Benzenesulfonyl chloride → 3-(4-methoxybenzyl)-7-(phenylsulfonyl)-6,7,8,9-tetrahydro-3H-pyrazolo[3,4-c][2,7]naphthyridine

Participants

Reaction Steps

To a solution of 3-(4-methoxy-benzyl)-6,7,8,9-tetrahydro-3H-pyrazolo[3,4-c][2,7]naphthyridine (0.129 g, 0.43 mmol) in dichloromethane (8 mL) and Et3N (0.13 mL, 0.86 mmol) was added benzenesulfonyl chloride (62 μL, 0.47 mmol). The reaction mixture was shaken at room temperature for 1 hour. The solvent was then removed under reduced pressure and the residue obtained was partitioned between EtOAc and aqueous NaOH. The organic layer was then separated, washed with brine (2×10 mL), concentrated under reduced pressure. The crude product was purified using either flash column chromatography (SiO2, 33% EtOAc in hexane) to give 3-(4-methoxybenzyl)-7-(phenylsulfonyl)-6,7,8,9-tetrahydro-3H-pyrazolo[3,4-c][2,7]naphthyridine as a white solid (0.147 g, 77%) or used in the next step without any further purification. M.p.=136-138° C.; 400 MHz 1H NMR (DMSO-d6) δ: 8.39 (s, 1H), 8.12 (s, 1H), 7.88-7.83 (m, 2H), 7.72-7.59 (m, 3H), 7.18-7.13 (m, 2H), 6.86-6.8 (m, 2H), 5.55 (s, 2H), 4.36 (s, 2H), 3.68 (s, 3H), 3.43, t, J=6.4 Hz, 2H), 3.13 (t, J=6.4 Hz, 2H), 2.54-2.48 (m, 2H); LCMS [M+H]: 435.

Provenance & Evidence