Basf Aktiengesellschaft

Erich Fretschner

Hans Rupert Merkle

Hanspeter Hansen

Bernhard Zipperer

Karl Siegfried Brenner

Knut Koob

Anne Van Gastel

Helmut Fr&ouml;hlich

Klaus Herbig

Kurt Benz

Albrecht M&uuml;ller

Otto W&ouml;rz

The present invention relates to a process for preparing 1-substituted 5-chloro-4-methylpyrazoles of the general formula Iwith the meaning for R stated in claim, in which a 4-methylpyrazole of the formula IIis reacted with chlorine, the resulting mixture of monochlorinated and dichlorinated product is fractionated by distillation, and subsequently the dichlorinated compound is dehalogenated to compound II and returned to the reaction with chlorine.

Method for producing 1 substituted 5-chloro-4 methly pyrazoles

Method for producing 4-amino-5-chloro-1-phenyl pyridazinone-(6)

Method for producing N-substituted 2-pyrazoline-5-one

A process for preparing 3-isopropyl-1H-2,1,3-benzothiadiazin-4 (3H)-one 2,2-dioxide (I) or a salt of I

Method for the production of 3-isopropyl-1H-2, 1,3-benzothiadiazine-4 (3H)-one-2,2-dioxide

Pyrazole derivatives are prepared by reacting carbonyl compounds R,&mdash;C(O)&mdash;CH(R,)&mdash;CH,R,with hydrazine, its hydrate or its salts in 30 to 100% by weight sulfuric acid in the presence of catalytic amounts of iodine or of an iodine compound.

Method for producing substituted pyrazoles

Process for preparing solid, free-flowing water-soluble salts of

Method of preparing 1,2-dimethyl-3,5-diarylpyrazolium methylsulfates

Process for preparing N-substituted pyrazoles

Preparation of optically active 2-halopropionic acids

Preparation of 3,5-diarylpyrazoles

Preparation of pyrazole and its derivatives

3-Methylpyrazole and its derivatives are prepared by reacting butenediols or ethynylalkylcarbinols or their acylates in 30-100% by weight sulfuric acid with unsubstituted or substituted hydrazine or its salts in the presence of catalytic amounts of iodine or an iodine compound.

Preparation of 3-methylpyrazole

Pyrazole and its derivatives are prepared by dehydrogenating 2-pyrazoline or its derivatives by a process in which the reaction is carried out using sulfuric acid in the presence of iodine or of an iodine compound at from 50.degree. to 250.degree. C.

Growing community of inventors

Neckarsteinach, Germany

Erich Fretschner