Hydrochloric Acid → p-Toluenesulfinic acid

To a suspension of p-toluenesulfinic acid sodium salt (30 g) in H2O (100 mL) was added methyl t-butyl ether (50 mL) followed by dropwise addition of conc HCl (15 mL). After stirring 5 min, the organic phase was removed and the aqueous phase was extracted with methyl t-butyl ether. The organic phase was dried (Na2SO4) and concentrated to near dryness. Hexane was added and the resulting precipitate collected to afford p-toluenesulfinic acid; yield 22 g. p-Toluenesulfinic acid (22 g, 140.6 mmol), p-fluorobenzaldehyde (22 mL, 206 mmol), formamide (20 mL, 503 mmol) and camphor sulphonic acid (4 g, 17.3 mmol) were combined and stirred at 60° C. 18 h. The resulting solid was broken up and stirred with a mixture of MeOH (35 mL) and hexane (82 mL) then filtered. The solid was resuspended in MeOH/hexanes (1:3, 200 mL) and stirred vigorously to break up the remaining chunks. Filtration afforded the title compound (27 g, 62% yield): 1H NMR (400 MHz, CDCl3) δ8.13 (s, 1H), 7.71 (d, 2H), 7.43 (dd, 2H), 7.32 (d, 2H), 7.08 (t, 2H), 6.34 (d, 1H), 2.45 (s, 3H).

1. customthe organic phase was removed
2. extractionthe aqueous phase was extracted with methyl t-butyl ether
3. dry with materialThe organic phase was dried (Na2SO4)
4. concentrationconcentrated
5. additionHexane was added
6. customthe resulting precipitate collected

ORD record

ord-6b1f60c13f5d486592ed0f80529e842f

Source dataset

uspto-grants-2001_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06218537B1