DE2257674A1 - Aromatic ketones prepn - by acylation of aromatics using nitroaromatic sulphonic acid catalysts - Google Patents

Abstract

Prepn. of aromatic ketones is by acylation of suitable aromatic cpds. with acid chlorides or anhydrides opt. under pressure, using as catalyst a mono- or bi-cyclic aromatic sulphonic acid carrying is not 2 NO2 pgs. and cpds. of formula (I): R1-C(O)-R2 (where R1 is aryl or aliphatic and R2 is aromatic or heterocyclic carrying 2-4 gps. 1, 2 or 3 of which are NO2. Nitrobenzophenones are inters for plasticisers and dyes.

Description

Process for the production of aromatic ketones Addition to patent . ... ... (patent application P 22 01 208.4).

Subject of the main patent. ... ..0 (patent application P 22 01 208.4) is a process for the production of aromatic ketones by converting im aromatic nucleus, aromatic compounds which can be acylated with carboxylic acid chlorides or carboxylic anhydrides in the presence of a catalyst at normal or elevated Temperature and normal or elevated pressure, with the reaction with catalytic Amounts of a mono- or binuclear aromatic containing at least 2 nitro groups Sulfonic acid or a derivative carries out that under the reaction conditions passes into such a sulfonic acid, the aromatic residue being the sulfonic acid still further substituents which are inert under the reaction conditions, preferably can wear in positions in which the acidity of the sulfonic acid group increases is, and where at least 2 nitro groups in the positions para and / or ortho are bound to the sulfonic acid group.

It has now been found that the process of the main patent continues Can be designed if the acylatable compound is at least one disubstituted in the core aromatic compound, among the substituents on the nucleus at least one Nitro group is used.

In the case of the use of 4-nitrol, 3-resorcinol dimethyl ether and o ° toluene chloride, the reaction can be represented by the following formulas: Surprisingly, the process according to the invention can also be used to acylate compounds which have nitro groups in their core, and carboxylic acid anhydrides and carboxylic acid chlorides also substituted by nitro groups also come into consideration as aylating agents. The resulting nitrobenzophenones could previously by the usual Friedel-Crafts process, for example

with aluminum chloride, not or only with low yield will.

The range of variation of the new process is practically the same as the Friedel-Crafts synthesis. The acylatable compound carries in the core at least 2, preferably 2, 3 or 4 substituents, of which at least and preferably one Substituent is a nitro group. Accordingly, aromatic compounds which can be acylated in the nucleus can be used Compounds in addition to preferably a nitro group, preferably by lower alkyl groups, in particular with 1 to 4 carbon atoms, halogen, preferably chlorine, cyano, Alkoxy groups, in particular with 1 to 4 carbon atoms> cycloalkyl groups, in particular cyclohexyl or cyclopentyl groups, carbalkoxy groups, in particular with 2 to 4 carbon atoms, trifluoromethyl groups or alkyl mercapto groups, in particular with 1 to 4 carbon atoms, substituted aromatics are used. Partially hydrogenated polynuclear systems, e.g. with an aromatic one, also come and a cycloaliphatic core, contemplated. The following are to be mentioned in detail: m-nitro-toluene, -xylenes, -ethylbenzene, 5-nitro, l-methyl-3-phenylindane; nitro-anisole, o-nitro-resor 0'd methyl ether, 5-nitro-8-methoxy-tetralin. Aromatic compounds are considered to be here also the Friedel-rFts reaction accessible heterocycles such as thiophene, furan or indoles understood.

Aromatic acylating agents are suitable for the new process or aliphatic carboxylic acid anhydrides and preferably carboxylic acid chlorides. the Acyl radicals can be unsubstituted or substituted, for example by lower Alkyl, e.g. with 1 to 4 carbon atoms, halogen, especially chlorine, alkoxy, e.g. with 1 to 4 carbon atoms, cyano, alkoxycarbonyl, e.g. with 2 to 4 carbon atoms or acyl, e.g. with 2 to 4 carbon atoms, preferably also by nitro. in the some of them are: acetic anhydride, phthalic anhydride, acetyl chloride, pivalic acid chloride, Ethylhexanoic acid chloride, benzoyl chloride, o, m, p-toluic acid chloride, o, m, p-nitrobenzoyl chloride, Terephthalyl dichloride, isophthalic acid dichloride or l-nitroanthraquinone-2-carboxylic acid chlori Otherwise, the process is carried out under the conditions of the process according to the main patent carried out, in particular with reference to catalytically active sulfonic acids, amount of catalyst, temperature range, quantitative ratio of the reaction pa- <ner, if appropriate solvent used, reaction conditions.

