Diethylaminoethyl chloride → Etonitazene 6-nitro isomer

Participants

Reaction Conditions

Reaction Steps

To a small, argon purged flask fitted with a condenser and magnetic stirbar is charged Sodium Hydride (60 wt %, 74 mg, 1.850 mmol) and anhydrous dioxane (5 mL) and stirring begun. A solution of 2-(4-Ethoxy-benzyl)-5-nitro-1H-benzimidazole 42 (550 mg, 1.850 mmol) in anhydrous dioxane (10 mL) was added dropwise to the suspension of sodium hydride and the mixture heated to 65° C. for 90 minutes at which time a solution of (2-Chloroethyl)-diethyl-amine (251 mg, 1.850 mmol) in anhydrous dioxane (5 mL) is added dropwise to the hot solution. After 60 minutes at 65° C. the mixture is cooled to room temperature, filtered and solvent removed under reduced pressure to afford crude. The product was purified using dry silica gel column chromatography eluting with 25 mL portions of solvent system (1.25% 2M NH3 in methanol/98.75% dichloromethane to 2.5% 2M NH3 in methanol/97.5% dichloromethane). The enriched fractions were further purified using silica gel column chromatography eluting with 50% ethyl acetate/50% hexanes to 70% ethyl acetate/30% hexanes to afford a pale yellow-colorless solid 43 {2-[2-(4-Ethoxy-benzyl)-6-nitro-benzoimidazol-1-yl]-ethyl}-diethyl-amine Yield: 100 mg (13.6%). 1H NMR (DMSO) δ: 0.70 (t, 6H, J=7.1), 1.30 (t, 3H, J=6.9), 2.39 (q, 4H, J=7.1), 2.50 (m, 2H), 3.98 (q, 2H, J=6.9), 4.28-4.36 (s, 2H; m, 2H) 6.87 (d, 2H, J=8.7), 7.20 (d, 2H, J=8.6), 7.72 (d, 1H, J=9.0), 8.06 (dd, 2H, J=8.9, 2.1), 8.51 (d, 1H, J=2.1); MS (ESI): 397 (MH+, 100%).

Provenance & Evidence