Sodium Hydroxide → 6-Chloro-1-piperidin-4-yl-1,3-dihydro-benzoimidazol-2-one

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Reaction Conditions

Reaction Steps

D7 (12.0 g, 37 mmol) was suspended in a 2.5 M aqueous solution of sodium hydroxide (150 mL). The suspension was refluxed for 15 hours and then allowed to cool. The solution was acidified with 6 M HCl (˜70 mL) until no more effervescence was observed (˜pH 2) and then the pH was carefully adjusted to pH 8.5 using 2.5M aqueous NaOH whilst the solution was cooled to 0° C. The resulting precipitate was collected by filtration, washed with cold water (20 mL) and then dried under vacuum at 40° C. for 15 hours to give the title compound (7.1 g, 76% yield) as a light brown solid (Rf: Baseline (ethyl acetate)). 1H-NMR (300 MHz, DMSO-d6) □ 11.11 (1H, br s), 8.97 (1H, br s), 7.52 (1H, s), 6.99-6.97 (2H, m), 4.51-4.48 (1H, m), 3.33-3.31 (2H, m), 3.02-2.97 (2H, m), 2.48-2.46 (2H, m), 1.81-1.77 (2H, m); m.p.>300° C.

Provenance & Evidence