Organic & Biomolecular Chemistry
Paper
chemical shifts are referenced to tetramethylsilane as an titled compound as a white powder (2.28 g, 93%), m.p.
internal standard and reported in parts per million (ppm). 110–112 °C. 1H NMR (300 MHz, CDCl3): δ 9.64 (d, 1H), 5.21
N,N-Dimethylacetamide 99+% was purchased from Acros. (s, 1H), 5.02 (s, 1H), 3.95 (dd, 2H), 2.89 (m, 1H), 2.55–2.34
Triterpenoids (1–3) and 2-(1-adamantyl)propene (7) were (m, 2H), 2.23–0.93 (m, 37H). 13C NMR (75 MHz, CDCl3):
obtained using previously developed procedures.17–20 The δ 217.96, 205.93, 151.61, 112.43, 59.34, 54.92, 49.80, 49.53,
other alkenes and reagents were purchased from Aldrich.
47.32, 43.70, 42.61, 40.79, 39.64, 38.66, 36.89, 34.11, 33.66,
32.95, 32.85, 29.06, 28.84, 26.80, 26.62, 21.37, 21.02, 19.60,
15.99, 15.78, 14.20, 10.69. Found: C, 63.60; H, 8.08; I, 22.19.
30-Iodolup-20-en-3β,28-diol (8)
Betulin (1) (4.43 g, 10.00 mmol) was dissolved in N,N-dimethyl- Calc. for C30H45IO2: C, 63.82; H, 8.03; I, 22.48.
acetamide (176 ml) and stirred at 25 °C. Crystalline iodine
(15.23 g, 60.00 mmol) was added to the solution in one
30-Iodo-3β-hydroxylup-20-en-28-oic acid (10)
portion. The reaction mixture was vigorously stirred for 1 min Betulinic acid (3) (4.57 g, 10.00 mmol) was dissolved in N,N-
and poured immediately into a sodium bisulfite (22 g) solution dimethylacetamide (271 ml) and stirred at 25 °C. Crystalline
in water (500 ml). The precipitate was filtered, washed with iodine (15.23 g, 60.00 mmol) was added to the solution in one
cold water (500 ml), then with hot water (60 °C, 500 ml) and portion. The reaction mixture was vigorously stirred for 10 min
dried in a vacuum oven (60 °C, 230 mm Hg), yielding the titled and poured immediately into a sodium bisulfite (22 g) solution
compound as a white powder (5.29 g, 94%), m.p. 163–164 °C. in water (500 ml). The precipitate was filtered, washed with
1H NMR (300 MHz, CDCl3): δ 5.17 (s, 1H), 4.99 (s, 1H), 3.94 cold water (500 ml), then with hot water (60 °C, 500 ml) and
(dd, 2H), 3.81 (d, 1H), 3.33 (d, 1H), 3.19 (dd, 1H), 2.39–2.20 dried in a vacuum oven (60 °C, 230 mm Hg), yielding the titled
(m, 2H), 1.99–0.67 (m, 38H). 13C NMR (75 MHz, CDCl3): compound as a white powder (4.34 g, 75%), m.p. 184–188 °C.
δ 151.96, 112.03, 78.96, 60.34, 55.25, 50.54, 50.33, 47.81, 43.81, 1H NMR (300 MHz, CDCl3): δ 5.19 (s, 1H), 5.00 (s, 1H), 3.95
42.71, 40.94, 38.85, 38.70, 37.21, 37.14, 34.25, 33.76, 33.07, (dd, 2H), 3.19 (dd, 1H), 2.99 (td, 1H), 2.32–0.67 (m, 39H). 13C
29.19, 27.98, 27.37, 26.99, 26.75, 20.92, 18.27, 16.11, 16.02, NMR (75 MHz, CDCl3): δ 179.76, 152.30, 112.21, 78.97, 56.27,
15.36, 14.75, 11.79. 1H NMR (300 MHz, CD3OD): δ 5.18 (s, 1H), 55.30, 51.10, 50.46, 43.35, 42.42, 40.69, 38.85, 38.71, 38.39,
5.00 (s, 1H), 4.01 (dd, 2H), 3.75 (d, 1H), 3.26 (d, 1H), 3.12 (dd, 37.20, 36.85, 34.33, 33.49, 32.01, 29.70, 27.98, 27.38,
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1H), 2.44–2.21 (m, 2H), 2.00–0.67 (m, 38H). 13C NMR (75 MHz, 26.56, 20.93, 18.27, 16.15, 16.08, 15.35, 14.71, 11.14. H NMR
CD3OD): δ 154.07, 112.35, 79.66, 60.20, 56.82, 51.83, 51.76, (300 MHz, CD3OD): δ 5.19 (s, 1H), 5.00 (s, 1H), 4.01 (dd, 2H),
49.03, 45.29, 43.86, 42.21, 40.08, 39.98, 38.65, 38.31, 35.52, 3.15–3.00 (m, 2H), 2.35–0.69 (m, 39H). 13C NMR (75 MHz,
34.86, 34.21, 30.39, 28.64, 28.17, 28.12, 28.06, 22.11, 19.46, CD3OD): δ 180.03, 154.46, 112.36, 79.68, 57.59, 56.90, 52.14,
16.76, 16.61, 16.16, 15.26, 11.61. Found: C, 63.32; H, 8.74; I, 52.03, 44.80, 43.63, 41.99, 40.12, 39.99, 39.74, 38.37, 37.94,
