JPS6070193A - Production of piperonal - Google Patents

Abstract

PURPOSE:To produce piperonal at a high yield by electrolyzing isosafrole glycol in an org. solvent or a solvent mixture composed of the org. solvent and water in the presence of a specific electrolyte. CONSTITUTION:The isosafrole glycol expressed by the formula ( I ), the hydroxide, halide and carbonate of an alkali metal, the halide of an alkaline earth metal and other electrolytes are put together with pentane, heptane, octane and other org. solvents into a reaction vessel and are made into an electrolyte. Water is added if necessary to the org. solvent in this case and the isosafrole glycol is incorporated at 0.01-50% concn. into the electrolyte. The electrolyte is so adjusted as to have 0.1-25% concn. An anode and cathode formed of Au, Pt, stainless steel, etc. are dipped in the electrolyte and after electrolysis is performed at 1-100A/cm<2> current density, piperonal is produced at a high yield by solvent extraction, distillation, etc. of the conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing biperonal by oxidative cleavage of insafluor-glycol by electrolytic reaction.

[Technical background]

Piperonal, also known as heliotrobin, is an extremely useful compound industrially as a synthetic intermediate for agricultural chemicals and medicines, in addition to being used as a fragrance.

Conventionally, various methods have been proposed for producing piveronal. However, regarding the method of producing piveronal using insaflorol glycol, which is easier to produce than insaflor, as a raw material, Osamu Okuda [Fragrance Chemistry Comprehension [ID J (January 15, 1970), Koyo Shoten p., 838]
Apart from a simple demonstration of oxidizing insafrole with lead tetraacetate to form biperonal, no literature has been found detailing this production method. Generally, glycols are cleaved to give aldehydes using periodate, lead tetraacetate, or cerium (IV)
) etc. as an oxidizing agent is known. However, methods using these oxidizing agents are not suitable as industrial-scale production methods because handling of the reactants is complicated and production costs are also high. On the other hand, a method for producing aldehydes by oxidative cleavage of glycol using an electrolytic reaction (T.

5hono, J, Am, Chem, 8oc,,
97. (1975) 2546] is known.

However, this miscellaneous text does not cite any examples of application to glycols having aromatic rings that are easily oxidized. That is, there is no report of obtaining an aldehyde by oxidative cleavage of a glycol having an aromatic ring by electrolytic reaction. [Object of the Invention] The purpose of the present invention is to obtain piveronal in high yield by electrolyzing insafrol glycol. shall be.

[Structure of the invention]

The present invention relates to a method for producing biperonal, which comprises electrolyzing insaflorol glycol represented by the formula % in an organic solvent or a mixed solvent of an organic solvent and water in the presence of an electrolyte.

The present inventors have discovered that piveronal can be produced in high yield and high selectivity by applying an electrolytic reaction to the oxidative cleavage of insaflorol glycol, and have completed the present invention.

The present invention relates to a method for producing biveronal having an aldehyde group by electrolyzing insafrol glycol in an organic solvent in the presence of an electrolyte to oxidatively cleave the glycol.

The reaction mechanism in the present invention can be considered separately in the case where a -.rogen compound is used as the electrolyte and the case where an electrolyte other than the -.rogen compound is used. In other words, when a halogen compound is used, it is electrolyzed to produce hyponorrogenic acid or halogen acid, which is presumed to oxidize and cleave insaflorol glycol. When an electrolyte other than the above is used, it can be assumed that the cleavage reaction progresses due to electron transfer from the aromatic ring of insaflor glycol to the anode.

To carry out the present invention, first, the raw material insafrol glycol, an electrolyte, and an organic solvent are charged into a reactor and stirred well to dissolve or mix them. At this time, if the electrolyte is insoluble in the organic solvent, it is dissolved by adding water and mixed well. At least one positive and negative electrode and, if necessary, a reference electrode are attached to the reactor, and electricity is applied for the necessary time while stirring the reaction solution. After the reaction is completed, piveronal is obtained by conventional methods such as extraction with a suitable solvent or distillation.

The starting material of the present invention, insaflor glycol, is
It can be obtained by treating insaflore with hydrogen peroxide, performic acid, or peracetic acid. Electrolytes used in the present invention include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, sodium iodide,
Alkali metal chloride such as sodium bromide, sodium chloride, potassium iodide, potassium bromide, potassium chloride, alkali metal carbonate such as sodium carbonate, sodium bicarbonate, calcium bromide, calcium chloride, bromide Alkaline earth metal chlorides such as magnesium and magnesium chloride, alkali metal or alkaline earth metal hypochlorites such as sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite, odors Examples include quaternary ammonium chloride compounds such as tetramethylammonium chloride, tetramethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium chloride. The amount of electrolyte to be used can range from 1% to saturated solubility in the solution, but 0.0% to saturated solubility.
A value of about 25 parts per chill is practical.

