Ethylene Glycol → 6-bromo-2,3-dihydrospiro[4H-1-benzothiopyran-4,2'-[1,3]dioxolane]

Participants

Reaction Steps

14.7 g (0.060 mol) of the title compound of Step B, 11 mL (0.19 mol) of ethylene glycol (purchased from Aldrich Chemical Company), and 0.4 g (2.10 mmol) of p-toluenesulfonic acid monohydrate (purchased from Aldrich Chemical Company) were added to 125 mL of toluene. The solution was stirred at reflux under nitrogen overnight, and was then washed with 1M sodium carbonate (2×250 mL), followed by water (2×250 mL). The organic layer was dried (Na2SO4), filtered, and evaporated to dryness to yield 13.58 g of the title compound of Step C as an oil. 1H NMR (CDCl3): δ2.2 (m,2H), 3.16 (m,2H), 4.1 (m,2H), 4.2 (m,2H), 7.0-7.6 (3H).

Provenance & Evidence