A solution of 1′-(4-ethyl-3-methoxybenzoyl)spiro[benzo[b]pyrrolo[1,2-d][1,4]oxazine-4,4′-piperidine]-7-carboxylic acid (40 mg, 0.090 mmol), HATU (34 mg, 0.090 mmol), N-methylamine hydrochloride (6.0 mg, 0.090 mmol) and iPr2NEt (62 μL, 0.36 mmol) in DMF (1 mL) was stirred at room temperature overnight. The reaction mixture was filtered and purified by reverse phase LC-MS (10-99% CH3CN/H2O). Pure fractions were combined and evaporated to yield 1′-(4-ethyl-3-methoxybenzoyl)-N-methylspiro[benzo[b]pyrrolo[1,2-d][1,4]oxazine-4,4′-piperidine]-7-carboxamide. ESI-MS m/z calc. 459.5, found 460.5 (M+1)+; Retention time: 1.73 minutes (3 min run).
