Pyridine → 7-chloro-3,4-dihydro-2H-naphthalen-1-one-O-methyl-oxime

To a stirred solution of 7-chloro-1-tetralone CAS: 26673-32-5 (5.0 g; 27.68 mmol) in methanol (55 ml) was added pyridine (2.87 ml; 34.05 mmol) followed by a portion wise addition of methoxyamine hydrochloride (2.84 g; 34.05 mmol). The reaction mixture was stirred at 24° C. for 16 h under nitrogen. Methanol was removed under reduced pressure, the residue poured in water (300 ml) and 1N hydrochloric acid was added (100 ml). The solution was extracted with dichloromethane (3×150 ml). Combined organic layers were washed with water (300 ml) and dried over sodium sulfate. The solvent was removed in vacuo to afford 6.22 g (100% of theory) of crude 7-chloro-3,4-dihydro-2H-naphthalen-1-one-O-methyl-oxime as a brown oil.