Functionalized bis(1-methylimidazol-2-yl)methane and 1-(1-methylimidazol-2-yl)methyl-3,5-dimethylpyrazole and their reactions

• The modification of bis(1-methylimidazol-2-yl)methane at the methylene group.
• Reactivity of functionalized bis(1-methylimidazol-2-yl)methane has been investigated.
• The lithiation of 1-(1-methylimidazol-2-yl)methyl-3,5-dimethylpyrazole.
• The functionalized pyrazole-based ligand shows different reaction pattern.

Bis(1-methylimidazol-2-yl)methane and 1-(1-methylimidazol-2-yl)methyl-3,5-dimethylpyrazole [CH2(min)(pz)] could be deprotonated with n-BuLi at the bridging carbon atom. The corresponding anions were inactive in the reaction with Ph3SnCl but reacted with sulfur, followed by reaction with Ph2SnCl2 to give organotin derivatives Ph2ClSnSCH(min)2 (1) and Ph2ClSnSCH(min)(pz) (4) (min = 1-methylimidazol-2-yl and pz = 3,5-dimethylpyrazol-1-yl, respectively). The structure of 1 determined by X-ray structural analyses indicated that bis(1-methylimidazol-2-yl)methylthiolate acted as a bidentate monoanionic κ2-[N,S] chelating ligand. Reaction of 1 with W(CO)5THF yielded heterobimetallic complex Ph2ClSnSCH(min)2W(CO)5 (2), while similar reaction of 4 with W(CO)5THF resulted in the decomposition of 4 to give pyrazole derivative W(CO)5(pzH). The structure of 2 has been confirmed by X-ray structural analyses, showing that 1 coordinated to the tungsten atom through the free nitrogen atom. Reaction of CH2(min)(pz) with W(CO)5THF yielded bidentate chelating complex CH2(min)(pz)W(CO)4, which when treated with n-BuLi, followed by reaction with Ph3SnCl, gave the final product CH2(minSnPh3)(pz)W(CO)4.

The modification of bis(1-methylimidazol-2-yl)methane and 1-(1-methylimidazol-2-yl)methyl-3,5-dimethylpyrazole at the methylene group has been successfully carried out. These functionalized ligands showed markedly different reaction patterns, compared to the analogs of bis(pyrazol-1-yl)methanes.Figure optionsDownload as PowerPoint slide