1812
Short Report
n-hexane and the residue obtained on CC over
silica gel using CHCl3±EtOAc step gradient
Table 1. 13C NMR spectral data of
compounds 1 and 2 (75.4 MHz, ppm,
DMSO-d6)
aorded 1 (150 mg) and 2 (260 mg).
C
1
2
Echiodinin (1)
Green±yellow needles (MeOH); mp 264±2658;
2
3
4
5
6
7
8
161.4
109.1
182.0
161.0
97.8
158.5
112.0
177.1
158.0
103.3
163.5
96.4
MeOH
UV
+NaOMe: 265, 390; +NaOAc: 265, 335; +AlCl3:
l
max
nm (log E): 265 (4.40), 335 (4.19);
250, 274, 285 sh, 315 sh, 355; +AlCl3/HCl: 235,
KBr
max
cm 1: 3400 (OH), 2980, 1654
165.1
92.4
265, 315, 355; IR n
(C.O), 1615, 1520, 1456, 1360, 1H NMR (DMSO-
d6): d 12.87 (OH-5), 10.86 (OH-2'), 7.90 (1H, dd,
J = 2,8 Hz, H-6'), 7.40 (1H, dt, J = 2,8 Hz, H-4'),
7.11 (1H, s, H-3), 6.99-7.06 (2H, m, H-3', 5'), 6.73)
(1H, d, J = 2.5 Hz, H-8). 6.35 (1H, d, J = 2.5 Hz,
H-6), 3.90 (3H, s, OMe-7), 13C NMR: Table 1;
ELMS m/z (rel. int): 284 [M]+ (100), 267 [M±OH]+
(1) 255 [M±CHO]+ (5), 254 [M±CO]+ (2), 166
[A1]+ (4), 118 [B1]+ (1).
9
10
1'
2'
3'
4'
5'
6'
1
157.3
104.6
117.0
156.7
116.9
132.8
119.3
128.4
158.7
109.1
117.0
156.6
116.9
132.4
119.2
128.2
104.1
73.5
2
3
4
77.5
69.8
5
75.6
60.8
55.9
6
7-OMe
Echioidinin 5-O-b-D-glucopyranoside (2)
55.9
Pale yellow needles (MeOH), mp 245±2468; FAB-
MS (positive mode) m/z (rel. int): 447 [M + H]+
(5), 285 [M + H-glucosyl]+ (23); UV l
nm
MeOH
max
coside (2) indicated that the glucose moiety in 2
must be attached to the C-5 hydroxyl group. The
5-O-glycosylation in 2 was further con®rmed by a
comparison of 13C NMR data of 2 with 1 (Table 1)
which showed up®eld shifts of 3.0 and 4.9 ppm for
the C-5 and C-4 resonances, and down®eld shifts of
5.5 and 4.5 ppm for the C-6 and C-10 resonances,
respectively [14]. The coupling constant (J = 7 Hz)
of the anomeric proton signal at d 4.78 indicated
the b-con®guration of the glucopyranoside. Thus, 2
was characterized as echioidinin 5-O-b-D-glucopyra-
noside.
(log E) 257 (4.38), 305 (4.33) and 330 (4.25);
+NaOMe: 257 sh, 300 sh, 400 + NaOAc: 257, 305,
342 sh; +AlCl3: 257, 315, 348 sh; +AlCl3/HCl:
KBr
257, 288 sh, 335; IR n
cm 1: 3200 (OH), 2950,
max
1652 (C.O), 1618, 1560; 1H NMR (DMSO-d6): d
10.70 (OH-2'), 7.94 (1H, dd, J = 2, 8 Hz, H-6'),
7.38 (1H, dt, J = 2, 8 Hz, H-4'), 7.02±7.04 (2H, m,
H-3', 5'), 7.06 (1H, s, H-3), 6.98 (1H, d, J = 2.5 Hz,
H-8), 6.92 (1H, d, J = 2.5 Hz, H-6), 4.78 (1H, d,
J = 7 Hz, H-1 ), 3.91 (3H, s, OMe-7), 3.35±3.85
(5H, m, sugar protons), 13C NMR: Table 1.
Acid hydrolysis of 2
A MeOH soln. of 2 (20 mg) in 2N HCl (5 ml)
heated at 1008 for 1 h gave glucose and (1) (12 mg)
identi®ed by mp, UV, IR, 1H and 13C NMR
analysis.
EXPERIMENTAL
General
Mps: uncorr. UV and IR: MeOH and KBr discs,
respectively. 1H and 13C NMR: 300.13 and
75.43 MHz, respectively in DMSO-d6 and CDCl3
with TMS as int. standard. EIMS at 70 eV (direct
probe). FABMS was registered in positive ion mode
using a glycerol matrix. CC: Silica gel ®ner than
200 mesh (0.08 mm).
Acetylation of 2
A mixture of 2 (10 mg), Ac2O (2 ml) and C5H5 N
(1 ml) was kept at room temp. for 48 h and poured
into crushed ice to yield the penta-acetate of 2 as
colourless crystals (12 mg) from MeOH, mp 1208
KBr
IR n
cm 1: 1760 (C.O of OAc), 1654 (C.O),
max
1619, 1465, 1433, 1369, 1345, 1196; 1H NMR
(CDCl3) d: 7.47 (2H, m, H-4', 6'), 7.12 (1H, m,
H-3'), 6.96 (1H, m, H-5'), 6.67 (1H, d, J = 2.5 Hz,
H-8), 6.63 (1H, d, J = 2.5 Hz, H-6), 6.14 (1H, s,
H-3), 5.08 (1H, d, J = 7 Hz, H-1 ), 5.10-5.19 (4H,
m, H-2 , 3 , 4 , 5 ), 4.19±4.27 (2H, m, CH2-6 ), 3.89
(3H, s, OMe), 2.42 (3H, s, OAc-2'), 1.91±2.08 (12H,
m, 4 ÂOAc).
Plant material
The whole plant of Andrographis alata Nees was
collected from the Talakona hills, Andhra Pradesh,
India, in January 1995. A voucher specimen has
been deposited in the Herbarium of the Department
of Botany, Sri Venkateswara University, Tirupati.
Extraction and isolation
Dried and powdered whole plant (2.5 kg) were
successively extracted with n-hexane, Me2CO and AcknowledgementsÐThe authors thank Dr K.
MeOH. The MeOH extract was defatted with Prabhavathi, Department of Chemistry, Hong