Hydrochloric Acid → 3-(Chloromethyl)benzo(b)thiophene

Participants

Reaction Steps

HCl (g) was bubbled vigorously through a mixture of thianaphthene (17.0 g, 126.68 mmol), 37% aq. formaldehyde (15 mL) and conc HCl (15 mL) until the reaction temperature rose to 65° C. At this time, the flow of HCl gas was reduced to a slow stream which was maintained for 1.5 hour. The reaction mixture was diluted with H2O (50 mL) and subsequently extracted with ether (2×50 mL). The combined ethereal extracts were dried over Na2SO4 and concentrated under reduced pressure to yield 1 as a straw colored liquid 21.0 g (90.7%). 1H NMR (CDCl3) δ4.90 (s, 2, CH2 --C1), 7.25 (s, 1, CH--S), 7.45 (m, 2, phenyl), 7.88 (m, 2, phenyl).

Provenance & Evidence