13C NMR (75 MHz, CDCl ): 157.0 ] 146.1 ] 141.5
(22E)-3a,5-cyclo-5a-ergost-22-en-6-one 3 (yield from 30 to
60%): mp: 167È169 ¡C (lit.15 \ 168È169 ¡C). IR lCHCl3/cm~1:
1690, 1455, 1365, 1290, 960.
3
] 138.3 C8 ] C@8 (8a ] 8b), 135.5 C22 ] C@22 (8a ] 8b),
132.0 C23 ] C@23 (8a ] 8b), 129.4 ] 124.0 ] 119.5 ] 115.4
(C7 ] C@7) (8a ] 8b), 75.8 C6 ] C@6 (8a ] 8b), 56.1
C17 ] C@17 (8a ] 8b), 55.9 C14 ] C@14 (8a ] 8b), 43.9
C13 ] C@13 (8a ] 8b), 43.6 C10 ] C@10 (8a ] 8b), 42.8
C24 ] C@24 (8a ] 8b), 41.9 C9 ] C@9 (8a ] 8b), 40.5
C20 ] C@20 (5a ] 5b), 39.8 ] 39.2 C12 ] C@12 (8a ] 8b),
38.3 ] 38.1 C5 ] C@5 (8a ] 8b), 35.4 ] 33.9 C1 ] C@1
(8a ] 8b), 33.0 C25 ] C@25 (8a ] 8b), 28.1 ] 28.0 C16 ] C@16
(8a ] 8b), 25.9 ] 25.7 ] 25.2 ] 25.1 C2 ] C@2 ] C3 ] C@3
(8a ] 8b), 23.6 C15 ] C@15 (8a ] 8b), 22.8 C11 ] C@11
1H NMR (300 MHz, CDCl ): d 5.26È5.11 (2H, m, H-
3
C22 ] H-C23), 2.49È2.37 (1H, m, bH-C7), 2.06È2.02 (1H, m,
aH-C7), 1.02 (3H, d; J \ 6.9 Hz, 21-CH ), 1.01 (3H, s, 19-
3
CH ), 0.91 (3H, d, J \ 6.9 Hz, 28-CH ), [0.84 (3H, d, J \ 6.9
3
3
Hz) ] 0.82 (3H, d, J \ 6.9 Hz)] (26-CH ] 27-CH ), 0.73 (3H,
3
3
s, 18-CH ), 0.72 (1H, dd, J \ 5.1, 5.1 Hz, aH-C4).
3
13C NMR (75 MHz, CDCl ): 209 C6, 135.5 C22, 132.0 C23,
3
57.1 C14, 56.0 C17, 46.8 C10, 46.3 C5, 46.1 C9, 44.8 C7, 42.8
C24, 42.6 C13, 40.1 C20, 39.6 C12, 35.3 C8, 34.8 C3, 33.5 C1,
33.1 C25, 28.4 C16, 25.9 C2, 24.0 C15, 22.8 C11, 20.9 C21,
(19.9 ] 19.6) (C26 ] C27), 19.7 C19, 17.6 C28, 12.2 C12, 11.6
C4.
MS (EI): 396 (M`), 381, 353, 299, 298, 283, 271, 269, 149,
69, 55.
(22E)-3a,5-cyclo-5a,14b-ergost-22-en-6-one (5) (yield from
20 to 35%): mp: 144È147 ¡C. IR lCHCl3/cm~1: 1690, 1450,
1370, 1285, 1150.
(8a ] 8b),
21.1
C21 ] C@21
(8a ] 8b),
17.5
19.9 ] 19.6
C28 ] C@28
C26 ] C@26 ] C27 ] C@27
(8a ] 8b),
(8a ] 8b), 12.7 C18 ] C@18 (8a ] 8b), 9.6 C4 ] C@4 (8a ] 8b).
PuriÐcation of 380 mg of the above crude product by chro-
matography with silica gel (Merck 60 H) using
cyclohexane : ethyl acetate 60 : 1 v/v as the eluent or in
neutral aluminium oxide (Merck 90) using cyclohexane as
eluent a†orded 350 mg of 6,6@-bis-(22E)-3a,5-cyclo-5a-ergosta-
6,8(14),22-triene (7) (100%).
1H NMR (300 MHz, CDCl ): d 5.26È5.11 (2H, m, H-
3
mp: 220 ¡C (dec.). IR lCHCl3/cm~1: 1590, 1455, 1370, 970.
UV (MeOH): 275 nm e \ 6928.
