The Preparation of 1,1′-Carbonyl- and 1,1′-Sulfinyl-dipyrazoles and their Reactions with Carbonyl Compounds

Abstract

The compounds 1,1′-carbonylbis(3-methylpyrazole) (1), 1,1′-carbonylbis(3,5-dimethylpyrazole) (2), and 1,1′-sulfinyldipyrazole (3) have been prepared. They react with aldehydes and ketones in the presence of metal ion catalysts to form 1,1′-alkylidenedipyrazoles together with carbon dioxide, from 1 and 2, or sulfur dioxide, from 3. Tetrapyrazol-1-ylmethane results from the pyrolysis at 200° of 1,1′-carbonyldipyrazole in the presence of cobalt(II) chloride.