Propargyl bromide → 7-Nitro-3-prop-2-ynyl-2,3,4,5-tetrahydro-1H-benzo[d]azepine

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Reaction Steps

7-Nitro-2,3,4,5-tetrahydro-1H-benzo[d]azepine nitric acid salt (1.0 g, 3.94 mmol) was dissolved in acetone (100 mL) followed by addition of Cs2CO3 (3.84 g, 11.82 mmol, 3.0 eq) and propargyl bromide (80% in toluene) (463 μL, 4.33 mmol, 1.1 eq). The reaction was stirred at room temperature for 24 hours. The solution was then concentrated under reduced pressure and the residue was taken up in CH2Cl2 (100 mL) and washed with water (100 mL). The organic layer was dried (sodium sulfate), filtered, and concentrated under reduced pressure. Purification by silica gel chromatography using a gradient of 0-10% MeOH/CH2Cl2 as the eluting solvent to obtain 7-nitro-3-prop-2-ynyl-2,3,4,5-tetrahydro-1H-benzo[d]azepine as a yellow solid (756 mg, 83%). m.p.=122-125° C.; LCMS (m/e) 231 (M+1); 1H-NMR (CDCl3, 400 MHz) δ 8.05-7.98 (m, 2H), 7.30-7.23 (m, 1H), 3.49-3.43 (m, 2H), 3.13-3.02 (m, 4H), 2.84-2.71 (m, 4H), 2.26-2.22 (m, 1H).

Provenance & Evidence