The use of sodium hydrogen carbonate under solvent‐free conditions and microwave irradiation is by far the best method for N‐alkylating pyrazoles. The yields are good and the method is devoid of side reactions (quaternization, isomerization, hydrogen halide elimination). Solvent‐free conditions are the only ones that allow us to prepare 1‐substituted pyrazoles from secondary halides. The procedure using quaternary salts in one‐pot provides an interesting alternative for the preparation of 1‐heteroarylpyrazoles.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.