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US 2019/0055200 A1Published application
Catalytic Hydrogenation Process for Preparing Pyrazoles
AssigneeBASF SE
InventorsEric George KLAUBER, Michael RACK, Sebastian SOERGEL, Birgit GOCKEL, Roland GOETZ
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Abstract
The present invention relates to a catalytic process for preparing pyrazoles comprising the step of cyclizing hydrazone substituted α,β-unsaturated carbonyl compounds by reacting them with hydrogen in a reaction mixture comprising as components (a) a hydrogenation catalyst, (b) an acid selected from Brønsted acids, ammonium salts of Brønsted acids, and Lewis acids, (c) a protic solvent, and optionally (d) an aprotic solvent.
Claims24
1-22. (canceled)
A process for preparing a pyrazole compound of formula V, or a salt, stereoisomer, tautomer or N-oxide thereof
- comprising the step of cyclizing a hydrazone substituted α,β-unsaturated carbonyl compound of formula IV
- by reacting it with hydrogen,
- wherein the compound of formula IV is provided in a reaction mixture comprising as components:
- (a) a hydrogenation catalyst;
- (b) an acid selected from Brønsted acids, ammonium salts of Brønsted acids, and Lewis acids;
- (c) a protic solvent;
- and optionally
- (d) an aprotic solvent;
- and wherein
- R1 is C(O)ORc, wherein Rc is C1-C4-alkyl or benzyl;
- R2 is CH3, or fluoromethyl;
- R3 is H;
- R4 is selected from C1-C4-alkyl, which group is unsubstituted, or partially halogenated, and
- R5 is selected from C1-C4-alkyl.
11 more elements
A composition comprising
- (1) a compound of formula IV
- wherein
- R1 is C(O)OCH2CH3;
- R2 is CH3;
- R3 is H;
- R4 is CH(CH3)2;
- and R5 is CH3;
- and
- (2) at least one component selected from
- (a) a hydrogenation catalyst comprising palladium or platinum,
- (b) an acid selected from Brønsted acids, ammonium salts of Brønsted acids, and Lewis acids, and
- (c) methanol or ethanol.
9 more elements
Dependencies are inferred from the claim text.