4-Toluenesulfonyl chloride → 2,2,4,6,7-Pentamethyl-5-(p-toluenesulfonylamino)-2,3-dihydrobenzofuran

Temperature

50 °C

5-Amino-2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran (2.00 g, 9.74 mmol) and p-toluenesulfonyl chloride (2.04 g, 10.7 mmol) were dissolved in pyridine (30 ml) and stirred at 50° C. for 1 hour. The reaction mixture was concentrated under reduced pressure and the residue was dissolved in chloroform. The mixture was washed with 1N hydrochloric acid and saturated saline and dried and then the solvent was distilled off under reduced pressure. The residue was purified by column chromatography on silica gel (hexaneethyl acetate, 97:3). The crude crystals were recrystallized from dichloromethane-isopropyl ether to obtain the desired compound (2.41 g, yield: 68.8% yield), m.p. 219°-220° C. (dichloromethane-isopropyl ether).

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. dissolutionthe residue was dissolved in chloroform
3. washThe mixture was washed with 1N hydrochloric acid and saturated saline
4. customdried
5. distillationthe solvent was distilled off under reduced pressure
6. customThe residue was purified by column chromatography on silica gel (hexaneethyl acetate, 97:3)
7. customThe crude crystals were recrystallized from dichloromethane-isopropyl ether

ORD record

ord-3880387ac2fe4b69b09798f43e707123

Source dataset

uspto-grants-1995_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05478844