Acetylene based short route from 2,2,6,6-tetramethylpiperidin-4-one oxime to 2-(pyrazol-5-yl)-4,5,6,7-tetrahydropyrrolo[3,2-c]pyridines

Recent Strides in the Transition Metal-Free Cross-Coupling of Haloacetylenes with Electron-Rich Heterocycles in Solid Media

“…The formation of tetrahydroindolyl dihydrodiazepine 68b.5.4. Cyclization with Hydrazine: Synthesis of Pyrrolyl PyrazolesThe building up of the pyrazole ring over acetylenic moiety of pyrrolopyridine propynones 21 via its ring closure with hydrazine gave 4,5,6,7-tetrahydropyrrolo[3,2-c]pyridine-pyrazole ensembles 69 in 92-98% yields (Scheme 38)[59].…”