Yield:321309-38-0 18%

Reaction Conditions:

with chlorosulfonic acid at 0; for 0.5 h;

Steps:

15.2

Step 2 3,4-Dihydro-2H-benzo[b][1,4]dioxepine-7-sulfonyl chloride: A solution of chlorosulfonic acid (24 g, 206.0 mmol) and 3,4-dihydro-2H-benzo[b][1,4]dioxepine (10 g, 66.58 mmol) was kept at 0° C. for 30 min. The reaction mixture was poured into 1000 mL of ice/H₂O and extracted from EtOAc (3×100 mL). The combined organic layers were concentrated under reduced pressure. The residue was purified by silica gel chromatography (1:20 EtOAc/hexanes) to give the desired compound, 3.0 g (18%), as a white solid

References:

US2007/27184,2007,A1 Location in patent:Page/Page column 17; 24