22.02. Calc. for C30H49IO2: C, 63.37; H, 8.69; I, 22.32.
35.67, 34.71, 33.24, 30.92, 28.65, 28.08, 27.97, 22.23, 19.49,
16.79, 16.73, 16.16, 15.18, 11.31. Found: C, 61.64; H, 8.04;
I, 21.52. Calc. for C30H47IO3: C, 61.85; H, 8.13; I, 21.78.
30-Iodolup-20-en-3β,28-diol (8) (electrolysis)
Betulin (1) (1.00 g, 2.26 mmol) and urea (0.68 g, 11.30 mmol)
were dissolved in N,N-dimethylacetamide (60 ml). The solution
was stirred in an electrolyzer at 25 °C. Crystalline iodine
2-Iodo-2-(tert-butyl)propene (11)
A
fresh 1 M iodine solution in N,N-dimethylacetamide
(0.57 g, 2.26 mmol) was added to the solution and direct (12.00 ml, 12.00 mmol) was added to the stirred 2,3,3-tri-
current (0.05 A, 18.96 V) was immediately applied to electrodes methylbut-1-ene (4), (0.59 g, 6.00 mmol). The mixture was vig-
(platinum cathode and anode plates (2.5 cm × 2.5 cm), 0.5 cm orously stirred at 25 °C for 4 min and poured into a sodium
distance between the plates). Electrolysis was stopped after bisulfite (3.5 g) solution in water (100 ml). The resulting emul-
130 min. The reaction solution was poured into a sodium sion was extracted with pentane (2 × 50 ml). The combined
bisulfite solution (1 g) in water (200 ml). The precipitate was organic phase was washed with water (50 ml), dried over
filtered, washed with cold water (100 ml), then with hot water sodium sulfate, filtered and evaporated in a vacuum, yielding
1
(60 °C, 100 ml) and dried in a vacuum oven (60 °C, 230 mm the titled compound as an orange oil (0.34 g, 25%). H NMR
Hg), yielding the titled compound as a white powder (1.22 g, (300 MHz, CDCl3): δ 5.32 (s, 1H), 5.15 (s, 1H), 4.01 (s, 2H), 1.18
94%).
(s, 1H). 13C NMR (75 MHz, CDCl3): δ 154.46, 115.55, 36.24,
29.89, 4.70. Found: C, 37.48; H, 5.80; I, 56.45. Calc. for C7H13I:
C, 37.52; H, 5.85; I, 56.63.
30-Iodo-3-oxolup-20-en-28-al (9)
Betulonic aldehyde (2) (4.41 g, 10.00 mmol) was dissolved in
N,N-dimethylacetamide (55 ml) and stirred at 25 °C. Crystal-
1-Iodomethylcyclohexene (12)
line iodine (15.23 g, 60.00 mmol) was added to the solution in Methylenecyclohexane (0.24 g, 2.50 mmol) was added to the
one portion. The reaction mixture was vigorously stirred for solution of iodine (2.81 g, 14.99 mmol) in N,N-dimethyl-
10 min and poured immediately into a sodium bisulfite (22 g) acetamide (3 ml). The mixture was vigorously stirred at 25 °C
solution in water (500 ml). The precipitate was filtered, washed for 2 min and poured into a sodium bisulfite (6 g) solution in
with cold water (500 ml), then with hot water (60 °C, 500 ml) water (50 ml). The resulting emulsion was stirred and extracted
and dried in a vacuum oven (60 °C, 230 mm Hg), yielding the with pentane (2 × 50 ml). The combined organic phase was
This journal is © The Royal Society of Chemistry 2013
Org. Biomol. Chem., 2013, 11, 2891–2897 | 2895