Water → 2-Bromo-5-(1,3-dioxan-2-yl)pyridine

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Reaction Steps

To a solution of 6-bromopyridine-3-carbaldehyde 7 (47.2 g, 254 mmol) in toluene (130 mL) in a 250 mL round-bottom flask was added 1,3-propanediol (38.6 g, 508 mmol) and 10-camphorsulfonic acid (2.95 g, 12.69 mmol). The reaction mixture was heated to reflux, with azeotropic removal of the evolved water, for 1 h, cooled down to r.t. and concentrated. The residue was partitioned between EtOAc (150 mL) and NaHCO3 soln (100 mL). Organic phase was collected and the aqueous phase was extracted with EA (2×150 mL). Combined organic fractions were washed with brine (100 mL), dried over Na2SO4, filtered and concentrated to yield a brown solid which was triturated with Et2O/Hex (10/150 mL) for 1 h, filtered to give 28 (53.98 g, 221 mmol, 87% yield) as a beige solid. MS (m/z): 243.1 (M+1)

Provenance & Evidence