Basf Aktiengesellschaft

Juan Jose Aiscar Bayeto

Michael Rack

Jochem Henkelmann

Volker Maywald

Norbert G&ouml;tz

Roland G&ouml;tz

Heike Becker

Adrian Steinmetz

Method for producing 1-substituted 5-Hydroxypyrazoles

The invention relates to a method for the production of 1-substituted 5-hydroxypyrazoles of formula (I) wherein R,is C,-C,-alkyl, C,-C,-alkenyl, C,-C,-alkinyl, C,-C,-cycloalkyl or C,-C,-alkoxy, whereby these groups can be substituted by halogen, C,-C,-alkoxy, phenoxy, C,-C,-alkoxycarbonyl, C,-C,-alkylthiocarbonyl or a cyclic ring system with 3-14 ring atoms, by reacting a) an alkylvinylether of general formula (III) wherein R,is C,-C,-alkyl or C,-C,-cycloalkyl, with phosgene (IVa), &ldquo;diphosgene&rdquo; (IVb) or &ldquo;triphosgene&rdquo; (IVc) to form acid chlorides of formula (V), b) transforming said acid chlorides by eliminating hydrogen chloride into the corresponding 3-alkoxyacrylic acid chloride of formula (VI) and c) reacting said acid chloride with hydrazines of formula (VII) wherein R,has the above cited meaning, to form 5-hydroxypyrazoles of formula (I).

Method for the production of 1-substituted 5-hydroxypyrazoles

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Mannheim, Germany

Juan Jose Aiscar Bayeto