1326
S. R. Gondi and D. Y. Son
(m, 2H), 1.90–1.03 (m, 28H), 1.01–0.85 (m, 6H), 0.56 (s, 3H). 13C NMR
(CDCl3): 170.8, 161.8, 141.0, 135.9, 128.4, 128.3, 77.9, 76.1, 66.0, 56.3,
55.9, 50.7, 42.6, 41.8, 40.3, 40.0, 38.7, 35.6, 35.2, 34.8, 34.4, 31.8, 31.6,
28.1, 26.9, 26.3, 26.2, 24.9, 24.0, 23.2, 20.7, 18.4, 11.9. IR (neat): 2938,
2867, 1731, 1600, 1453 (strong), 925 cm21 (medium).
Synthesis of 10
Diol 1 (4.0 g, 0.011 mol) was dissolved in THF (80 mL) and cooled in a water/
ice bath. Triethylamine (3.1 mL, 0.022 mol) was added, and the solution was
stirred for 15 min. p-Toluenesulfonyl chloride (4.2 g, 0.022 mol) was added,
and the resulting mixture was stirred at room temperature for 72 h. Volatiles
were removed using a rotary evaporator, and the residue was extracted with
ethyl acetate (2 ꢀ 100 mL). The organic layers were washed with 10%
aqueous sodium bicarbonate solution and brine, then dried over anhydrous
MgSO4 and filtered. Removal of volatiles using a rotary evaporator gave a
residue, which was purified using column chromatography (SiO2, 30 : 70
EtOAc–hex) to give cholane-3-ol-24-(p-toluenesulfonyl) (3a,5b) as a white
solid (3.75 g, 65%). Rf 0.7 (50 : 50 EtOAc–hex). Mp 2078C (lit. reported as
an oil).[46] 1H NMR (CDCl3): 7.77–7.73 (d, 2H, J ¼ 8.0 Hz), 7.35–7.33
(d, 2H, J ¼ 8.0 Hz), 4.01–3.97 (m, 2H), 3.64–3.58 (m, 1H), 2.44 (s, 3H),
1.93–0.95 (m, 28H), 0.90 (s, 3H), 0.85–0.83 (d, 3H, J ¼ 6.2 Hz), 0.59
(s, 3H). 13C NMR (CDCl3): 144.5, 133.2, 129.7, 127.7, 71.7, 71.2, 56.4,
55.9, 42.5, 42.0, 40.3, 40.0, 36.3, 35.7, 35.3, 35.1, 34.4, 31.3, 30.4, 28.1,
27.1, 26.3, 25.4, 24.1, 23.2, 21.5, 20.7, 18.3, 11.9. IR (neat): 2931, 1176
(strong), 1598, 1448, 1176 cm21 (medium). Elemental analysis: calcd.: C,
72.05; H, 9.36. Found: C, 71.60; H, 9.25.
Cholane-3-ol-24-(p-toluenesulfonyl) (3a,5b) (2.0 g, 0.0038 mol) was
dissolved in acetone (60 mL), and sodium iodide (1.15 g, 0.0078 mol) was
added. The resulting mixture was refluxed for 4 h, and then volatiles were
removed using a rotary evaporator. The residue was extracted with ethyl
acetate (2 ꢀ 100 mL); the combined organic layers were washed with 10%
aqueous sodium bicarbonate solution and brine, and then dried over
anhydrous MgSO4 and filtered. Removal of volatiles using a rotary evaporator
gave a residue, which was purified using column chromatography (SiO2,
10 : 90 EtOAc–hex) to give cholane-3-ol-24-iodo (3a,5b) as a white solid
(1.65 g, 92%). Rf 0.8 (50 : 50 EtOAc–hex). Mp 1438C (lit. mp 131–
1348C[46]). 1H NMR (CDCl3): 3.64–3.62 (m, 1H), 3.20–3.12 (m, 2H),
1.94–1.04 (m, 28H), 0.92-0.91 (d, 6H, J ¼ 4.8 Hz), 0.64 (s, 3H). 13C NMR
(CDCl3): 71.8, 56.4, 56.0, 42.6, 42.0, 40.4, 40.1, 36.8, 36.4, 35.8, 35.4,
35.0, 34.5, 30.5, 30.3, 28.2, 27.1, 26.4, 24.1, 23.3, 20.8, 18.6, 12.0, 7.8. IR
(KBr): 3332 (broad peak-OH), 2927, 2863, 1449, 1360, 1176 (strong),
917 cm21 (medium). Elemental analysis: calcd.: C, 61.01; H, 8.75. Found:
C, 60.95; H, 8.75.