Two novel innovanoside dimers from Daphne aurantiaca and a concise total synthesis of diinnovanoside A

Article abstract of DOI:10.1039/c3cc41811a

Chemical examination of the methanolic extract from the stem bark of Daphne aurantiaca led to the isolation of two innovanoside dimers (1 and 2) with an unusual four-membered cyclobutane ring, together with the isoinnovanoside 3. Their chemical structures and configurations were elucidated by extensive spectral analysis and synthesis.

Full text of DOI:10.1039/c3cc41811a

ChemComm
View Article Online
View Journal | View Issue
COMMUNICATION
Two novel innovanoside dimers from Daphne
aurantiaca and a concise total synthesis of
diinnovanoside A†
Cite this: Chem. Commun., 2013,
49, 6968
Received 11th March 2013,
Accepted 26th April 2013
ab
c
Shuang Liang,z Shan-Xiang Liu,z Hui-Zi Jin,c Lei Shan,a Shi-Chong Yu,d
Yun-Heng Shen,a Hui-Liang Li,a Qiu-Ye Wu,d Qing-Yan Sun*d and
Wei-Dong Zhang*a
DOI: 10.1039/c3cc41811a
www.rsc.org/chemcomm
Chemical examination of the methanolic extract from the stem diffraction as well as other chemical methods. Herein, we have
bark of Daphne aurantiaca led to the isolation of two innovanoside described the structural elucidation, synthetic methods and
dimers (1 and 2) with an unusual four-membered cyclobutane inhibitory activities against LPS-induced NO production in
ring, together with the isoinnovanoside 3. Their chemical struc- macrophages of compounds 1, 2 and 3.
tures and configurations were elucidated by extensive spectral
analysis and synthesis.
The EtOAc-soluble fraction of the methanolic extract from
the stem bark of D. aurantiaca was sequentially subjected to
repeated column chromatographies over silica gel, RP-18, and
Daphne aurantiaca Diels is a common evergreen shrub native to Sephadex LH-20 columns eluting with a variety of different
the Yunnan and Sichuan provinces of China. Its stem bark is solvent systems to afford the two new innovanoside dimers,
used as a traditional folk medicine for the treatment of impact diinnovanosides A and B (1 and 2), as well as the isoinnovano-
injuries sustained from falls such as bruises.1 As part of side (3). By comparing the physical and spectroscopic data of
our ongoing research on thymelaeaceous plants, we recently these compounds with other data reported in the literature,5
developed an interest in studying the chemical constituents of compound 3 was identified to be an isoinnovanoside.
D. aurantiaca and have studied this plant species over the last
Compound 1§ was obtained as a colorless oil. The molecular
3 years.2–4 During the course of this study, two interesting new formula of the material was determined to be C42H44O20 using
innovanoside dimers, diinnovanosides A and B (1 and 2), were HRESIMS, which provided a mass ion of [M ꢀ H]ꢀ at
isolated from the titled plant and were found to contain an m/z 867.2357. The 1H, 13C and DEPT NMR spectra of 1
unusual four-membered cyclobutane ring. Confirmation of the (Table 1) revealed the presence of resonance signals typical of
structural configurations of compounds 1 and 2 proved to be several moieties, including (1) two maltol groups5 [dH 6.43 (1H, d,
particularly challenging only by extensive spectral analyses. J = 5.6 Hz), 7.90 (1H, d, J = 5.6 Hz), 2.32 (3H, s); 6.43 (1H, d,
Based on these difficulties, we developed and implemented a J = 5.6 Hz), 7.96 (1H, d, J = 5.6 Hz), 2.30 (3H, s); dC 164.7, 143.4,
synthetic strategy for the construction of diinnovanoside A (1) 177.1, 117.4, 157.2, 15.9; 164.6, 143.2, 177.0, 117.4, 157.3, 15.9];
to provide further confirmation of its absolute configuration (2) two 4-hydroxyphenyl rings [dH 7.06 (2H, d, J = 8.4 Hz), 6.72
and the relative configuration of 2 using single-crystal X-ray (2H, d, J = 8.4 Hz); 7.04 (2H, d, J = 8.4 Hz), 6.69 (2H, d, J = 8.4 Hz);
dC 130.9, 129.8, 116.3, 157.7, 116.3, 129.8; 130.9, 129.8, 116.3,
157.7, 116.3, 129.8]; (3) two b-glucose moieties5 [dH 4.65 (1H, d,
a Department of Natural Product Chemistry, School of Pharmacy, Second Military
J = 5.6 Hz), 4.78 (1H, d, J = 7.6 Hz); dC 105.0, 75.2, 77.7, 71.4, 76.1,
Medical University, Shanghai 200433, People’s Republic of China.
