Brønsted acidic ionic liquids: Green, efficient and reusable catalyst for synthesis of fluorinated spiro [indole-thiazinones/thiazolidinones] as antihistamic agents
and 1-butyl-3-methylimidazolium and inorganic anions such as BF4−, PF6− and PTSA− used as catalysts and reaction medium for synthesis of fluorinated spiro[3H-indole-3,2′-tetrahydro-1,3-thiazine]-2,4′(1H)-diones (4a-f), fluorinated spiro[3H-indole-3,2′-thiazolidine]-2,4′ (1H)-diones (5a-f) in 90–97% yield by one-pot environmentally benign microwave induced technique. Synthesized compounds have been evaluated