JPH0480892B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing diarylketones. More specifically, the present invention relates to a method for producing diaryl ketones such as diaryl ketones and diaryl diketones from diaryliodonium salts. Diaryl ketones and diaryl diketones are used as synthetic intermediates for pharmaceuticals, ultraviolet absorbers, etc. For example, diaryl ketones are usually produced from benzene and benzoyl chloride or benzene and phosgene through a Friedel-Crafts reaction using an aluminum chloride catalyst. It had been. Furthermore, diaryl diketones were synthesized from benzoin and nitric acid through a complicated process. The present inventors have completed the present invention by discovering that diarylketones can be easily obtained by using diaryliodonium salts as starting materials. _That is, the present invention is based on the formula () [Ar _{1 -I} -Ar ₂ ] However, n R's are each a hydrogen atom,
_C1 to _C12 alkyl group, cyclohexyl group, phenyl group, halogenoalkyl group, halogen atom, carboxyl group, alkoxy group or nitro group, which may be the same or different, and n is an integer of 0 to 3. are aryl groups represented by , which may be the same or different, and X is a counter ion inert to the reaction. A diaryliodonium salt represented by Formula () and/or formula () Ar ₃ COAr ₄ ... which is characterized by reacting with carbon monoxide in a solvent in the presence of a reducing metal selected from the group consisting of zinc, copper, tin, mercury and silver. ...() Ar ₃ COCOAr ₄ ...() Here, Ar ₃ and Ar ₄ are the same aryl groups as Ar ₁ or Ar ₂ , and may be the same or different. . In the present invention, a diaryliodonium salt represented by the above formula () in which the aryl group may have a substituent is used as a raw material. An aryl group is a monovalent substituent derived by abstracting one hydrogen atom from the aromatic nucleus of a fused or non-fused aromatic hydrocarbon, and the aromatic hydrocarbon has any substituent. For example, it can be derived from benzene, indane, naphthalene, etc. Also,
The two aryl groups may be the same or different. The diaryliodonium salt of the present invention is a diphenyliodonium salt represented by the following formula and a substituted product thereof. (Here, n R ₄ and m R ₅ are the same or different, and each is a hydrogen atom, C ₁ to
It is a _C12 alkyl group, cyclohexyl group, phenyl group, halogenoalkyl group, halogen atom, carboxyl group, alkoxy group, nitro group or acylamino group, where n and m are integers of 0 to 3. ) Among such diaryliodonium salts, examples of symmetrical diaryliodonium salts in which the aryl groups are the same include diphenyliodonium, ditolyliodonium dicumyliodonium, di(iso-butylphenyl)iodonium,
Di(alkylphenyl)iodonium such as di(t-butylphenyl)iodonium, di(cyclohexylphenyl)iodonium, dibiphenylyliodonium, di(trifluoromethylphenyl)iodonium, etc. , di(halogenophenyl)iodonium such as di(chlorophenyl)iodonium, di(bromophenyl)iodonium, di(alkoxyphenyl) such as di(carboxylphenyl)iodonium, di(methoxyphenyl)iodonium, di(ethoxyphenyl)iodonium ) iodonium, di(nitrophenyl)iodonium, di(acetylaminophenyl)iodonium, and other salts of di(acylaminophenyl)iodonium. Although the explanation has been given using a symmetrical iodonium salt as an example, it is of course possible to use an asymmetrical diaryliodonium salt in which two aryl groups are different. These diaryliodoniums have the above formula ()
As shown in and (), it forms a salt with the counter ion X 2 , but the counter ion X 2 is not essential to the present invention. Therefore, any anion that is inert to the reaction may be used. Usually selected depending on the method of obtaining the iodonium salt, anions of mineral acids such as bisulfate ion, chloride ion, bromide ion, iodine ion and boron tetrafluoride ion, phosphorus hexafluoride ion, arsenic hexafluoride ion , and metal halide ions such as antimony hexafluoride ion. Although these counterions can exchange ions with each other, a more preferred counterion is a halogen ion such as bromide ion. These diaryliodonium halogen salts can be prepared by the methods described in JP-A-53-101331, JP-B-Sho 57-53767, British Patent No. 1114950 and J.
Am.Chem.Soc. 81 , 342 (1959)
It can be produced by the method of Beringer et al.
For example, produced from benzene, toluene, alkylbenzenes such as iso-propylbenzene, iso-butylbenzene, t-butylbenzene, halogenated benzenes such as indane, chlorobenzene, promobenzene, benzoic acid, anisole, nitrobenzene, acetanilide and biphenyl, etc. For example, to produce diphenyliodonium salt from benzene, benzene and potassium iodate (KIO ₃ ) are added and mixed in acetic anhydride, and then a mixture of acetic anhydride and concentrated sulfuric acid is added. is added dropwise and stirred, then a saturated ammonium chloride aqueous solution is added to precipitate the mixture, followed by filtration and recrystallization to obtain diphenyliodonium hydrochloride. In the present invention, the diaryliodonium salt is reacted with carbon monoxide in a solvent in the presence of a transition metal catalyst and a reducing metal to produce a diaryl ketone represented by the formula
Alternatively, a diaryl diketone represented by the formula () is obtained. The reaction formula is as follows. ₂ [ _{Ar 1 -I} -Ar _{2 ]} . Therefore, specifically, the following three types of diaryl ketones are produced from the diaryliodonium salt of formula (). Ar ₁ COAr ₁ Ar ₁ COAr ₂ Ar ₂ COAr ₂ Similarly, three types of diaryl diketones are produced: Ar ₁ COCOAr ₁ , Ar ₁ COCOAr ₂ and Ar ₂ COCOAr ₂ . That is, taking diphenyliodonium salt as an example, benzophenol and diphenyldiketone, which is a 1,2-diketone, are produced. The transition metal catalyst of the present invention is a group element in the periodic table, such as palladium, rhodium,
Examples include ruthenium, platinum, iridium, osmium, nickel, etc., and palladium-based catalysts are particularly preferred. These transition metals can be used as catalysts in various forms. That is, it can be used regardless of its oxidation number or complex. Taking palladium as an example, alumina and activated carbon are supported palladium, halogenated palladium such as palladium chloride, divalent palladium such as palladium salts of lower fatty acids such as palladium oxide, palladium acetate, etc.
Complexes such as bis(dibenzylideneacetone)palladium can also be used. Carbonyl complexes and the like can also be used for rhodium. A reducing metal is used together with the above transition metal.
As this metal, any suitable metal can be used as long as it is a metal capable of reducing the transition metal. For example, one or more metals selected from zinc, copper, tin, mercury, and silver are preferably used. . It may be an alloy. In particular, metal zinc is preferred because of its good yield. The amount of metal used is sufficient to neutralize the counterion of the diaryliodonium salt to be reacted. Furthermore, any solvent can be used as long as it can dissolve even a small amount of the diaryliodonium salt and is an inert solvent that does not participate in the reaction.
For example, in addition to lower alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, ethers such as dimethoxyethane, dioxane, and tetrahydrofuran, various polar solvents such as dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetonitrile are used. You can choose as appropriate. The reaction of the present invention proceeds mildly and quickly, and the reaction temperature and reaction pressure can be appropriately selected depending on the solvent used and the like. That is, the reaction pressure is normally sufficient at normal pressure and there is no need to pressurize the reaction in particular, but it can be pressurized to prevent scattering of carbon monoxide. The reaction temperature should be in the range of 0° to 100°C, but
A reaction temperature of 0 to 500°C is preferred in order to obtain high selectivity. In addition, the reaction time depends on the introduction rate of carbon monoxide, but it is usually 0.5~
3 hours is enough. After the reaction is completed, the target diarylketones are obtained by washing with water, extraction with ether, and distillation or recrystallization. In the reaction of the present invention, as shown in the reaction formula described above, aryl iodide such as iodobenzene is produced as a by-product. Since iodine is expensive, iodobenzene is also expensive, so in order to make the present invention an economical and inexpensive method, it is necessary to consider the use of this by-product iodobenzene. One method of utilizing this iodobenzene is to obtain a diaryliodonium salt from the produced iodobenzene, for example, by the method of Beringer et al. mentioned above or the method for which the present applicant has previously applied for a patent. As described above, if diaryliodonium salt is obtained from the by-produced aryl iodide, the expensive iodine, that is, the aryl iodide, can be recycled and used, so the method of the present invention is economical without loss. This is a practical and inexpensive method. Next, the present invention will be explained in detail with reference to Examples. Example 1 A flask was charged with the solvent shown in Table 1 (10 ml), palladium acetate catalyst (0.1 m mol), diaryliodonium salt (2 m mol), and metal powder (2 m mol), filled with carbon monoxide, and then stirred at room temperature. The reaction was continued until the absorption of carbon monoxide was completed. The absorption of carbon monoxide was completed in 30 to 60 minutes, but stirring was continued for an additional 30 minutes to complete the reaction. After removing the catalyst, the product is separated by distillation and subjected to gas chromatography, IR,
Identified by NMR. Yield was determined by gas chromatography. The results are shown in Table 1. The yield in the table is the molar yield based on the diaryliodonium salt. In the reactions numbered 1 to 16 in Examples, in addition to the products listed in the table, iodonium salt A contained benzene iodide, and iodonium salt B
In the case of the toluene iodide, and in the case of the iodonium salt C, t-butylbenzene iodide was produced as a by-product at a yield of 93 to 100%.

