Pyrazole Studies. VI. Variation of the Basic Properties of Pyrazolones with Substitution in the Pyrazolone Nucleus.

Acid-Base Titrations in Nonaqueous Solvents

“…The base strength of substituted pyrazoles varies with the nature and position of the substituent group. Veibel, Eggersen, and Linholt (158) studied these effects and determined the pKb values in acetic acid. Kieffer (95) determined the pKn of amines substituted by a phenyl group in the a or ß position.…”

Herbicidal activity of alkylpyrazole amides

“…This procedure (Alberti and Zerbi, 1961) was used for the synthesis of all the pyrazole intermediates required for Table I, with the exception of 11 (Scheme II; intermediate for compound 20). A different procedure for the synthesis of the pyrazole intermediates utilized in Table IV was also described by Alberti and Zerbi (1961) with the exception of 5-chloro-3-methylpyrazole (intermediate for 47; Veibel et al, 1954;Michaelis, 1910).…”

“…The dichloro analogue of 6 could not be prepared by direct chlorination of 3-methylpyrazole as described (Huttel et al, 1956). However, chlorination of 5-chloro-3methylpyrazole (Veibel et al, 1954 The Upjohn Company, Kalamazoo, Michigan 49001. Lachwitz , 1910) with chlorine-potassium carbonate in carbon tetrachloride or bromination as for 3 gave the required intermediates for Table III.…”

A Simple Synthesis of 6-Phenylpyrano[2,3-c]pyrazol-4(1H)-ones

“…2 197-198°C). MS: m/z (%) = 317 (M + + 1, 19), 316 (M + , 81), 225 (37), 186 (22), 158 (27), 91 (100), 67 (23), 65 (25). C,66.79;H,3.92;N,12.98.…”