General procedure for the synthesis of O-phenylhydroxylamine hydrochloride from compound (CAS: 4846-21-3): a representative method for the preparation of the corresponding O-arylhydroxylamine by hydrazinolysis of N-aryloxyphthalimide (Method 1A): synthesis of compound 1; hydrazine monohydrate (0.401 mL, 8.2 mmol) was slowly added to N-phenoxyphthalimide 9 ( 652 mg, 2.73 mmol) dissolved in a 10% MeOH solution of CHCl3 (25 mL) and the reaction was stirred at room temperature. Upon completion of the reaction (monitored by TLC, 12 h), a white precipitate (phthalazine) appeared in the colorless reaction solution. The reaction mixture was filtered through a silica gel plug and washed with a hexane solution of 30% EtOAc. Removal of EtOAc/hexane gave a light yellow oil, which was distilled by Kugelrohr to give pure phenoxyamine 1 as a clear, colorless oil (238 mg, 80% yield) from K2CO3 (<10 mg); the characterization data are given below. Alternatively, after removal of EtOAc/hexane, the yellow oily substance was dissolved in Et2O and cooled to 0 °C. After being kept at 0 °C for 10 min, a solution of 4N HCl in dioxane was added dropwise until the pH reached 3. The resulting white solid was filtered and washed with Et2O (2 × 10 mL) to give the pure HCl salt (306 mg, 77% yield) of 1. O-Phenylhydroxylamine hydrochloride (1) was prepared as described above as a representative procedure (Method 1A). 1H-NMR (400 MHz , CD3OD) δ 6.84-6.89 (m, 1H), 7.03-7.09 (m, 2H), 7.19-7.25 (m, 2H); 13C-NMR (100 MHz, CD3OD) δ 114.1, 121.6, 130.3, 163.1; LC-MS m/z 110 [MH]+, theoretical value for C6H8NO 110.