As long as the organic solvent does not inhibit the reaction and allows the reaction to proceed smoothly, it may be used alone or in a mixture of two or more types, but it is necessary that the reaction be uniformly mixed with insafrol glycol. At this time, if the electrolyte is insoluble in the organic solvent used, add an appropriate amount of water to dissolve the electrolyte. However, the organic solvent and water do not necessarily need to mix, but should be stirred thoroughly. It is desirable to make it uniform. Examples of organic solvents include aliphatic or alicyclic hydrocarbons such as pentane, benzene, octane, and cyclohexane, aliphatic alcohols such as methanol, -ethanol, gropanol, and butanol, carbon tetrachloride, chloroform, methyl chloride, Halogenated hydrocarbons such as methylene chloride, ethylene chloride, dichloroethane, chlorobenzene, tetrahydrofuran,
Ethers such as diethylene glycol methyl ether, ketones such as acetone and methyl ethyl ketone, aromatic hydrocarbons such as benzene, toluene, and xylene, or acetonitrile are used.

There is no particular limit to the amount of solvent used, but the amount used ranges from an amount that dissolves insaflor glycol to a concentration of about 50% to an amount that dilutes insaflor glycol to about 0.01%. It is preferable. The reaction temperature may be room temperature, but from the viewpoint of reaction rate etc.
℃ is preferable.

Electrodes used in the present invention include gold, platinum, titanium or nickel plated with gold or platinum, carbon, titanium,
Those commonly used for electrode reactions such as nickel, stainless steel, copper, and lead may be used, and platinum, nickel, stainless steel, carbon, and lead are preferable from the viewpoint of reaction yield and selectivity.

The current density used is in the range of 0.1 to 500 mk/crn2, but is preferably 1 to 100 mA/crn2 from the viewpoint of current efficiency and reaction selectivity. The theoretical amount of electricity for this electrolytic reaction is 2F/m01, but in reality it is 0
．． 05-15 F/mol especially 0.5-6F/m01
It is preferable to energize.

Next, the present invention will be explained by examples.

Example 1 Insaflorol glycol 10 was added to a 30-mm test tube.
Weigh out 0++v (o, s 10 mmol), dissolve it well in a mixed solvent of 6-benzene and 4-part aqueous solution of sodium bicarbonate, and then place this pruned test tube in an oil bath whose temperature is adjusted to 65°C. Two 2×1.5 sub platinum electrodes were attached, and electricity was applied for 3 hours and 3 minutes (4 F/mol) at a constant current of 6 mA/cm. After the electrolysis was completed, the organic layer was transferred to a 50 ml bulb. and evaporate the solvent under reduced pressure.
On the other hand, the water layer is 301n! , and extracted three times with ethyl acetate. The residue in the bulb and the extract were combined and washed with saturated saline. After drying using Glauber's salt, the solvent was distilled off under reduced pressure to obtain 72.7 cm of brownish crystals. This product was purified using a silica gel column with a mixture of n-hexane:ethyl acetate=5=1 to obtain 69.97n9 of white crystals of piveronal. Yield is 91.
This is Section 3. The instrumental analysis values for this product are as follows.

IRCCHC13): 1690.1605.145
0.1260°1120, 1060,955.82Q-1'H-NMR (CD C1s): δ 9.6
8 (s, IH, CHO), 7.31 (d, eL,
J = 8Hz, J = L5Hz.

1H, ArH), 7.29 (d, J = L5Hz
.

1H, ArH), 6.82 (1, J = 8Hz.

1H, ArH), 6.00 (e, 2H, O-CH,
-0) Examples 2 to 12 The same equipment as in Example 1 was used, except that Insaflor Glycol 100■ was used and the electrolyte and organic solvent were changed.
Table 1 shows the results of producing piveronal in the same manner as in Example 1.

〔Effect of the invention〕

According to the present invention, industrially useful piperonal can be economically obtained in high yield from easily available insafrol glycol by electrolysis.

Patent applicant: Takasago Fragrance Industries Co., Ltd. Agent Hiroshi Nakamoto Same as Akira Inoue Douyoshi Mine Katsura a″4 -ra/i〇-

Claims (1)

[Scope of Claims] A method for producing piperonal, which comprises electrolyzing insaflorol glycol represented by the following in an organic solvent or a mixed solvent of an organic solvent and water in the presence of an electrolyte. 2. The electrolyte is an alkali metal hydroxide, a halogenide, a carbonate, an alkaline earth metal halide, an alkali metal or alkaline earth metal hypochlorite, or a quaternary ammonium halogenide. A method for producing biperonal according to claim 1, which is a compound.