Synthesis of 5-amino-4-cyanopyrazole from 1,1-dicyanoalkenes and elemental dinitrogen using a tungsten complex

Abstract

Electrochemical reduction of the dinitrogen-derived dicyanovinly hydrazido(2–) complex [WF(dppe)₂N[graphic omitted]HCCN₂]⁺[BF₄]-[dppe = bis(diphenylphosphino)ethane] in tetrahydrofuran yields 5-amino-4-cyanopyrazole in up to 50% yield; when carried out under N₂, the metal-containing product of reduction is [WF(dppe)₂N₂H₂]⁺[BF₄]^–, but under CO the dicarbonyl complex W(dppe)₂(CO)₂ is formed.