1
152
Y.-Y. Xie et al.
signals of two anomeric protons at d 4.67
syl-(1 ! 3)-O-[O-a-L-rhamnopyranosyl-
1 ! 6)]-b-D-glucopyranoside (6), and
two alkaloids, zizyphusine (7) and 6-
0
0
(
(1H, d, J ¼ 9.6 Hz, H-1 ) and 4.29 (1H, d,
J ¼ 7.8 Hz) and 10 protons at d 3.73–3.06
0
0
0
13
together with the C NMR spectral
(2 ,3 -dihydroxyl-4 -hydroxymethyl-tetra-
0
hydrofuran-1 -yl)-cyclopentene[c]pyrrole-
data indicated the presence of two b-D-
glucosyl moieties [16]. The linkage
1
,3-diol (8) (Figure 1). Among them,
00
compound 1 is a new one, whose structure
was elucidated using UV, IR, ESI-TOF-
MS, 1D, and 2D NMR techniques. The
known compounds were identified by
comparing their NMR and MS data with
the reported values [7,12–14].
between the anomeric C-1 and C-6 and
0
0
the interglucosidic linkage between C-2
0
00
and C-1 were determined by the HMBC
0
0
000
00
correlations of H-1 /C-6 and H-1 /C-2 .
The chemical shift value of the anomeric
0
0
carbon C-1 and HMBC correlation
0
0
Compound 1 was isolated as a yellow-
ish amorphous powder. The molecular
formula was determined to be C H O
between H-1 (d 4.67) and C-6
(d 108.8/108.7) indicated that the anome-
C
0
0
ric carbon (C-1 , d 70.8) of b-glucose was
C
4
2
48 23
2
from the [M 2 H] ion peak at m/z
19.2508 in the HR ESI-TOF-MS. The
UV absorption maxima at 216, 262, and
43 nm revealed a flavone skeleton.
connected to C-6 through a C-linkage.
The similar NMR phenomenon to that of
spinosin, i.e. the appearance of serial
separate signals, was observed. It is
proposed that rotational isomers produced
by the rotational barriers 7-OCH3 in
flavones-6-C-glycoside must exist in com-
9
3
A positive reaction in the AlCl reagent
3
suggested that compound 1 was a
hydroxyl-substituted flavonoid. The IR
spectrum showed absorption bands due to
0
00
pound 1 [7]. The downfield shift of C-6
(d 62.9, þ 2.2 ppm) and the upfield shift
2
1
hydroxyl group (3401 cm ), carbonyl
(
C
21
1652 and 1701 cm ), and aromatic ring
000
of C-5 (d 73.2, 23.6 ppm) relative to
C
2
1607, 1510, and 1443 cm ). The paper
1
(
chromatography (PC) analysis of the acid
hydrolysis of compound 1 exhibited only
the corresponding signals of spinosin
0
00
revealed the acylation of C-6 , which is
also supported by the corresponding signals
1
the presence of glucose. The H NMR
000
of 6 -feruloyspinosin (4) [7]. The spinosin
spectrum (600 MHz, DMSO-d ) of 1
6
moiety accounted for a partial molecular
formula of C H O . Thus, the remaining
molecular formula should be C H O as a
indicated six aromatic proton signals due
to aglycone moiety, i.e., a characteristic
singlet signal at d 6.67/6.64 due to the H-3
proton, a singlet at d 6.55/6.42 (1H, s, H-8)
indicating A-ring with three substituents,
2
8 31 15
1
4 17 8
substituent attached to the spinosin group at
0
00
C-6 . The resonances for the carbons and
13
1
protons of the substituent in the H and
C
NMR as well as HSQC spectra included an
0
0
an AA BB aromatic proton system
appearing at d 7.80/7.70 (d, J ¼ 8.4,
ABX aromatic proton system appearing atd
0000
0
0
9
.0 Hz, H-2 , 6 ) and 6.91/6.87 (d,
0
0
6.98 (1H, d, J ¼ 9.0 Hz, H-5 ;
0
J ¼ 8.4, 9.0 Hz, H-3 , 5 ) indicating a C-
dC 112.4/112.0), 7.10 (1H, dd, J ¼ 9.0,
0000
4
3
substituted B-ring [15], and a singlet at d
.86 (3H, s) due to methoxyl protons. The
1.2 Hz, H-6 ; d 122.7) and 7.20 (1H, d,
C
0
000
J ¼ 1.2 Hz, H-2 ; d 114.2/114.4), a
C
resonances for the carbons and protons of
the aglycone and the sugar moiety, except
methoxyl (d 3.66, 3H, s; d 55.4), and a
C
carbonyl (dC 165.3). The IR absorption
21
0
00
000
for those of C-5 and C-6 , as well as the
related protons (Table 1), had a close
resemblance to those of spinosin (3), and
bands at 1701 cm
also proved the
existence of the carbonyl group. These
data together with the HMBCs between
1
0000
0000
0000
0000
they were assigned according to the H and
1
C NMR spectral data [7] for spinosin as
well as its own HSQC spectrum. The
H-6 and C-7 , H-2 and C-7 as well
0000
3
as the proton of methoxyl and C-3
indicated the presence of a vanilloyl moiety