C22 ] H-C23), 2.46 (1H, ddd, J \ 10.8, 7.2, 3.3 Hz, aH-C14),
2.34 (1H, dd, J \ 15.0, 7.5 Hz, aH-C7), 2.20 (1H, dd, J \ 6.9,
5.1 Hz, bH-C7), 1.06 (3H, s, 19-CH ), 0.97 (3H, s, 18-CH ),
1H NMR (300 MHz, CDCl ): d 5.76 (2H, s, H-C7 ] H-C7@),
3
3
3
5.26È5.14 (4H, m, H-C22 ] H-C22@ ] H-C23 ] H-C23@), 1.03
0.93 (3H, d, J \ 6.3 Hz, 21-CH ), 0.91 (3H, d, J \ 6.3 Hz, 28-
3
(6H, d, J \ 6.6 Hz, 21-CH ] 21@-CH ), 0.93 (6H, d, J \ 6.9
CH ), 0.83 (3H, d, J \ 6.9 Hz, 27-CH ), 0.82 (3H, d, J \ 6.6
Hz, 26-CH ), 0.89 (1H, dd, J \ 4.8, 2.7 Hz, H-C4), 0.69 (1H,
3
3
3
3
Hz, 28-CH ] 28@-CH ), 0.89 (6H, s, 19 CH ] 19@-CH ),
3
3
3
3
3
[0.84 (6H, d, J \ 6.9 Hz) ] 0.82 (6H, d, J \ 6.6 Hz)], [26-CH
dd, J \ 4.8, 4.8 Hz, H-C4).
3
] 26@-CH ] 27-CH ] 27@-CH ], 0.79 (6H, s, 18-CH ] 18@-
13C NMR (75 MHz, CDCl ): 210.3 C6, 133.8 C22, 132.6
3
3
3
3
3
CH ), 0.58 (2H, dd, J \ 4.8, 4.8 Hz, aH-C4 ] aH-C4@).
C23, 56.0 C14, 48.3 C9 (46.9 ] 43.3) (C13 ] C10), 43.2 C24,
3
13C NMR (75 MHz, CDCl ): 146.1 (C14 ] C14@), 138.3
(38.2 ] 37.6) (C17 ] C20), 44.9 C7, 46.1 C5, 35.8 C12, 33.4 C1,
33.1 C25, 32.7 C8, 25.9 C2, 34.9 C3, (24.7 ] 24.0) (C15 ] C16),
22.8 C11, 21.9 C21, 19.4 C19, 20.1 C27, 19.7 C26, 17.6 C28,
19.0C18, 11.6 C4.
3
(C6 ] C6@), 135.6 (C22 ] C22@), 132.0 (C23 ] C23@), 124.5
(C8 ] C8@),
122.0
(C7 ] C7@),
56.2
(C17 ] C17@),
44.1 ] 43.6 ] 38.2 (C13 ] C13@) ] (C10 ] C10@) ] (C5 ] C5@),
42.9 (C24 ] C24@), 40.6 (C20 ] C20@), 39.4 (C9 ] C9@), 37.3
(C1 ] C1@), 33.1 (C25 ] C25@), 31.0 (C12 ] C12@), 28.0
(C16 ] C16@), 25.3 ] 24.8 (C15 ] C15@) ] (C11 ] C11@), 25.1
(C3 ] C3@), 21.3 (C21 ] C21@), 20.6 (C2 ] C2@), 20.0 ] 19.7
CIMS (high resolution) m/z: [M ] 1]` 396.338 (calcd.
396.339).
(22E)-3a,5-cyclo-5a-ergosta-6,8(14),22-triene (6) (yield from
10 to 55%): mp: 100-102 ¡C (lit.:15 102È103 ¡C). IR
lCHCl3/cm~1: 1605, 1450, 1370, 1365, 970, 735. UV (EtOH):
261 e \ 24 300 (lit.:16 261 e \ 25 100).
(C26 ] C26@) ] (C27 ] C27@),
19.4
(C19 ] C19@),
17.7
(C28 ] C28@), 17.1 (C18 ] C18@), 11.2 (C4 ] C4@).
