全 文 ：　　　　 天然产物研究与开发　 　　　　　
Vo1.14　No.2 NATU RAL PRODUCT RESEARCH AND DEVELOPMENT　 　　　　　　　
　
　
　
　A NEW BISCHROMAN FROM
SIEGESBECKIA PUBESCENS＊
XIONG Jiang 　XU Yun-long＊＊
(Kunming Institute of Botany , The Chinese Academy of Sciences , Kunming　650204 , China)
Abstract　A new bischroman(1)has been isolated from the diethy l ether ex tract of S iegesbeckia pubescens.
Based on spectral analysis including 2D-NM R techniques , the structure of 1 w as elucidated as 3 , 3 -bis(3 , 4-di-
hydro-6-methoxy-2H-1-benzopyr an)or 3 , 3-bis(6-methoxychroman).
Key words　Siegesbeckia pubescens;3 , 3-bis(3 , 4-dihydro-6-methoxy-2H-1-benzopy ran)
S iegesbeckia pubescens has been used as a traditional
medicine to t reat rheumatic arthri tis ,hypertension in
China[ 1] .In previous papers , we reported ten new
diterpenoids , siegesbeckioside , siegesbeckiol , sieges-
beckic acid[ 2] , orientalin A and B[ 3] , pubeside A ～
E
[ 4] .Bisbenzopyrans rarely occur in nature and only a
few bischromone , bischromenes and bischromanol
have been reported so far f rom natural sources[ 5] .The
present paper described the st ructural determinat ion
of a new bischroman(1)from this plant.
Table 1　1H and 13C NMR assignments of compound 1 in C5D5N and 2 in CDCl3
δC of 1 δH of 1 δC of 2 δH of 2
2 , 2 73.59 t 4.07(dd , 8.37 , 6.68)(ax.) 71.69 t 4.24(dd , 9.1 , 6.8)(ax.)
3.70(dd , 8.37 , 6.14)(eq.) 3.85(dd , 9.1 , 3.8)(eq.)
3 , 3 43.23 d 2.33(m) 54.20 d 3.09(m)
4 , 4 39.26 t 2.58(dd , 13.56 , 8.38)(ax.) 85.92 d 4.73(d , 4.1)
2.76(dd , 13.56 , 5.62)(eq.)
5 , 5 113.35 d 6.90(d, 1.80) 114.36 d 6.87(d , 1.8)
6 , 6 148.67 s 146.76 s
7 , 7 121.95 d 6.83(dd , 7.84 , 1.80) 118.98 d 6.80(dd , 8.1 , 1.8)
8 , 8 116.51 d 7.23(d, 7.84) 108.76 d 6.88(d , 8.1)
9 , 9 146.60 s 145.37 s
10 , 10 132.22 s 132.94 s
6 , 6 -OMe 56.01 q 3.80(s) 56.02 q 3.88(s)
　　收稿日期:2001-01-04　　　修回日期:2001-01-21
　　＊Project S upported by the Applied Basic Research Foundation of
Yunnan Province , China(97C089M)
　　＊＊通讯联系人(Corresponding author)
Compound 1 , colourless needles , mp.112 ～ 113 ℃.
[α] 24D-60.546(MeOH;c 0.331), UV(EtOH)λmax nm
(logε):230(4.10),282(3.78),C20H22O4·H2O based
on its HREI-MS m / z:([ M ·H2O ] + , 344.4066 ,
[ M] + , 326.3914).IRυK Brmax cm-1:3350 , 3050 , 3020 ,
3010 , 1608 , 1600 , 1510 , 1437 , 1427 , 1264 , 1240 ,
1153 ,1035 , and 820 cm-1.Its UV , IR , MS , 1H and
13
C NMR were very similar to those of 3 , 3 -bis(3 ,
4-dihydro-4 -hydroxy-6-methoxy-2 H-1-benzopyran)
(2), and this suggested that 1 and 2 had almost the
same constitution
[ 5] .Its 13C NMR spect ra displayed
the signals for ten carbon atoms , as one methy l , tw o
methylene , two methylene , one methine , three sp[ 2]
CH , and three sp[ 2] quaternary carbon atoms.Appear-
ance of only ten carbons instead of tw enty as implied
7
DOI :10.16333/j.1001-6880.2002.02.002
by the molecular fo rmula C20H22O4 , suggested that 1
is dimeric in nature.Its 1H NMR spectrum marked
only eleven proton signals fo r twenty-tw o protons of
the molecule ,which further st reng thened the fact that
1 exists in a dimeric form.Comparison of the 13C
NMR spect ra of 1 with that of 2 show ed the lack of
hydroxy signals and the upfield shif t of the C-4 and
C-4 signals f rom 85.92 d in 2 to 39.26 t in 1.Thus ,
1 was determined as 3 , 3 -bis (3 , 4-dihydro-6-
methoxy-2H-1-benzopy ran)or 3 , 3 -bis(6-methoxy-
chroman).It s M ass fragments at m/ z =311 [ M-
Me] + ,283[ M-CH3-CO ] + , 189(fragment a), 163
(fragment c , benzopyran monomer)and 137(f rag-
ment b)also strongly suppo rted this elucidations.Sim-
ilar to 2 , in this new bisbenzopy ran , the monomers are
linked w ith each other through equatorial linkage of
C-3 and C-3 .The coupling constants of H-4 and H-2
w ith H-3(J 2ax , 3=6.68 Hz , J 2eq , 3=6.14 Hz , J 4ax ,3 =
8.38 Hz , J 4eq ,3=5.62 Hz)suggested that H-3 is axi-
al.A molecular cry stal H2O exist in 1 by its EI-MS
344[ M·H2O] + signal and IR 3350 cm-1 absorpt ion.
＊Acknowledgement:Authors would like to thank the
staff s of analy tical g roup in the Phy tochemist ry Labo-
ratory ,Kunming Insttute of Bo tany for their measur-
ing the spectral data.
References
1　Y.L.Xu , J.Xiong , Q.D.Jin , S.L.Wang , Research Ad-
vancement o f Siegesbeckia.Natural Product R & D ,
2001 , 13(5):80 ～ 85
2　J.Xiong , Y.B.Ma , Y.L.Xu＊, Diterpenoids from Sieges-
beck ia pubescens.Phy tochemistry , 1992 , 31(3):917 ～ 921
3　J.Xiong , Y.B.Ma , Y.L.Xu＊ , The Constituents of Sieges-
beckia orientalis.Natural Product Sciences , 1997 , 3(1):14
～ 18
4　J.Xiong , Q.D.Jin , Y.L.Xu＊, New diterpenoid g lucosides
from S iegesbeckia pubescens.Chinese Chemical Letters ,
2001 , 12(1):51 ～ 54
5　R.Saleem , S.Faizi , F.Deeba , et al.A New Bisbenzopyran
from Aloe barbadensis Roots.Planta Medica , 1997 , 63(5):
454～ 456
腺梗 莶的新双色满
熊　江　许云龙＊＊
(中国科学院昆明植物研究所　昆明　650204)
摘　要　作者从腺梗 莶的乙醚抽出物中分到一个新的双色满成分 , 基于光谱分析和应用二维核磁共
振技术 ,它的化学结构已被确定为 3 , 3-双(3 , 4-二氢化-6-甲氧基-2H-1-苯并吡喃)或 3 , 3 -双(6-甲氧基
色满)。
关键词　腺梗 莶;3 , 3 - 双(3 , 4-二氢化-6-甲氧基-2H-1-苯并吡喃)
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8　　 天然产物研究与开发 Vo1.14　No.2