I at 20-200 deg.C for 0.5-24hr, to give the desired compounds shown by the formulas IIIa, IIIb and IIIc. The organozinc compound is prepared by reacting an organic halide or organic halogenoid with zinc powder whose surface is modified with copper or an alloy of zinc and copper in a solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing dehydromuscone, which is known as an intermediate necessary for the production of muscone, which is an aromatic component of natural musk, and more specifically, 2,15 - A method for producing dehydromuscone by intramolecular cyclization of hexadecanedione.

Conventional technology 22.5-Hair Gade r Geo, within minutes or 8. village.

As a method for producing dehydromuscone, Tsuji et al. described a method in which 2,15-hexadecanedione is intramolecularly frozen using a specific m-ffi aluminum compound and a tertiary amine in the presence of an inert solvent. (Japanese Unexamined Patent Publication No. 55-85536)0 However, in this method, the activity of the organoaluminum compound used in the method in the condensation of ketones is very strong, so 2.15-
While hexadecanedione is intramolecularly cyclized to convert it into dehydromuscone, a portion of the generated dehydromuscone is also intermolecularly condensed, so there is a limit to the improvement in the yield of the desired dehydromuscone. In addition, in this method, trace amounts of oxygen-containing compounds such as phenol used in the preparation of the organoaluminum compounds or tertiary amines coexisting in the reaction system remain in the resulting dehydromuscone, and these trace impurities are completely removed. Since it is practically not easy to remove them, the above-mentioned oxygen-containing compounds or tertiary amines are mixed in the muscone itself derived from dehydromuscone, which causes deterioration in the aromatic quality of muscone. .

In view of the above-mentioned problems found in conventional methods, the present inventor has developed a method for producing dehydromuscone, which is substantially free of impurities, in high yield by intramolecular cyclization of 2,15-hexadecanedione with high selectivity. As a result of studying possible methods, the present invention has been completed.

Purpose of the Invention Therefore, the present invention provides a method for producing impurity-free dehydromuscone in high yield by employing a specific organozinc compound as a cyclizing agent during intramolecular cyclization of 415-hexadecanedione. The purpose is to provide a way to obtain.

The present invention will be explained in detail below.

Structure of the Invention The structural feature of the present invention is that 2.15-hexadecanedione is prepared by the general formula % in the presence of an inert solvent, where y is a real number represented by 0<y≦2; , R represents an alkyl group, a cycloalkyl group, an aryl group, or a group having a substituent on these groups, and X represents a halogen or a halogenoid. to obtain dehydromuscone.

The intramolecular cyclization reaction according to the present invention is achieved according to the reaction formula shown below.

In the organozinc compound used as a cyclizing agent in the present invention, R in the above general formula is methyl, ethyl, or propyl.

Alkyl groups such as butyl, pentyl and hexyl; cycloalkyl groups such as cyclopentyl and heclohexyl; aryl groups such as phenyl and naphthyl, or alkyl and aryl groups in these groups.

Those with added groups such as alkoxy groups, halogens, etc.
It includes compounds in which X is a halogen such as fluorine, chlorine, bromine, and iodine, or a halogenoid (pseudohalogen) such as cyano, isocyano, cyanato, incyanato, thiocyanato, inthiocyanato, and specific examples thereof include , dimethyl salivary lead, diethylzinc, ethylzinc iodide.

Examples include propyl zinc bromide, methylzinc chloride, phenylzinc cyanide, tolylzinc incyanide, 2-chloroethylzinc thiocyanide, and benzylzinc thiocyanide.

These organic zinc compounds may be present in the reaction system alone or in an associated state, or may further form a complex with the solvent in the reaction system. Moreover, when the above-mentioned organic zinc compound is adjusted by the method described below, y takes various values. This is presumed to be because a plurality of compounds are associated or mixed, and any of them can be used as a cyclizing agent. Also, this and the general formula Zn X2 (in the formula R,
has the same meaning as in the above general formula) may also coexist in the reaction system.

The organic zinc compound used in the present invention is Blai
l of se reagent! For example, by reacting an organic halide or an organic halide with a surface-modified zinc powder or an alloy of zinc and copper in a solvent. It can be prepared by reacting diorganozinc with zinc halide or pseudozinc halide, or by reacting organomagnesium halide with zinc halide or pseudozinc halide.

In the present invention, using the above organozinc compound, 2.15-
For intramolecular cyclization of hexadecanedione, use an inert solvent such as hexane, heptane.

