5-Chloro-4-nitro-1H-pyrazoles reacted with arylsulfonyl-, cyano-, and acetylacetic acid esters in DMSO in the presence of potassium carbonate to give 5-[alkoxycarbonyl(acetyl, cyano, or arylsulfonyl)-methyl]-substituted 4-nitropyrazoles which may be promising from the viewpoint of preparation of other functionalized pyrazole derivatives and bicyclic ensembles.