反应详情

A solution of 2,2,12,12-tetramethyl-6,8-dithiatridecane-1,13-dioic acid ethyl ester (7.16 g, 18.25 mmol) and sodium hydroxide (3.13 g, 76 mmol) in ethanol (40 mL) and deionized water (4 mL) was heated to reflux for 2 h. The ethanol was evaporated and the residue dissolved in water (30 mL) and extracted with diethyl ether (20 mL). The aqueous layer was acidified with 2 N hydrochloric acid to pH 2 and extracted with diethyl ether (2×20 mL). The combined organic layers were washed with saturated sodium chloride solution (15 mL), dried over MgSO4, and concentrated to give the crude product (4.79 g) as an oil, which solidified on standing. Recrystallization (hexanes/ethyl acetate=2/1) yielded 2,2,12,12-tetramethyl-6,8-dithiatridecane-1,13-dioic acid (2.9 g, 47%) as nice white needles. Mp.: 72.0-72.5° C.). 1H NMR (300 MHz, CDCl3/TMS): d (ppm): 11.55 (br, 2H), 3.65 (s, 2H), 2.62 (t, J=6.8 Hz, 4H), 1.70-1.51 (m, 8H), 1.21 (s, 12H). 13C NMR (75 MHz, CDCl3/TMS): d (ppm): 184.76, 41.99, 39.54, 35.20, 31.07, 24.87, 24.54. HRMS (HR, LSIMS, gly): Calcd. for C15H29O4S2 (MH+): 337.1507, found 337.1508. Anal. (C15H28O4S2) calcd. (found): C, 53.54 (53.38); H, 8.39 (8.26); S, 19.06 (19.29).

1. temperatureto reflux for 2 h
2. customThe ethanol was evaporated
3. dissolutionthe residue dissolved in water (30 mL)
4. extractionextracted with diethyl ether (20 mL)
5. extractionextracted with diethyl ether (2×20 mL)
6. washThe combined organic layers were washed with saturated sodium chloride solution (15 mL)
7. dry with materialdried over MgSO4
8. concentrationconcentrated
9. customto give the crude product (4.79 g) as an oil, which
10. customRecrystallization (hexanes/ethyl acetate=2/1)