JPS61186353A - Production of ketone - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an intermediate for pharmaceuticals and agricultural chemicals, in high yield, suppressing the dehalogenation reaction, by carrying out the catalytic hydrogenation of a specific anthranyl in the presence of a platinum catalyst and a lower alcohol or a hydrated lower alcohol solvent. CONSTITUTION:The objective aromatic ketone of formula II can be produced by the catalytic hydrogenation of the anthranyl of formula I [X is halogen except for F; A is pyridyl, phenyl or p-halogenophenyl (except for F)] in the presence of a platinum catalyst and a lower alcohol or a hydrated lower alcohol solvent. The catalyst is preferably a platinum-carbon catalyst, and the amount of the platinum metal is 0.01-2.0wt%, preferably 0.03-1.0wt% based on the anthranyl.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application The present invention relates to a process for producing aromatic ketones. Specifically, in the anthranyl of the following general formula α), in the formula C, X means a halogen atom excluding fluorine, and A is pyridyl, phenyl or. - or p-halogenophenyl group (excluding fluorine). ] The present invention relates to a method for suppressing the dehalogenation reaction and obtaining high yields in the production of the following general i(m) by catalytic hydrogenation reaction.

(In the formula, X and A are the same as in formula (I)) It is an extremely useful intermediate for

Five-speed II■L A method for producing 2-aminophenyl aryl ketone or 2-aminophenyl pyridyl ketone containing a halogen group in the nucleus is to synthesize it from benbrozoic acid chloride and p-halogenoaniline by Friedel-Zaraft reaction. Methods [Journal, Op, Organic Chemistry (J, O, C)
29, p. 2856, (1962)), a method for reducing the corresponding anthranil with iron powder [Organic Compound Synthesis Method, 20
Volume, page 4], and a catalytic hydrogenation method similar to the method of the present invention in which the reaction is carried out in an ethyl acetate solvent using 10% PD-carbon as a catalyst [Journal of Organic Chemistry (J, O, C, ), Vol. 27, p. 1929 (1962)) and a method of reacting in a lower alcohol solvent using an iron-containing palladium catalyst [Japanese Patent Publication No. 41-223851, etc. are known.

Problem 1 to be solved by the invention: However, in the Friedel-Crafts reaction, which is the conventional method, the yield is extremely low at around 20 cm, and in the maize iron powder reduction method, a large amount of waste water and waste treatment is required. It has drawbacks such as being expensive and cannot be called an industrial manufacturing method.

As an improvement on these methods, a method for producing aromatic ketones by catalytic hydrogenation of the corresponding anthranils using the palladium-based catalyst was developed, but according to the inventors' detailed follow-up experiments, several molecules that cannot be ignored are present. A dehalogenated product was produced, and a decrease in the yield of the desired product was observed. This point can be easily expected from the fact that the specification and examples of the above-mentioned Japanese Patent Publication No. 41-22385 state that it is necessary to stop the reaction as soon as the theoretical amount of hydrogen is absorbed. and
In fact, in additional tests conducted by the present inventors, it was confirmed that hydrogen absorption continued at the theoretical amount without stopping.

In addition, according to the studies conducted by the present inventors, this dechlorination reaction is further accelerated in the presence of water, so it is important to manage the moisture brought in from raw materials and solvents, and even the moisture in solvents that are recovered and reused. It has also become clear that caution is required.

. The present inventors have developed an extremely industrially advantageous method that does not have the above disadvantages.
As a result of intensive studies on a method for producing an aromatic ketone represented by the general formula (n) by catalytic hydrogenation of anthranil represented by the general formula (0), platinum was used as a catalyst in the presence of a lower alcohol solvent.

We have discovered that by using a catalyst, it is possible to produce high-quality aromatic ketones with suppressed dehalogenation products.

In addition, since hydrogen absorption completely stops near the theoretical amount, the end point of the reaction is extremely clear, and this trend has no effect even if a water-containing lower alcohol solvent is used, so a large amount of water is used to wash anthranib. It is an extremely advantageous method that eliminates the need for drying anthranil, simplifies the process, and allows use of hydrous alcohol without any problems.

