JPS61191645A - Production of oxophorone - Google Patents

Abstract

PURPOSE:To obtain oxophorone, in high efficiency and selectivity, by oxidizing alpha-isophorone with oxygen in the presence of phosphomolybdic acid or silicomolybdic acid and copresence of an alkali metal compound or an aromatic amine. CONSTITUTION:The objective compound of formula II useful as an intermediate for vitamin E, tobacco flavor or carotinoid such as rhodoxanthin, etc. economically from an easily available raw material, by oxidizing alpha-isophorone of formula I with oxygen at room temperature -130 deg.C, preferably at 70-110 deg.C, preferably in the absence of solvent, in the presence of phosphomolybdic acid or silicomolybdic acid, a nd in the copresence of an alkali metal salt such as bicarbonate, carbonate, acetate, oxide or hydroxide of Li, Na, K, Cs or Rb, or an aromatic amine such as pyrazine, triazine, 4,4'-dipyridyl, triphenylamine, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Related and more specifically, a method of preparing α-isophorone in the presence of phosphomolybdic acid or cricosoripdic acid in the presence of an alkali metal compound or an aromatic amine. 〇〇 [Industrial Application Field] Ogisophon a obtained by the present invention is a synthetic intermediate of trimethyl-p-hyde mouth-feeding product made from a raw material for the synthesis of vitamin B (see West German Patent Publication No. 2646176), and a tobacco flavoring material. Manufacturing raw materials (U.S. Patent No. 4,477,6854, Special Publication No. 1983)
-29279 and JP-A-59-4589.3)
It is a compound that is widely used as a raw material for the synthesis of carotenoids such as rhodochitin tenen.

[Conventional technology]

Conventionally, methods for producing oxophorone include (a) β
- A method of oxidizing isophorone with oxygen in the presence of a metal catalyst or a base catalyst (see French Patent No. 2335486, West German Patent Publication No. 2515304, West German Patent No. 2457157, etc.), (b) α-isophorone in the presence of a vanadium catalyst, A method of gas phase oxygen oxidation (see JP-A-50-93947), a method of oxidizing V-α-isophorone with t-butylhydroperoquine in the presence of a palladium catalyst (
Murahashi8,,Chem,Lett,,19
83.1081) and 2) A method of oxidizing α-isophorone with oxygen in the presence of phosphomolybdic acid or silicomolybdic acid (see Japanese Patent Publication No. 55-3L No. 696) is known.

[Interlayer points solved by the invention]

However, in method (k)! - Isophorone must be synthesized by isomerization of α-isophorone, and β-isophorone has the disadvantage of being much more unstable to acids and bases than α-isophorone. The method (b) has the disadvantage that the selectivity for oxophorone is low and that 5,5-dimethyl-3-formylfucrohex-2-en-1-one is produced as a multi-fK by-product. The method (/→) has the drawback that the reaction efficiency is poor and an expensive oxidizing agent must be used.The method (2) also has the drawback that the selectivity for oxophorone is low.

As a result of studies aimed at overcoming the conventional drawbacks, the present inventors discovered a method for producing oxophorone efficiently and highly selectively, and completed the present invention.

[Summary of the invention]

The present invention involves producing oxophorone by oxidizing α-isophorone with oxygen in the presence of phosphomolybdenum #R or silicomolybdic acid and an alkali metal compound or aromatic amine.

α-isophorone, which is the raw material for the present invention, is a compound that is easily available industrially. Further, as the oxygen, oxygen gas alone or oxygen gas diluted with air or an inert gas can be used.

The present invention requires that the reaction be carried out in the coexistence of phosphomolybdic acid or silicomolybdic acid and an alkali metal compound or aromatic amine. The amount of phosphomolybdic acid or silicomolybdic acid used is
A so-called contact amount of 1% by weight or less is sufficient.

As the alkali metal compound, hydrogen carbonate, carbonate, acetate, metal oxide, metal hydroxide, etc. of lithium, sodium, potassium, cesium, or rubidium can be used.

Aromatic amines include bifudine, trianne, 4141
Examples include -dipyridyl and triphenylamine. The amount of alkali metal compound used for phosphomolybdic acid or silicomolybdic acid is 4 equivalents or less,
It is preferably about 1 equivalent, and the amount of aromatic amine used is arbitrarily determined depending on the catalyst, but is usually 4 equivalents or less, preferably 1/2 equivalent or less.

The reaction is preferably carried out in an anhydrous medium and proceeds smoothly at a temperature of 1M to 130°C, preferably 70 to 11°C.

