abstract |
A process for preparing a pyrazole compound of formula V, or a salt, stereoisomer, tautomer or N-oxide thereof ** (See formula) ** comprising the step of cyclizing an α, β-unsaturated carbonyl compound substituted by hydrazone of formula IV ** (See formula) ** 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 Bronsted acids, ammonium salts of Bronsted 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. |