J. Ternois et al. / Tetrahedron: Asymmetry 18 (2007) 2959–2964
2963
except for modafinic acid for which the ionic liquid
solution was directly dissolved in dichloromethane without
prior extraction.
propanol (90:10) mixture (0.5 mL/min, k = 254 nm, reten-
tion times 22.9 min for (R)-methylphenylsulfoxide and
25.7 min for (S)-methylphenylsulfoxide).
4.7. (Benzhydrylsulfinyl)-acetic acid (modafinic acid)
Modafinic acid was purified by extraction with an aqueous
K2CO3 solution (0.5 M) of the crude product dissolved in
dichloromethane (20 mL), the separation of the aqueous
layer and acidification to pH 1 to precipitate the modafinic
acid, which was collected by filtration and oven dried at
50 °C to give a white solid. 1H NMR (DMSO-d6): d
13.22 (br s, 1H, CO2H) 7.3–7.53 (m, 10H, Ar-H) 5.41 (s,
1H, CH) 3.49 (d, 1H, J = 14.3 Hz, CH2) 3.37 (d, 1H,
J = 14.3 Hz, CH2). 13C NMR (DMSO-d6): d 167.4, 136.6,
134.9, 129.6, 129.1, 128.6, 128.5, 128.1, 128, 69.3, 55.4.
Enantiomeric excess was determined by chiral HPLC on
a Chiralpak AD-H (250 ꢁ 4.6 mm) column eluting with a
Acknowledgements
The authors wish to thank Cephalon for financial support
and a research grant given to J.T. and for the generous gift
of the various modafinil-related thioethers and sulfoxides
used in this study.
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20
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´
´
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20
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