(
)
C. Li et al.rCarbohydrate Research 306 1998 189–195
193
23
.
w x
Ž
over MgSO4, and concentrated. Chromatography of
mg, 14% . 10: mp 126–128 8C; a y70.08 c 1.0,
D
1
Ž
.
Ž
.
the residue on a silica gel column 20:1 petroleum
CHCl3 ; Rf 0.27 4:1 petroleum ether–EtOAc ; H
NMR 300 MHz, CDCl3 : d 7.47–7.39 m, 5 H ,
.
Ž
Ž
.
Ž
.
ether–EtOAc afforded 8 and 9 as a white solid 1.27
g, 97%, 8:9 1:1.5 . The solid was dissolved in
.
Ž
.
Ž
.
5.53 s, 1 H, PhCH , 5.35 d, 1 H, J 4.3 Hz, H-6 ,
Y
Y
Y
Ž
.
Ž
petroleum ether, and after most of 9 was precipitated,
the solution was concentrated and chromatographed
5.07–5.01 m, 3 H, H-3 , H-4 , H-1 , 4.89 t, 1 H,
Y
.
Ž
Y
Y
Y
Y
X
X
J1 ,2 9.2 Hz, J2 ,3 9.2 Hz, H-2 , 4.47 d, 1 H, J1 ,2
X
Ž
.
.
Ž
.
Ž
on a silica gel column 30:1 petroleum ether–EtOAc .
7.3 Hz, H-1 , 4.41 m, 1 H, H-16 , 4.31 dd, 1 H,
X
18
w x
Ž
.
Ž
.
Ž
X
X
X
X
8: mp 138–140 8C; a y84.68 c 1.0, CHCl3 ; Rf
0.40 8:1 petroleum ether–EtOAc ; H NMR 300
MHz, CDCl3 : d 7.50–7.35 m, 5 H , 5.52 s, 1 H,
PhCH , 5.37 d, 1 H, J 4.8 Hz, H-6 , 4.50 d, 1 H,
J1 ,2 7.5 Hz, H-1 , 4.41 m, 1 H, H-16 , 4.32 dd, 1
H, J6 a,5 4.8 Hz, J6 a,6 b 10.3 Hz, H-6 a , 3.77 t, 1 H,
H-6 b , 3.74 t, 1 H, J3 ,X4 8.9 Hz, H-3 , 3.58–3.37
m, 6 H, H-2 , H-4 , H-5 , H-26, H-3 , 1.02 s, 3 H ,
J6 a,5 4.8 Hz, J6 a,6 b 10.5 Hz, H-6 a , 4.05 dd, 1 H,
D
1
Y
Ž
.
.
Ž
Y
Y
Y
Y
J6 a,5 4.4 Hz, J6 a,6 b 12.4 Hz, H-6 a , 3.96–3.90 m,
X
Y
Y
X
.
Ž
.
.
Ž
.
Ž
.
2 H, H-3 , H-6 b , 3.82–3.74 m, 2 H, H-5 , H-6 b ,
3.62–3.54 m, 2 H, H-2 , H-4 , 3.48–3.28 m, 4 H,
H-5 , H-26, H-3 , 2.05, 1.98, 1.97, 1.95 4 s, 12 H ,
X
X
.
Ž
Ž
Ž
.
Ž
X
X
.
Ž
.
Ž
X
X
.
Ž
.
X
.
Ž
X
X
X
X
Ž
.
Ž
.
Ž
Ž
.
1.01 s, 3 H , 0.97 d, 3 H, J 6.9 Hz , 0.89 s, 9 H ,
X
X
.
Ž
.
X
X
Ž
.
Ž
.
.
0.79 d, 3 H, J 3.6 Hz , 0.79 s, 3 H , 0.12 s, 3 H ,
X
X
Ž
.
Ž
.
Ž
.
Ž
.
.
Ž
Ž
.
Ž
.
.
0.09 s, 3 H ; EIMS mrz % : 712 2.0 , 397 72.1 ,
Ž
.
Ž
Ž
.
Ž
Ž
.
Ž
.
