DE2441504

1477020 3,5-Diphenylpyrazole AMERICAN CYANAMID CO 15 Aug 1974 [17 Sept 1973] 36038/74 Heading C2C Compounds (I), where R 1 and R 2 are the groups A and B respectively, where Y, Z, Y1, Z1 are hydrogen, halogen, methylthio, methylsulphonyl, cyano, carboxy, C 1-4 carboalkoxy. C 1-4 alkyl, C 1-4 haloalkyl (containing 1-4 halogen atoms) or C 1-4 alkoxy, are made by refluxing a pyrazole (II) in the presence of a catalyst selected from (a) Pd on carbon, (b) Pt on carbon and (c) pre-reduced copper chromite and an inert solvent the latter having a boiling point of at least 200‹ C. when catalyst (c) above is used, and the preparation of a compound (III) where R 3 is C 1-4 alkyl, attached to one or other of the ring nitrogen atoms by alkylating the corresponding pyrazole where R 3 is hydrogen. Pyrazolines (II), where R is hydrogen are made by a ketone R 1 COCH 3 with an aldehyde R 2 CHO, in the presence of a base, in a C 1-4 alcohol at 10-70‹ C., acidifying the mixture to below pH7 and treating the product with hydrazine at below 70‹ C.