【table】

[Table] Example 2 The reaction was carried out in the same manner as in the experiment No. 1 of Example 1, except that the metal or palladium acetate was changed to those listed in Table 2. The results are in Table 2
Shown below.

【table】

Claims (1)

[Claims] 1 Formula () [Ar ₁ −I −Ar ₂ ]X ... () Here, Ar ₁ and Ar ₂ are the following formula However, n R's are each a hydrogen atom,
_C1 to _C12 alkyl group, cyclohexyl group, phenyl group, halogenoalkyl group, halogen atom, carboxyl group, alkoxy group or nitro group, which may be the same or different, and n is an integer of 0 to 3. are aryl groups represented by , which may be the same or different, and X is a counter ion inert to the reaction. A diaryliodonium salt represented by Formula () and/or formula () Ar ₃ COAr ₄ ... which is characterized by reacting with carbon monoxide in a solvent in the presence of a reducing metal selected from the group consisting of zinc, copper, tin, mercury and silver. ...() Ar ₃ COCOAr ₄ ...() Here, Ar ₃ and Ar ₄ are the same aryl groups as Ar ₁ or Ar ₂ , and may be the same or different. A method for producing diaryl ketones represented by the following. 2. The method for producing diaryl ketones according to claim 1, wherein the transition metal is a palladium-based catalyst.