Abstract: | Useful oxidation reaction of 2‐alkyl(aryl)‐3‐methylthiopyrano[4,3‐c]pyrazol‐4(2H)‐ones, leading to either the corresponding sulfoxides or sulfones, using hydrogen peroxide and acetic acid in 1,2‐dichloroethane, is described. Bioassay results showed that the products have some herbicidal activity. © 2005 Wiley Periodicals, Inc. 16:255–258, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20067 |