Ethylene Glycol → 2-(5-(1,3-Dioxolan-2-yl)pyridin-2-yl)-7-chlorothieno[3,2-b]pyridine

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Reaction Steps

A suspension of 136 (2.69 g, 9.79 mmol), ethylene glycol (2.184 mL, 39.2 mmol), and (1R)-(−)-10-camphorsulfonic acid (0.227 g, 0.979 mmol) in toluene (150 mL) was heated to reflux with a Dean-Stark trap. After 3 h, the mixture was cooled down and filtered through celite (while still warm). The filtrate was washed with water, NaHCO3 (aq., sat.), NaOH (aq) and brine. The solution was then dried over MgSO4 and concentrated to afford compound 137 (2.77 g, 89% yield) as an off-white solid. MS (m/z): 319.1 (M+H).

Provenance & Evidence