The aromatic ketones obtainable according to the invention are valuable intermediates for the preparation of dyes and pesticides. Substances of the formula are advantageously suitable wherein R1 is an aromatic or aliphatic radical and R2 is an aromatic or heterocyclic radical which bears 2, 3 or 4 substituents on the aromatic ring adjacent to the carbonyl group, one of which is advantageously a nitro group. Substances of the formula are preferred where R3 denotes a nitro group, the individual radicals R4, R5 and R6 are identical or different and each denotes a chlorine atom, a cyano group, an alkoxy group, a cycloalkyl group, a carbalkoxy group, an alkyl mercapto group, an alkyl group, a trifluoromethyl group, in addition R5 also denotes a Can denote hydrogen atom, R6 can also denote a hydrogen atom, a benzyl group, a phenoxy group.

The parts given in the following examples are parts by weight; Parts of space relate to parts by weight like the liter to the kilogram.

Example 1 36.8 parts of nitroresorcinol dimethyl ether, 107.5 parts of o-toluic acid chloride and 0.8 parts of 2,4 »6-TrinltrobenzenesulfonsKure are together for 5 hours at 1500C heated. After cooling to room temperature, the mixture is suctioned off and the Filter well washed with 200 parts of cold ethyl alcohol. 46.0 parts (74 ffi of theory) 2-methylphenyl-2 ', 4'-dlmethoxy-5'-nitrophenyl-ketone of melting point 174 to 177 ° C.

Example 2 75 parts of 4-nitroanisole, 211.5 parts of benzoyl chloride and 4 parts of 2,4,6-trinitrobenzenesulfonic acid are heated together at 170 ° C. for 5 hours heated. After cooling, it is extracted several times with petroleum ether and the oily The residue crystallized from ethanol. 67 parts of 2-methoxy-5-nitrophenyl-phenyl ketone are obtained with m.p. (ethanol) 125 to 1280C.

Example 3 54.9 parts of nitroresorcinol dimethyl ether, 127.4 parts of benzoyl chloride and 0.8 parts of 2,4,6-trinitrobenzenesulfonic acid are heated to 1800C for 6 hours. After cooling, the mixture is filtered off with suction and washed with petroleum ether. Man receives 69.4 parts of 2,4-dimethoxy-5-nitrophenyl-phenyl ketone with melting point (ethanol) 149 bis 1520C.

Claims (4)

Claims 1. Further development of the process for the production of aromatic Ketones by reacting aromatic compounds that can be acylated in the aromatic nucleus with carboxylic acid chlorides or carboxylic acid anhydrides in the presence of a catalyst at normal or elevated temperature and normal or elevated pressure where one the reaction with catalytic amounts of at least 2 nitro groups containing carries out mono- or binuclear aromatic sulfonic acid or a derivative, which passes into such a sulfonic acid under the reaction conditions, the aromatic remainder of the sulfonic acid still further inert under the reaction conditions Can carry substituents, preferably in positions in which the acidity the sulfonic acid group is increased, and at least two nitro groups in the Positions para and / or ortho to the sulfonic acid group are attached, according to patent . ... ... (patent application P 22 01 208.4), characterized in that the acylatable Compound an aromatic compound which is at least disubstituted in the nucleus, among at least one of whose substituents on the nucleus is a nitro group is used. 2. The method according to claim 1, characterized in that the Implementation in the presence of a nitroarylsulfonic acid in which the aromatic The remainder in addition to two nitro groups as substituents which are inert under the reaction conditions carries one or more of the groups nitro, trifluoromethyl, cyano or methylsulfonyl. substances of the formula wherein R1 is an aromatic or aliphatic radical and R2 is an aromatic or heterocyclic radical which bears 2, 3 or 4 substituents on the ring of the mononuclear or polynuclear radical adjacent to the carbonyl group, of which one, 2 or 3 substituents are nitro groups. 4. Substances of the formula where R3 denotes a nitro group, the individual radicals R4> R5 and R6 are identical or different and each denotes a nitro group, a chlorate, a hydroxyl group, a cyano group, an alkoxy group, a cycloalkyl group, a carbalkoxy group, an alkylmercapto group, an alkyl group, a trifluoromethyl group , in addition R5 can also denote a hydrogen atom> R6 can also denote a hydrogen atom, a benzyl group, a phenoxy group, a phenylene ring fused to the aromatic nucleus.