Hydrochloric Acid → N-{2-[4-(2,3-Dihydro-1,4-benzodioxin-5-yl)piperazin-1-yl]propyl}pyridin-2-amine

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Reaction Steps

Compound VII as a crude oil (49.0 g, 0.106 mol) is dissolved in ethanol (150 mL) and to this solution is added 1N HCl solution in ethanol (212 mL). The resulting solution is refluxed for 18 h, then concentrated in vacuum to a small volume (˜100 mL) until product starts to crystallize. Ether (100 mL) is added slowly to resulting slurry, in portions, and the mixture is stirred at ambient temperature for 2 h. Slightly gray crystals are filtered and washed with ethanol/ether (50:50) mixture to afford 22.2 g of compound VIII (49% over 3 steps). The purity is determined to be 97.9% by LC-MS. This batch is then recrystallized from methanol (150 mL) and ether (200 mL) to produce 19.3 g of VIII with 99% purity. 1H NMR (CD3OD) δ 8.01 (m, 2H), 7.30 (d, J=9 Hz, 1H), 7.08 (t, J=7.4 Hz, 1H), 6.82 (t, J=8.1 Hz, 1H), 6.63 (m, 2H), 4.30 (m, 4H), 4.10 (m, 1H), 3.80–2.90 (m, 9H), 1.55 (d, J=6.2 Hz, 3H). MP=245–248° C.

Provenance & Evidence