Concise One-Pot Multicomponent Reaction Approach to Mono­fluo­rinated Spiro-pyrazole-pyridine Derivatives without Additional Catalyst

Abstract Monofluorinated bis-heterocyclic spirocycles: functionalized ethyl 9-fluoro-8-methyl-1,4-dioxo-2,3,6,10-tetraphenyl-2,3,7-triazaspiro[4.5]dec-7-ene-9-carboxylate derivatives were efficiently synthesized from readily available 1,2-diphenylpyrazolidine-3,5-dione, ethyl 2-fluoroacetoacetate, aromatic aldehydes, and ammonium acetate via one-pot four-component reactions in the absence of additional catalyst. In the protocols, ammonium acetate serves not only as the fourth component but also as the catalyst.