2H-1-Benzopyran-6-sulfonyl chloride, 3,4-dihydro-4-oxo- synthesis

Yield:-

Reaction Conditions:

with chlorosulfonic acid in chloroform;

Steps:

70.b EXAMPLE 70

b) To a solution of 4-chromanone (0.59 g, 4.0 mmol) in CHCl₃ (10 mL) was added chlorosulfonic acid (1.0 mL, 15 mmol) and heated to 40° C. for 1 h. After cooling to rt, the solution was poured onto ice and extracted with CH₂Cl₂ (10 mL). The organic layer was washed with 1 M HCl (3*10 mL) and the combined organic extracts were dried over MgSO₄, filtered, and the solvent was removed under reduced pressure to afford 4-oxochroman-6-sulfonyl chloride as a grey solid in quantitative yield. ¹H NMR (CD₃OD) δ8.41 (s, 1H), 8.05 (d, 1H), 7.13 (d, 1H), 4.7 (t, 2H), 3.0 (t, 2H).

References:

US2003/114447,2003,A1