Process for preparing 3,5-bis(haloalkyl)pyrazole derivatives from a,a-dihaloamines

A process for preparing a 3,5-bis(haloalkyl)pyrazole of formula (Ia) and (Ib)

• in which
• R1 and R3 are each independently selected from C1-C6-haloalkyl;
• R2 is selected from H, Hal, COOH, (C═O)OR4, CN and (C═O)NR4R5;
• R4 and R5 are each independently selected from C1-12-alkyl, C3-8-cycloalkyl, C6-18-aryl, C7-19-arylalkyl and C7-19-alkylaryl, or
• R4 and R5 together with the nitrogen atom to which they are bonded may form a four-, five- or six-membered ring;
• comprising in (A), reacting one or more α,α-dihaloamines of the formula (II),
• in which
• X is independently selected from F, Cl or Br;
• R5 and R6 are each independently selected from C1-12-alkyl, C3-8-cycloalkyl, C6-18-aryl,
• C7-19-arylalkyl and C7-19-alkylaryl or where
• R5 and R6 together with the nitrogen atom to which they are bonded may form a five- or six-membered ring;
• R1 is as defined above;
• with one or more compounds of formula (III),
• in which
• R2 and R3 are as defined above;
• to form the compound of formula (IV) or (V)
• and in (B) in the presence of an acid and hydrazine cyclization of (IV) or (V) takes place to form (la/Ib).