Ž
0.97 d, 3 H, J 6.9 Hz , 0.91 s, 9 H , 0.79 d, 3 H, J
331 53.9 , 283 20.5 , 253 38.1 , 169 100.0 , 109
.
Ž
Ž
.
.
.
Ž
.
Ž
.
3.3 Hz , 0.79 s, 3 H , 0.15 s, 3 H , 0.14 s, 3 H ;
30.8 ; Anal. Calcd. for C60H88O17Si: C, 64.96; H,
Ž
.
Ž
.
EIMS mrz % : 778 My1, 0.15 , 722 0.3 , 397
8.00. Found: C, 64.83; H, 8.18.
Ž
.
Ž
Ž
.
Ž
.
Ž
.
.
Ž
.
100 , 379 21.1 , 283 37.5 , 271 22.0 , 253 59.2 ,
Diosgenyl 2,3,4-tri-O-acetyl-a-L-rhamnopyranosyl-
.
Ž
.
Ž
Ž
.
(
)
215 10.5 , 161 25.9 , 149 41.4 , 139 29.1 , 121
1™2 -4,6-O-benzylidene-3-O-tert-butyldimethylsilyl-
Ž
.
Ž
.
Ž
.
Ž
˚
.
Ž
15.2 , 105 14.8 , 69 19.4 ; Anal. Calcd. for
b-D-glucopyranoside 11 .—To a solution of 9 1.33
.
Ž
.
Ž
C46H70O8Si: C, 70.91; H, 9.06. Found: C, 70.62; H,
g, 1.71 mmol and 4 A MS 2.0 g in dry CH2Cl2 30
mL at y78 8C under Ar, was added borontrifluo-
ride–ether complex 0.4 mL, 3.25 mmol , then a
solution of 2 2.1 g, 4.83 mmol in CH2Cl2 10 mL .
The mixture, warmed up naturally to room tempera-
ture and allowed to stir for another 3 h, was then
neutralized with Et3N 0.5 mL , filtered, and concen-
trated. The residue was chromatographed on a silica
20
w x
Ž
.
9.05. 9: mp 123–125 8C;
a
y81.78 c 1.0,
D
1
.
Ž
Ž
.
Ž
.
CHCl3 ; Rf 0.44 8:1 petroleum ether–EtOAc ; H
NMR 300 MHz, CDCl3 : d 7.49–7.33 m, 5 H ,
5.49 s, 1 H, PhCH , 5.38 d, 1 H, H-6 , 4.49 d, 1 H,
J1 ,2 7.8 Hz, H-1 , 4.40 m, 1 H, H-16 , 4.30 dd, 1
.
Ž
Ž
.
Ž
.
Ž
.
Ž
.
.
Ž
X
.
Ž
.
Ž
X
X
X
.
X
X
X
X
Ž
.
H, J6 a,5 4.8 Hz, J6 a,6 b 10.5 Hz, H-6 a , 3.80–3.70
X
X
X
X
Ž
.
Ž
m, 2 H, H-6 b, H-3 , 3.64–3.33 m, 6 H, H-2 , H-4 ,
X
.
Ž
Ž
.
Ž
Ž
.
H-5 , H-26, H-3 , 1.02 s, 3 H , 0.96 d, 3 H, J 6.9
Hz , 0.86 s, 9 H , 0.78 d, 3 H, J 3.8 Hz , 0.78 s, 3
gel column 10:1™8:1 petroleum ether–EtOAc to
.
Ž
.
.
Ž
Ž
.
afford 11 as a white solid 1.8 g, 100% : mp)210
22
D
.
Ž
.
Ž
.
Ž
.
w x
Ž . Ž
H , 0.09 s, 3 H , 0.02 s, 3 H ; EIMS mrz % : 779
8C;
a
y87.68 c 1.0, CHCl3 ; Rf 0.22 8:1
petroleum ether–EtOAc ; 1H NMR 400 MHz,
q
Ž
Ž
.
Ž
.
Ž
.
Ž
.
.
Ž
M , 0.15 , 722 1.1 , 397 100 , 379 16.6 , 283
.
Ž
Ž
.
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
.