Hydrocarbons such as benzene, toluene, xylene, diethyl ether, tetrahydrofuran, diethers,
In the presence of halogenated hydrocarbons such as carbon tetrachloride, chloroform, and chlorobenzene alone or in mixtures,
The organic zinc compound may be added in an amount of 1 to 100 moles, preferably 3 to 10 moles, relative to 215-hexadecanedione. Incidentally, a wide variety of solvents can be used as long as they are inert. At this time, if the amount of the organozinc compound added is too small, the conversion rate of 2,15-hexadecanedione to dehytromusgon will be low, while if it is too large, it is not economical. , 0.0% of the inert solvent present in the reaction system.
01-30 In the case of heavy views and urban areas, it is best to use 0.1 to 5% by weight; if this amount is too small, the yield of the desired dehydromuscone will be low and impractical; on the other hand, if it is too large, Side reactions occur and the selectivity in the intramolecular cyclization reaction decreases.

The intramolecular cyclization reaction of 2,15-hexadecanedione according to the present invention is carried out at 20 to 200° C. using the above-mentioned organozinc compound in the presence of the above-mentioned organic solvent.

Preferably 0.5 to 2 at a reaction temperature of 50 to 100°C.
This is achieved by carrying out the process for 4 hours, preferably 1 to 10 hours. Note that if the reaction temperature is too low, the reaction will take a long time, and if it is too high, side reactions will occur, which is undesirable.If the reaction time is too short, the reaction rate will decrease, while if it is too high, the selectivity of the reaction will decrease. This is not preferable because it reduces the

By the above reaction, 3-methyl-
2-cyclopentadecen-1-one, 3-methyl-3-
Cyclopentadecen-1-one as well as 3-methylene-cyclopentadecane-1-one are obtained. These dehydromuscones can be converted into muscones by hydrogenation in the presence of a palladium-based catalyst using a known method.

As mentioned above, according to the present invention, 2. Dehydromuscone as an intermediate for muscone can be advantageously produced from i5-hexadecanedione. EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Example 1 Metallic copper was deposited on the surface of the zinc powder by immersing 20.9 g of zinc powder in an aqueous solution of 5 g of copper sulfate dissolved in 20 mA of water, and then thoroughly dried to produce zinc.

Copper powder 1911 was obtained. This zinc, copper powder and toluene i
o o mz, ethyl acetate 5 m, iodine 10 m
Charge A and 20 m of ethyl iodide into a flask,
The reaction was carried out under reflux for 3 hours with thorough stirring to produce ethylzinc iodide. This reaction solution was allowed to stand still to allow unreacted zinc to precipitate, and 26 g of ethylzinc iodide was recovered as a solution.

2.15 Cyclization of hexadecanedione Solution 2 containing ethylzinc iodide obtained above
0 mb, toluene 701 and tetrahydro 7
A flask equipped with a condenser was charged with 20 mA, and the temperature of the liquid in the flask was maintained at 80°C. After 7 cm, 0.254 Ii of 2,15-hexadecanedione was added to 20 m of tetrahydrofuran and 701 m of toluene while stirring. The reaction was carried out while dropping the dissolved solution i 40 an at a rate of 20°C per hour. After this dropping was completed, the resulting reaction solution was washed with diluted hydrochloric acid, and the product was quantitatively analyzed by gas chromatography. As a result, it was confirmed that dehydromuscone was produced in a yield of 80 molti based on 2,15-hexadecanedione before the reaction.

Example 2 Preparation of organozinc compound Thoroughly dehydrated zinc bromide 34II was suspended in tetrahydrone 507an, and n-bromide was prepared with stirring at room temperature.
3 moles of propylmagnesium/! 59 mL of tetrahydrofuran solution was added dropwise and reacted for 30 minutes to produce n-propylzinc bromide. After standing still, n-propylzinc bromide 2711 was obtained as a tetrahydrofuran solution.

20 m of the solution containing n-propylzinc bromide obtained above! was charged with heptane 80771 into a flask equipped with a condenser, the temperature of the liquid in the flask was maintained at 90°C, and 2,15-hexadecanedione 1 was added to this with stirring.
．． Tetrahydro 7 run 10rIL with 016J! and 401 liters of solution dissolved in 30,771 liters of heptane per hour.
The reaction was carried out while dropping at a speed of n. After this dropwise addition was completed, the resulting reaction solution was washed with diluted hydrochloric acid, and the product was quantitatively analyzed by gas chromatography. Dehydromuscone was produced in a yield of 65 molti based on the 15-hexadecanedione used before the reaction. It was confirmed that it was.

Applicant: Japan Mining Co., Ltd. Agent Hirotoyo Miyata

Claims (1)

[Claims] 2.15-hexadecanedione is prepared from the general formula % in the presence of an inert solvent, y is a real number represented by O<y≦2, and R is an alkyl group, cyclo A patented method for producing dehydromuscone that involves intramolecular cyclization using an organozinc compound represented by an alkyl group, an aryl group, or a substituent-containing group, where X represents a halogen or a halogenoid.