E-mail: wdzhangy@hotmail.com; Fax: +86-21-81871244; Tel: +86-21-81871244
b Shanghai University of Traditional Chinese Medicine, Engineering Research Center
of Modern Preparation Technology of TCM, Ministry of Education,
Shanghai 201203, People’s Republic of China
64.5; 104.7, 75.2, 77.7, 71.4, 76.0, 64.4]; and (4) two CQO groups
(dC 177.1, 173.4) (Table 1). The structure was further confirmed
by comparison with a very similar NMR spectrum observed for
the corresponding region of isoinnovanoside (3). The 1H–1H
correlations of H-700 (dH 4.25) with H-800 (dH 3.81) and H-80000
(dH 3.78), and of H-70000 (dH 4.20) with H-800 and H-80000 allowed for
the assignment of the cyclobutane ring. The structure of 1 was
consequently established and named diinnovanoside A on the
basis of the HMBC spectroscopic analysis (Fig. 1).
c School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240,
People’s Republic of China
d Department of Organic Chemistry, School of Pharmacy, Second Military Medical
University, Shanghai 200433, People’s Republic of China.
E-mail: sqy_2000@163.com; Fax: +86-21-81871244; Tel: +86-21-81871244
† Electronic supplementary information (ESI) available: Experimental section
and NMR spectra of compounds 1–11. CCDC 907651. For ESI and crystallographic
data in CIF or other electronic format see DOI: 10.1039/c3cc41811a
‡ These authors have contributed equally to this work.
To identify the stereochemistry of compound 1, compounds
1 and 11 were synthesized for the first time according to the
c
6968 Chem. Commun., 2013, 49, 6968--6970
This journal is The Royal Society of Chemistry 2013

View Article Online
Communication
ChemComm
Table 1 13C and 1H NMR spectroscopic dataa for compounds 1 and 2
afford compound 5.7 In a separate sequence, p-coumaric acid
was coupled with TBDMS triflate, and subsequently treated
with 1 N HCl over 24 h to afford compound 6. Compound 6 was
then subjected to a photodimerization reaction to give com-
pound 7, which was coupled with 5 to give compound 8. Finally,
removal of the TBDMS protecting groups of 8 afforded com-
pound 1 in 80% yield.8 The overall yield of 1 was 10.8%.
In a separate sequence, compound 9 was obtained via the
esterification of compound 7 with methanol in the presence of
N1-[(ethylimino)methylene]-N3,N3-dimethylpropane-1,3-diamine
hydrochloride (EDCI) and N,N-dimethylpyridin-4-amine (DMAP).
The TBDMS protecting groups in 9 were then removed with
tetrabutylammonium fluoride (Bu4NF) to give 10. Finally, the
acetylation of 10 provided compound 11. The stereochemistry
of 11 was confirmed by X-ray analysis (Fig. 2). The results
indicated that compound 6 had undergone topochemically
controlled a-dimerization to form the corresponding head-to-
tail adduct 7.
1
2
No.