HETCOR (1H NMR (300 MHz, CDCl )È13C NMR (75
1H NMR (300 MHz, CDCl ): d 6.14 (1H, d, J \ 9.6 Hz,
3
MHz, CDCl )): 5.76 (H-C7 ] H-C7)È122.0 (C7 ] C7@), 5.22
3
3
H-C7), 5.27È5.15 (3H, m, H-C6 ] H-C22 ] H-C23), 1.04 (3H,
(H-C23 ] H-C23@)È132 (C23 ] C23@), 5.18 (H-C22 ] H-
d, J \ 6.9 Hz, 21-CH ), 0.93 (3H, d, J \ 6.3 Hz, 28-CH ), 0.92
3
3
C22@)È135.6 (C22 ] C22@), 1.03 (H-C21 ] H-C21@)È21.3
(C21 ] C21@), 0.93 (H-C28 ] H-C28@)È17.7 (C28 ] C28@), 0.89
(H-C19 ] H-C19@)È19.4 (C19 ] C19@), [0.84È20.0 ] 0.82È19.7]
[((H-C26 ] H-C26@) ] (H-C27 ] H-C27@))È((C26 ] C26@)
] (C27 ] C27@))], 0.79 (H-C18 ] H-C18@)È17.1 (C18 ] C18@),
0.58 (aH-C4 ] aH-C4@)È11.2 (C4 ] C4@).
MS-IE: 754 ([M]`, 75), 629 (12), 614 (11), 379 (2), 378 (1),
283 (13), 171 (33), 83 (14), 71 (17), 70 (14), 69 (42), 57 (34), 55
(41), 44 (29), 43 (33), 41 (22), 40 (100).
(3H, s, 19-CH ), [0.84 (3H, d, J \ 6.6 Hz) ] 0.83 (3H, d,
3
J \ 6.6 Hz)] [26-CH ] 27-CH ], 0.78 (3H, s, 18-CH ), 0.47
3
3
3
(1H, dd, J \ 7.8, 5.1 Hz, bH-C4).
13C NMR (75 MHz, CDCl ): 146.8 C14, 135.5 C22, 132.0
3
C23, 130.5 C6, 124.7 C8, 124.1 C7, 56.2 C17,
43.9 ] 43.5 ] 37.6 (C13 ] C10 ] C5), 42.9 C24, 40.8 C20, 39.5
C9, 37.4 C1, 33.1 C25, 30.8 C12, 28.0 C16, 26.5 C3, 25.4 ] 25.2
(C11 ] C15), 21.2 C21, 20.4 C2, 20.0 ] 19.7 (C26 ] C27), 19.3
C19, 17.7 C28, 17.0 C18, 15.6 C4.
Found: C: 89.14%, H: 10.86% (calcd.: C: 89.12%, H:
10.88%).
HETCOR (1H NMR (300 MHz, CDCl )È13C NMR (75
3
MHz, CDCl ): 6.14 (H-C7)È124.1 (C7), 5.22 (H-C23)È132.0
3
(C23), 5.20 (H-C6)È130.5 (C6), 5.15 (H-C22)È135.5 (C22), 1.04
Electrolyses of 1 in the presence of benzoic acid and tri-
Ñuoroacetic acid. A solution of 1 (400 mg, 1 mmol) in DMF
(40 mL) with 0.1 M LiClO or NBu BF was electrolyzed in
(H-C21)È21.2 (C21), 0.93 (H-C28)È17.7 (C28), 0.92 (H-C19)
È19.3 (C19), [0.84È20.0 ] 0.83È19.7] [(H-C26 ] H-C27)È
(C26 ] C27)], 0.78 (H-C18)È17.0 (C18), 0.47 (bH-C4)È15.6
(C4).
4
4
4
the
presence
of
either
benzoic
acid
(reduction
potential \ [1.20 V at a glassy carbon electrode) or tri-
Ñuoroacetic acid (reduction potential \ [0.70 V at a glassy
carbon electrode and [0.65 V at a mercury electrode). The
excess factor of the proton donor was initially from 3 to 70
and was kept constant during the electrolysis development.
The amount of electricity consumed was between 6 and 15
faraday per mole. The reaction was then stopped and the solu-
tion neutralized and, after the usual work-up (extraction with
diethyl ether), dried extracts were puriÐed on silica gel (Merck
60 H) using cyclohexane : ethyl acetate 60 : 1 as the eluent to
a†ord the following products.
MS-IE: m/z 378 ([M]`, 25), 363 (7), 335 (12), 281 (18), 253
(11), 252 (37), 212 (33), 55 (100).
Results
Voltammetry
In aprotic medium. The voltammetric analysis of 1 was Ðrst
achieved using a mercury stationary microelectrode in DMF
containing tetrabutylammonium tetraÑuoroborate (0.1 M).
Under such conditions, 1 exhibited, from sweep rates equal
and larger than 0.1 V s~1, a fully reversible step A (*E
Phys. Chem. Chem. Phys., 2001, 3, 2655È2661
2657