Dimethylformamide → 1'-Benzylspiro[benzo[b]pyrrolo[1,2-d][1,4]oxazine-4,4'-piperidine]-1-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

N,N-Dimethylformamide (723 μL, 9.40 mmol), under nitrogen, was cooled to 0° C. and POCl3 (876 μL, 9.40 mmol) was added dropwise. The reaction was stirred for 20 min at 0° C. and a white solid formed. A solution of 1-benzylspiro[piperidine-4,4′-pyrrolo[2,1-c][1,4]benzoxazine] (2.07 g, 6.27 mmol) in dry DMF (15.5 mL) was added dropwise and the cooling bath was removed. The reaction mixture was stirred for 2 h at 50° C., then cooled down to room temperature and poured onto ice. Sodium hydroxide (1 M) was added until the pH reached 10, then the solution was acidified to pH 6 with 3 M HCl. The mixture was then extracted with EtOAc. The organics were dried over sodium sulfate, filtered and concentrated. The residue was purified by column chromatography (silica gel: 10-70% EtOAc in hexanes) to give 1′-benzylspiro[benzo[b]pyrrolo[1,2-d][1,4]oxazine-4,4′-piperidine]-1-carbaldehyde (1.94 g, 86%). ESI-MS m/z calc. 358.4, found 359.3 (M+1)+; Retention time: 1.16 minutes (3 min run). 1H NMR (400 MHz, CDCl3) δ 9.66 (s, 1H), 8.17-8.07 (m, 1H), 7.38-7.30 (m, 4H), 7.29-7.24 (m, 1H), 7.20-7.13 (m, 2H), 7.09 (m, 2H), 6.20 (d, J=4.1 Hz, 1H), 3.59 (s, 2H), 2.76 (m, 2H), 2.58-2.45 (m, 2H), 2.10-1.96 (m, 4H).

Provenance & Evidence