dC
dH
dC
dH
2
3
4
5
6
7
164.7
143.4
177.1
117.4
157.2
15.9
105.0
75.2
77.7
164.6
143.3
177.1
117.5
157.5
16.1
105.0
75.3
77.8
6.43 (d, 5.6)
7.90 (d, 5.6)
2.32 (s)
4.65 (d, 5.6)
3.32 (m)
3.32 (m)
3.13 (m)
2.99 (m)
4.34 (dd, 12.0, 1.6)
3.70 (dd, 12.0, 7.6)
6.52 (d, 5.6)
8.07 (d, 5.6)
2.40 (s)
4.77 (d, 5.6)
3.29 (m)
3.41 (m)
2.93 (dd, 8.8, 10.0)
2.60 (m)
10
20
30
40
50
60
71.4
76.1
64.5
71.2
76.2
64.4
4.53 (dd, 1.6, 12.0)
4.32 (dd, 5.2, 12.0)
100
130.9
129.8
116.3
157.7
116.3
129.8
42.1
131.2
128.9
116.2
157.3
116.2
128.9
42.4
200
7.06 (d, 8.4)
6.72 (d, 8.4)
6.98 (d, 8.4)
6.66 (d, 8.4)
300
400
500
6.72 (d, 8.4)
7.06 (d, 8.4)
4.25 (dd, 10.4, 7.2)
3.81 (dd, 10.4, 7.2)
6.66 (d, 8.4)
6.98 (d, 8.4)
3.97 (dd, 8.4, 10.4)
3.83 (t, 8.4)
600
700
Compound 2§ was isolated as a colorless oil. Its HRESIMS
(negative ion mode) gave a pseudomolecular ion peak for
[M ꢀ H]ꢀ at m/z 867.2357, corresponding to the molecular
formula C42H44O20. The NMR data of 2 were similar to those of 1,
with similar resonance structures corresponding to the two
maltol groups, two 4-hydroxyphenyl rings, two b-glucose moi-
eties, and a four-membered ring deduced by interpretation of
800
48.8
50.3
900
173.4
164.6
143.2
177.0
117.4
157.3
15.9
104.7
75.2
77.7
174.8
164.6
143.1
177.0
117.2
157.3
15.7
104.6
75.2
77.7
20 0 0
30 0 0
40 0 0
50 0 0
60 0 0
70 0 0
10 0 0 0
20 0 0 0
30 0 0 0
40 0 0 0
50 0 0 0
60 0 0 0
6.43 (d, 5.6)
7.96 (d, 5.6)
2.30 (s)
4.78 (d, 7.6)
3.33 (m)
3.33 (m)
3.13 (m)
3.13 (m)
4.14 (dd, 12.0, 1.6)
3.96 (dd, 12.0, 7.6)
6.37 (d, 5.6)
7.89 (d, 5.6)
2.16 (s)
4.63 (d, 7.6)
3.29 (m)
3.23 (m)
3.34 (m)
1
the 2D NMR spectra of 2 (Table 1). The H–1H COSY correla-
tions of H-700 (dH 3.83) with H-800 (dH 3.97) and H-80000 (dH 3.95),
and of H-70000 (dH 4.10) with H-800 and H-80000 implied the presence
of a four-membered ring similar to that of compound 1, which
suggested that 2 may be a diastereoisomer of 1. The relative
configuration of the four-membered ring was determined using
the NOESY spectrum of compound 2. The NOESY correlation of
H-700 with H-70000 indicated that they existed in the cis-form.
Similarly, the NOESY correlation of H-800 with H-80000, also
indicated that t H-800 and H-80000 existed in the cis-form.
In addition, the NOESY correlations of H-800 and H-20000 (dH 6.93)
with H-80000 and H-200 (dH 6.93) implied that H-800/H-70000 and
H-80000/H-700 were in the trans-form, respectively. Therefore, the
structure of compound 2 was deduced as being (700a, 800b, 70000a,
71.4
76.0
64.4
71.1
76.1
64.2
3.45 (m)
4.23 (dd, 1.6, 12.0)
3.36 (m)
10 0 0 0 0
20 0 0 0 0
30 0 0 0 0
40 0 0 0 0
50 0 0 0 0
60 0 0 0 0
70 0 0 0 0
80 0 0 0 0
90 0 0 0 0
130.9
129.8
116.3
157.7
116.3
129.8
42.4
130.9
128.5
116.2
157.2
116.2
128.5
42.0
7.04 (d, 8.4)
6.69 (d, 8.4)
6.93 (d, 8.4)
6.64 (d, 8.4)
6.69 (d, 8.4)
7.04 (d, 8.4)
4.20 (dd, 10.4, 7.2)
3.78 (dd, 10.4, 7.2)
6.64 (d, 8.4)
6.93 (d, 8.4)
3.95 (dd, 8.4, 10.4)
4.10 (t, 10.4)
48.4
173.1
47.0
172.7
a
Data were recorded in CD3OD at 400 MHz for 1H and 100 MHz for
13C NMR.
8
0000b)-diinnovanoside A, and named diinnovanoside B.
