• Reaction with triethyl orthoformate, catalyzed by sulfuric acid, to give the N-ethyl-N-formyl derivative (method as Org. Synth. Coll., 4, 420 (1963)), is the first step in a short and efficient strategy for the synthesis of the quinoline antibiotic norfloxacin: J. Chem. Soc., Chem. Commun., 1319 (1995).