1181267-36-6

N-Boc 1-(2-Ethyoxyethyl)-2-(4-piperidinyl)-1H-benzimidazole is an impurity of Bilastine (B385000), which is a novel, nonsedating H1-antihistamine developed for symptomatic treatment of allergic rhinitis and chronic idiopathic urticaria.

To a reaction flask was added 38.00 g of 1-chloro-2-ethoxyethane (Compound 4, 0.35 mol) and 90.4 g of tert-butyl 4-(1H-benzo[d]imidazol-2-yl)piperidine-1-carboxylate (Compound 3, 0.3 mol). Under cooling in an ice bath, 7 mL of polyethylene glycol-400 (containing 0.25 mol NaOH and 0.1 mol Na2CO3) was slowly added, and the reaction mixture was stirred vigorously at 40 °C for 2 hours. After completion of the reaction, the reaction solution was cooled to room temperature, extracted with ether, and the organic phase was washed with saturated brine, dried over anhydrous sodium sulfate and filtered. The solvent was removed by distillation under reduced pressure to give 103.1 g tert-butyl 4-(1-(2-ethoxyethyl)-1H-benzo[d]imidazol-2-yl)piperidine-1-carboxylate (compound 5) in 92% yield.

[1] Synthetic Communications, 2011, vol. 41, # 9, p. 1394 - 1402
[2] Patent: CN106146459, 2016, A. Location in patent: Paragraph 0055; 0056; 0057; 0058; 0059; 0060
[3] Patent: WO2014/188453, 2014, A2. Location in patent: Page/Page column 29