Preparation of N-substituted pyrazoles

US5468871A · kind A · utility

Assignee

• BASF SE

Inventors

• Klaus Ebel · Lampertheim, DE
• Juergen Schroeder · Ludwigshafen, DE
• Carsten Groening · Mannheim, DE
• Toni Dockner
• Hans Rupert Merkle · Ludwigshafen, DE

Key dates

• Filing date: Nov 7, 1994
• Grant date: Nov 21, 1995
• Expiry date: Nov 7, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D249/08
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

N-substituted-pyrazoles of the formula ##STR1## wherein R.sup.1 is C.sub.1 -C.sub.12 -alkyl or C.sub.7 -C.sub.20 -alkyl, and R.sup.2, R.sup.3 and R.sup.4 independently denote hydrogen, C.sub.1 -C.sub.12 -alkyl, phenyl, C.sub.7 -C.sub.20 -alkylphenyl and C.sub.7 -C.sub.20 -phenylalkyl, are prepared by reacting a pyrazole of the formula ##STR2## wherein R.sup.2, R.sup.3 and R.sup.4 have the meanings above, with an alcohol or ether of the formula EQU R.sup.1 --O--R.sup.5 III, wherein R.sup.5 is hydrogen or R.sup.1, at a temperature of from 200.degree. to 550.degree. C. and a pressure of from 0.001 to 50 bar in the presence of a heterogeneous catalyst, preferably one which contains acid centers such as the oxides of aluminum, silicon, titanium and/or zirconium, optionally doped with phosphoric acid.