1-(2-Chloroethyl)pyrrolidine hydrochloride → 7-nitro-4-(2-(pyrrolidin-1-yl)ethyl)-3,4-dihydro-2H-benzo[b][1,4]thiazine

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Reaction Steps

A mixture of 7-nitro-3,4-dihydro-2H-benzo[b][1,4]thiazine (1 g, 5.10 mmol), 1-(2-chloroethyl)pyrrolidine hydrochloride (1.734 g, 10.19 mmol), and nBu4NBr (0.082 g, 0.255 mmol) in CH2Cl2 (10 mL) and 50% NaOH solution (10 mL) was stirred at room temperature for 16 hours. The mixture was diluted with CH2Cl2 (25 mL) and water (50 mL). The mixture was transferred to a separatory funnel, and the layers were separated. The aqueous layer was extracted in CH2Cl2 (2×25 mL). The combined organic layers were dried (Na2SO4), filtered, and concentrated. The red crude material was subjected to flash chromatography on silica gel (CH2Cl2, then 1.75-5% (2M NH3 in MeOH)/CH2Cl2) to give 7-nitro-4-(2-(pyrrolidin-1-yl)ethyl)-3,4-dihydro-2H-benzo[b][1,4]thiazine as a brown viscous oil (0.63 g, 42%). 1H NMR (DMSO-d6) δ 7.86-7.82 (m, 2H), 6.82 (d, J=9.0 Hz, 1H), 3.81 (t, J=4.8 Hz, 2H), 3.58 (t, J=6.9 Hz, 2H), 3.33 (s, 4H), 3.05 (t, J=5.1 Hz, 2H), 2.63 (t, J=6.9 Hz, 2H), 2.50 (s, 4H), 1.67 (s, 4H); ESI-MS (m/z, %): 296, 294 (MH+, 100), 98 (13).

Provenance & Evidence