Nitric oxide (NO) plays an important role in the inflammatory
route shown in Scheme 1. The single-crystal X-ray structure of process.9 The isolates from the current study were therefore
11 was obtained as shown in Fig. 2. Compound 4 was prepared tested for their inhibitory activities against LPS-induced NO
according to the reported method.6 The material was then production in RAW 264.7 macrophages using methods that have
reacted with TBDMS triflate, and subsequently selectively been previously reported in the literature.10 Compounds 2 and 3
deprotected to remove the 6-O-TBDMS protecting group to showed potent inhibitory activities against the production of NO
Fig. 1 Structures of compounds 1–3 and key HMBC correlations of compound 1 (H - C).
c
This journal is The Royal Society of Chemistry 2013
Chem. Commun., 2013, 49, 6968--6970 6969

View Article Online
ChemComm
Communication
Scheme 1 Synthesis of compounds 1 and 11.
Notes and references
§ Diinnovanoside A (1): colorless oil (MeOH); UV (MeOH): 259 (2.41),
KBr
231 (2.82); [a]2D0 ꢀ47 (c 0.12, CH3OH); IR n
cmꢀ1: 3392, 2896, 1731,
max
1645, 1615, 1517, 1445, 1255, 1198, 1068, 837 cmꢀ1; for 1H and 13C NMR
spectroscopic data, see Table 1; negative HR-ESIMS, found 867.2354,
calcd 867.2348 for C42H43O20 [M ꢀ H]ꢀ. Diinnovanoside B (2): colorless
oil (MeOH); UV (MeOH): 256 (2.58), 230 (3.34); [a]2D0 ꢀ48 (c 0.08,
KBr
CH3OH); IR n
cmꢀ1: 3419, 2900, 1732, 1646, 1615, 1517, 1455,
max
1255, 1197, 1066, 838 cmꢀ1; for 1H and 13C NMR spectroscopic data,
see Table 1; negative HR-ESIMS, found 867.2354, calcd 867.2348 for
C42H43O20 [M ꢀ H]ꢀ.
Fig. 2 Single-crystal X-ray diffraction of compound 11.
1 C. Z. Gu, Flora Reipubicae Popularis Sinicae, Science Press, Beijing,
1999, vol. 52, pp. 361–364.
2 S. Liang, Y. H. Shen, Y. Feng, J. M. Tian, X. H. Liu, Z. Xiong and
W. D. Zhang, J. Nat. Prod., 2010, 73, 532–535.
3 S. Liang, Y. H. Shen, J. M. Tian, Y. Feng, Z. Xiong and W. D. Zhang,
Helv. Chim. Acta, 2011, 94, 1239–1245.
4 S. Liang, J. M. Tian, Y. Feng, Z. Xiong and W. D. Zhang, Chem.
Pharm. Bull., 2011, 59, 653–656.
5 M. Yasue, N. Kawamura and J. Sakakibara, Chem. Pharm. Bull., 1970,
8, 856–858.
with IC50 values of 0.284 and 0.068 mM, respectively (amino-
guanidine, positive control, IC50 0.048 mM).
This work was supported by program NCET Foundation,
NSFC (grant no. 81230090), and partially supported by the
Global Research Network for Medicinal Plants (GRNMP) and
King Saud University, Shanghai Leading Academic Discipline
Project (B906), FP7-PEOPLE-IRSES-2008 (TCMCANCER Project
230232), Key laboratory of drug research for special environ-
ments, PLA, Shanghai Engineering Research Center for the
Preparation of Bioactive Natural Products (grant no. 10DZ2251300)
and the Scientific Foundation of Shanghai China (grant no.
09DZ1975700, 09DZ1971500, and 10DZ1971700), the National
Major Project of China (grant no. 2011ZX09307-002-03) and the
National Key Technology R&D Program of China (grant no.
2012BAI29B06).
¨
6 L. Kroger and J. Thiem, J. Carbohydr. Chem., 2003, 22, 9–23.
7 M. Y. Chen, K. C. Lu, S. Y. Lee and C. C. Lin, Tetrahedron Lett., 2002,
43, 2777–2780.
8 Y. M. Chi, M. Nakamura, T. Yoshizawa, X. Y. Zhao, W. M. Yan,
F. Hashimoto, J. Kinjo, T. Nohara and S. Sakurada, Biol. Pharm.
Bull., 2005, 28, 1776–1778.
9 J. B. Calixto, M. F. Otuki and A. R. Santos, Planta Med., 2003, 69,
973–983.
10 A. M. Diaz, M. J. Abad, L. Fernandez, A. M. Silvan, J. D. Santos and
P. Bermejo, Life Sci., 2004, 74, 2515–2526.
c
6970 Chem. Commun., 2013, 49, 6968--6970
This journal is The Royal Society of Chemistry 2013