N,N-Dimethyl-2-(6-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)ethanamine → N-(4-(2-(dimethylamino)ethyl)-3,4-dihydro-2H-benzo[b][1,4]thiazin-6-yl)thiophene-2-carboximidamide

Participants

Reaction Steps

A suspension of N,N-dimethyl-2-(6-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)ethanamine (75 mg, 0.281 mmol) and palladium, 10 wt. % on activated carbon (29.9 mg, 0.028 mmol) in ethanol (5 mL) was stirred at room temperature under an atmosphere of hydrogen (balloon pressure) for 90 minutes. During this time, the yellow color of the reaction dissipated. To this mixture was then added methyl thiophene-2-carbimidothioate hydroiodide (160 mg, 0.561 mmol), and the resulting suspension was stirred overnight at room temperature. The mixture was then diluted with dichloromethane and filtered to remove palladium. The organic filtrate was further diluted with water and saturated sodium carbonate (1:1). The organic layer was separated, and the aqueous layer was extracted again with dichloromethane. The combined organics were dried, filtered, concentrated, and then chromatographed in 1:19 (2M NH3 in methanol):ethyl acetate, giving the desired product 27 (61 mg, 62.8%). 1H NMR (DMSO-d6) δ 7.71 (d, J=3.3 Hz, 1H), 7.58 (d, J=5.1 Hz, 1H), 7.10-7.06 (m, 1H), 6.83 (d, J=8.1 Hz, 1H), 6.37 (brs, 2H), 6.17 (s, 1H), 6.08 (d, J=7.8 Hz, 1H), 3.63-3.58 (m, 2H), 3.39-3.32 (m, 2H), 3.01-2.96 (m, 2H), 2.42 (t, J=6.9 Hz, 2H), 2.10 (s, 6H); ESI-MS (m/z, %): 347 (MH+, 100), 276 (74); ESI-HRMS calculated for C17H23N4S2 (MH+), calculated: 347.1358, observed: 347.1349; HPLC purity: 95% by area.

Provenance & Evidence