• Reactant for stereoselective preparation of spirobicyclic and bis-spirotricyclic pyrazolidinones1 • Reactant for regioselective preparation of spirocyclic oxindole-butenolides2 • Reactant for synthesis of spiro-oxindoles3 • Reactant for preparation of unsymmetrical oxindoles4 • Reactant for stereoselective preparation of hydroxyloxindoles via Morita-Baylis-Hillman reaction4 • Reactant for preparation of pyridinecarboxylic acid [(oxo)indolylidene)hydrazide derivatives (Schiff base hydrazides) as antibacterial agents5