The raw material used in the present invention, that is, anthranyl represented by general formula (I), can be obtained by a known method of reacting a compound of the following general formula (III) (in which the characters are the same as above) with p-nitrohalogenobenzene. Manufactured by. (For example, see the above-mentioned "organic compound synthesis method.") This first reaction is usually carried out in a lower alcohol and water in the presence of a base such as sodium hydroxide, and in the method of the present invention, the obtained compound of general formula (I) It is not necessarily necessary to isolate and use.

Examples of the platinum catalyst used in the catalytic hydrogenation reaction of the method of the present invention include platinum oxide, platinum catalysts supported on carbon, alumina, etc., and platinum and carbon catalysts are preferred. The amount used is 0 in terms of platinum metal amount compared to anthranyl.
．． The amount may be 0.01 to 2.0% by weight, preferably 0.03 to 1.0% by weight.

Examples of the solvent used in the reaction include lower alcohols such as methanol, ethanol, and propatool, and water-containing alcohols thereof. In particular, the same solvent as the one used in producing the raw material anthranil is preferred, and methanol is most suitable.The reaction temperature is not particularly limited, but is preferably 30 to 60%.
℃ is fine. The reaction pressure is selected to be around normal pressure, and there is no need to increase the pressure.

A more detailed explanation will be given below with reference to Examples.

Example 1 3-Phenyl-5-chloroanthranyl 15 was added to a 300 mJ glass flask equipped with a stirrer, thermometer and condenser.
．． 11 (0,065 mol), methanol 90 g, and 5
0.31 of platinum-carbon (Japan Engelhard Co., Ltd.) was charged. After replacing the system with nitrogen and then with hydrogen, the water column was 200
The reaction was carried out at a temperature of 40-45° C. under micropressure maintained at ˜300 sn. After 120 minutes of reaction, hydrogen was 146ONrn.
It stopped when 1 was absorbed. After aging for 20 minutes (no hydrogen absorption was observed during this period), the system was cooled, the system was purged with nitrogen, and the catalyst was filtered. After concentrating solution F, the residue 2-amino-5-
Chlorbenzophenone 15.1! I got i. When this product was analyzed by liquid chromatography, no anthranil was detected, and the target product was 99.4%.
(Theoretical yield: 99.7%) The amount of 2-aminobenzophenone, which is the dechlorinated by-product, was 0.2%. ◎ Example 2 The procedure was carried out except that 10ml of water was added to 90ml of methanol used in Example 1. The preparation and reaction treatment were carried out in the same manner as in Example 1. The reaction stopped when 146ON+a/ of hydrogen was absorbed. As a result of analysis, 2-amino-5-chlorobenzophenone was obtained with a theoretical yield of 99.6%.

Comparative Example 1 A sample was prepared in the same manner as in Example 1 except that 5% palladium-carbon was used instead of 5% palladium-carbon. The reaction was stopped when 146 ONm/hydrogen was absorbed. Immediately after cooling, the system was purged with nitrogen and the catalyst was filtered. After concentrating the p solution, a residue of 15.19% was obtained.

When this substance was analyzed by liquid chromatography,
The unreacted material was 15.1%, the target product was 60.2% (theoretical yield 71, Oti), and the by-product contained 5.2% 2-amino-benzophenone, which is the dechlorinated product. .

Comparative Example 2 The preparation and reaction were carried out in the same manner as in Example 2 except that 5% platinum-carbon was replaced by 5% palladium-carbon. The reaction is hydrogen absorption amount 14
The test was stopped at 6ON- and treated and analyzed in the same manner as in Example 2. As a result, the desired product ss in the residue was only 2-amino-5-chlorobenzophenone at 7% (theoretical yield 65.8%), and 2-amino-benzophenone was contained at 11.2%. It was◎

Claims (3)

[Claims] (1) Anthranil represented by the following general formula (I),
▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, X means a halogen atom excluding fluorine, and A means pyridyl, phenyl, or o- or p-halogen phenyl group (excluding fluorine) . ] General formula (II) characterized by catalytic hydrogenation in the presence of a platinum catalyst and a lower alcohol or a hydrous lower alcohol solvent ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, X and A are A method for producing an aromatic ketone represented by the formula (I). (2) The method according to claim (I), wherein the lower alcohol is methanol. (3) The method according to claim (1), wherein the compound of general formula (II) is 2-amino-5-chlorobenzophenone.