37.6 , 271 21.6 , 253 49.5 , 149 19.4 , 139 28.4 ,
CDCl3 : d 7.55–7.44 m, 5 H , 5.49 s, 1 H, PhCH ,
X
.
Ž
.
Ž
.
Ž
Y
Y
105 12.7 , 69 17.1 ; Anal. Calcd. for C46H70O8Si:
5.49 m, 2 H, H-6, H-2 , 5.39 d, 1 H, J1 ,2 0.9 Hz,
H-1 , 5.29 dd, 1 H, J3 ,2 3.3 Hz, J3 ,4 10.1 Hz,
H-3 , 5.15 t, 1 H, H-4 , 4.72–4.68 m, 2 H, J1 ,2
Y
.
.
Ž
Y
Y
Y
Y
C, 70.91; H, 9.06. Found: C, 70.45; H, 8.99.
Y
Y
Ž
.
Ž
Ž
X
X
Diosgenyl 2, 3, 4, 6 - tetra - O - acetyl - b - D -
Y
X
(
)
.
.
Ž
glucopyranosyl- 1™3 -4,6-O-benzylidene-2-O-tert-
8.1 Hz, H-5 , H-1 , 4.50 m, 1 H, H-16 , 4.38 dd, 1
X
Ž
.
.
Ž
X
X
X
X
butyldimethylsilyl-b-D-glucopyranoside 10 .—To a
solution of 8 360 mg, 0.462 mmol and 4 A MS 0.6
g in dry CH2Cl2 15 mL at y78 8C under Ar, was
added borontrifluoride–ether complex 0.07 mL, 0.57
mmol , followed by a solution of 3 520 mg, 1.06
mmol in CH2Cl2 4 mL . The mixture, warmed up
H, J6 a,5 4.0 Hz, J6 a,6 b 10.7 Hz, H-6 a , 4.05 t, 1 H,
X
X
X
˚
Ž
.
Ž
.
Ž
X
X
J3 ,2 8.7 Hz, H-3 , 3.82–3.73 m, 3 H, H-2 , H-6 b,
H-3 , 3.55–3.46 m, 4 H, H-4 , H-5 , H-26 , 2.20,
2.11, 2.05 3 s, 9 H , 1.30 d, J 6.2 Hz, CH3-6 ,
X
X
.
Ž
.
.
Ž
.
Y
Ž
Ž
Ž
.
Ž
.
.
Ž
Ž
Ž
.
Ž
.
Ž
Ž
.
1.12 s, 3 H , 1.06 d, 3 H, J 6.9 Hz , 0.88 s, 3 H ,
.
Ž
.
.
Ž
.
.
0.88 d, 3 H, J 4.2 Hz , 0.82 s, 9 H , 0.02 s, 3 H ,
q
.
Ž
.
Ž
.
naturally to room temperature and allowed to stir for
0.00 s, 3 H ; FABMS mrz % : 1051 M , 3.5 ,
Ž
Ž
.
Ž
.
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.
Ž
.
.
another 7 h, was then neutralized with Et3N 0.1
1049 My1, 3.5 , 637 3.5 , 531 7.5 , 397 100.0 ,
.
Ž
.
Ž
.
Ž
.
Ž
mL , filtered, and concentrated. The residue was
273 70.0 , 171 29.0 , 139 50.0 , 110 73.5 ; Anal.
Calcd. for C58H86O15Si: C, 66.26; H, 8.25. Found:
C, 66.24; H, 8.40.
Ž
chromatographed on a silica gel column 30:1™4:1
.
petroleum ether–EtOAc to afford 10 as a white solid
Ž
.
190 mg, 37% , together with diosgenyl 3-O-acetyl-
Diosgenyl 2,3,4-tri-O-acetyl-a-L-rhamnopyranosyl-
(
)
Ž
.
4,6-O-benzylidene-2-O-tert-butyldimethylsilyl-b-D-
1™2 -4,6-O-benzylidene-b-D-glucopyranoside 12 .
Ž
.
Ž
Ž
.
glucopyranoside 70 mg, 19% , and recovered 8 52
—To a solution of 11 1.79 g, 1.7 mmol in dry THF