The present invention will be explained in detail below by way of examples.

Comparative Example 1 Phosphomolybdenum fi (HsPMo 1204o, 20
mg) was dissolved and stirred at 100°C in an oxygen atmosphere for 8 hours. 1, 2, 4.5 as internal staff IA after reaction completion
-Nato-2-methylbenzene (DexV) was used for analysis by gas chromatography. As a result, unreacted inholon (619-9 recovery rate 31%, conversion rate 69%),
3,5.5-) Rimetelcyclohe-2-2-1.
4-Gio 7 (O+Soho a7, 1.LJg, 45.5%,
Jd rate 65,8ts) and 3-formyl-5,5-dimethylcyclo to 2-2-2-1-one (80~, 3.6
and selectivity 5.2).

Analysis conditions 8himadzu GAS C0 visit HC-38F C-38F8hi CHK)
83% MGA / Diasolid Ll, 2m1
000 821jc9/wound retention time Isophorone 1.25ml1n Oxophorone 1.90mln Aldehyde 3゜65mln Internal standard (Detamer Vn) 0.58bloodnFurthermore, the reaction mixture diluted with dichloromethane was added to saturated sodium bicarbonate IJ.
- Washed sequentially with rum water solution and saturated saline solution, and dried on anhydrous sulfuric acid magnek A.

After removing the solvent, oxophorone was isolated by subjecting it to silica gel column chromatography and eluting with dichloromethane.

BP 115-118℃/37mm)
ig(lit, He1v, Chsm, Acta,
, 3'9°2041 (1956) 92-94'Q/
11 mm14g) NM几(CDCj,)δ: 6,48 (d, J=
1.5) 1g.

IH) @pah, 2.63(s, 2H), 2
．． LIL) (d, J=1.5Hz, 3H), 1.11(
s.

6H) pP scolding + Mass m/z (%) 152 (M, 39), 9
6 (91).

68 (IIJU).

3-formyl-5,5-dumenalcyclohex-2-en-1-one NMle (CDCI,) δ: 1,08 (s, IH), 2.
38(s, 41(), 6.50(s, 18), 9.85
(s, IH).

IR (1iy, film) y 1698, 1686
cm −+ Massm/z (%) 152 (M, 39), 109
(14,5).

96 (89), 81 (14), 68 (100).

67(35).

Comparative Example 2 Suag silicomolybdate (i (48iMo, 21.+48.
0.0274 mmol) in an oxygen atmosphere, IU
L)'Q was stirred for 8 hours.

After the reaction was completed, 1,2,4.5-tetramethylbenzene was added as a tfBI standard and diluted with dichloromethane.
When analyzed and quantified by gas chromatography, the reaction mixture contained unreacted inphorondehyde (223 in., 3 in.
．． 9% (47.7% selected 1).

Example 1 Isophorone (5g, 36.2mm0), phosphomolyphidic acid (50Jl, L), 027mmol) and 4,4'-dipyridyl (2ap, 0.L) as an additive.
13 mmol l) was dissolved under an oxygen atmosphere for 10
The mixture was stirred at 0'Q for 19 hours. After the reaction was completed, the reactants were analyzed and quantified under the conditions shown in Example 1, and the results were as follows: unreacted isophorone (3.14 g, conversion rate 37.3%), oxophorone (1.96 g, 35.7%). , selection rate 95.7ch)
and aldehyde (132 Da, 1.8%, selectivity q, 3
h).

Examples 2 and 3 Sodium carbonate A (1,5ap, 0.014 mmol) or triphenylamine (6,5j11il+, 13.0
The reaction scale and reaction temperature were the same as in Example 1, except that 27 mmol) was used, and the reaction product was analyzed under the conditions shown in Comparative Example 1.

Table 1 The parentheses in the column of yield indicate selectivity. Examples 4 to 7 A solution of isophorone containing triphenylamine (5 g, 36.2 mmol) described in the table below was prepared, and glycomolybdic acid (50 mmol) was prepared. ~, L), 0274 mmol
) was dissolved and 10 L) was stirred at ℃ for 8 hours. The analytical quantification of the reaction mixture was carried out in the same manner as in the previous example, and the results of each reaction are summarized in Table 2.

Ebisu 2

Claims (1)

[Claims] (1) A method for producing oxophorone, which comprises oxidizing α-isophorone with oxygen in the presence of phosphomolybdic acid or silicomolybdic acid to produce oxophorone in the presence of an alkali metal compound or an aromatic amine. .