Bayer Aktiengesellschaft

Bayeraktiengesellschaft

Bernhard Beitzke

Helmut Fiege

Heinz U Blank

Stefan Antons

Gunter Rauchschwalbe

Albrecht Marhold

Karlfried Wedemeyer

Guido Steffan

Nikolaus Muller

Helmut Kraus

Erich Wolters

Gerhard Marzolph

Otto Neuner

Joachim Komoschinski

Wolfgang Eymann

Karl-Wilhelm Henneke

Michael Herzhoff

Volkmar Handschuh

Robert Weitz

Particularly pure di-C.sub.1 -C.sub.4 -alkyl 5-nitro-isophthalates are obtained in good yield and in a simple process by dissolving 5-nitro-isophthalic acid in a mixture of a C.sub.1 -C.sub.4 -alkyl alcohol and a solvent which is miscible or only partially miscible with water, heating in the presence of a strong acid, thus forming a second, aqueous phase, crystallizing out, after the esterification reaction has ended, the di-C.sub.1 -C.sub.4 -alkyl 5-nitro-isophthalate formed from the organic phase by cooling and removing the aqueous phase before or after the di-C.sub.1 -C.sub.4 -alkyl 5-nitro-isophthalate is separated off.

Process for preparing di-C.sub.1 - C.sub.4 -alkyl 5-nitro-isophthalates

N-aryl-N'-alkyl-piperazines are obtained in a particularly simple manner, in good yields and in short reaction times when an aniline is reacted under pressure with an N-alkyl-bishydroxyethyl-amine in the presence of a strong acid.

Process for preparing N-aryl-N'-alkyl-piperazines

2-Halogeno-4,5-difluoro-benzoyl fluorides are obtained in high yields by reacting 2,4-dichloro-5-fluoro-benzoyl halides with potassium fluoride in an aprotic solvent. The 2-halogeno-4,5-difluoro-benzoyl fluorides prepared in this way are particularly suitable as intermediates for the preparation of antibacterial active substances.

Process for the preparation of 2-halogeno-4,5-difluorobenzoyl fluorides

N-arylaminoacrylic acid derivatives are obtained in good yields and in high purities when benzoylacetic acid derivatives are reacted with N-arylimino ethers. The products thus prepared are used, in particular, for the preparation of 4-quinolone-3-carboxylic acid derivatives, which have an outstanding bactericidal action.

Process for the preparation of N-arylaminoacrylic acid derivatives and

Optically active amino alcohols are prepared by reducing optically active amino acids with hydrogen in the presence of ruthenium catalysts.

Process for preparing optically active amino alcohols

Aminomethylene compounds of the formula ##STR1## may advantageously be prepared by reacting C--H-acidic compounds of the formula ##STR2## with formamide acetals of the formula ##STR3## in which the radicals R.sup.1 to R.sup.6 have the meaning given in the description, if the process is carried out in the presence of a secondary amine of the formula ##STR4## in which R.sup.7 and R.sup.8 have the meaning given in the description.

Process for the preparation of aminomethylene compounds

Nitrophenyl alkyl ethers can be advantageously prepared by reacting a nitrophenol with an alkyl halide in water as the reaction medium in such a manner that the nitrophenol is laid before with the water and the alkyl halide and a hydrogen halide-binding compound are then added simultaneously.

Process for the preparation of nitrophenyl alkyl ethers

In the preparation of 3,5-dichloro-.alpha.-methylstyrene by isopropylation of an m/p-dichlorobenzene mixture, isomerization of the resulting alkylation mixture, subsequent side chain bromination of the alkylation mixture and dehydrobromination of the resulting bromination mixture, the improvement which comprises reacting an excess of an m/p-dichlorobenzene mixture which contains at least 50% by weight of m-dichlorobenzene with isopropyl halide, isomerizing the resulting alkylation mixture under pressure in the presence of aluminum chloride until thermodynamic equilibrium has been attained, separating off the isomerized alkylation mixture from the unreacted m/p-dichlorobenzene mixture, and recycling the unreacted mixture for further reaction.

Process for preparing 3,5-dichloro-.alpha.-methylstyrene

The new compound 5,5-dichloro-4,5-dihydro-6-hydroxy-2-trichloromethylpyrimidin-4-one can be prepared by reacting 4,6-dihydroxy-2-methylpyrimidine or chlorinated subsequent stages with a chlorinating agent. 5,5-dichloro-4,5-dihydro-6-hydroxy-2-trichloromethylpyrimidin-4-one can be used as an intermediate for the preparation of 2-trichloromethyl-4,5,6-trichloropyrimidine.

5,5-dichloro-4,5-dihydro-6-hydroxy-2-trichloromethylpyrimidin-4-one

A mixture of an optionally substituted cinnamic acid ester and an optionally substituted .beta.-alkoxy-.beta.-phenyl-propionic acid ester is prepared by reacting an optionally substituted benzaldehyde with an optionally substituted acetic acid ester and an alcoholate in the presence of an alcohol. The reaction can be carried out in a wide temperature range of from -20.degree. C. to +150.degree. C. The ester mixture can be hydrolyzed under acid or alkaline conditions to give optionally substituted cinnamic acid.

Process for the preparation of a mixture of an optionally substituted

A process for the preparation of cinnamic acid is provided by the present invention in which an optionally substituted benzaldehyde and alkali metal salt of carboxylic acid and/or alkali metal (bi) carbonate, as condensing agents, are heated up to a temperature of 100.degree.-220.degree. C. and thereafter there is introduced into the so heated mixture acetic anhydride in at least a stoichiometric amount based upon the amount of optionally substituted benzaldehyde employed. The process can be carried out by heating up a reaction mixture to 100.degree.-220.degree. C. which is free of acetic anhydride or one which contains acetic anhydride but less than a stoichiometric amount thereof based upon the amount of optionally substituted benzaldehyde.

Growing community of inventors

Rosrath, Germany

Bernhard Beitzke