Chemistry of Natural Compounds, Vol. 42, No. 1, 2006
FUROCOUMARINS FROM Prangos ferulacea
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K. A. Eshbakova, A. I. Saidkhodzhaev, K. H. C. Baser,
UDC 547.9:582.89
3
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H. Duman, A. D. Vdovin, and N. D. Abdullaev
Plants of the genus Prangos (Apiaceae) are widely distributed around the world and number more than 30 species [1].
Coumarins were isolated in previous invetigations of plants from this genus [2, 3].
The raw material for our studies was collected in Turkey and until now had not been investigated chemically.
Ground air-dried roots (0.9 kg) were extracted with ethanol three times. The combined alcohol extracts were
condensed, diluted with water in a 1:2 ratio, and worked up with ethylacetate to afford a thick brown extract (65 g), a portion
of which (20 g) was placed on an Al O column and eluted by a benzene:ethylacetate mixture (9:1) followed by an increased
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3
ethylacetate concentration. Fractions (200 mL) were collected.
Four coumarin-likecompoundswereisolated:1, C H O , mp108-109°C; 2, C H O , mp 102-103°C; 3, C H O ,
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4
4
16 14
4
19 20 5
mp 132-140°C; 4, C H O , mp 132-133°C. The IR and PMR spectra and physical constants of 1, 2, and 4 identified them
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6 16 6
as isoimperatorin, imperatorin, and hydroxypeucedanin hydrate [4]. According to the literature, imperatorin exhibits anti-HIV
activity [5].
R
1
O
O
O
R
1
, 2
1
: R = OCH -CH=C(CH ) , R = H
3 2
2
1
2
: R = H, R = OCH -CH=C(CH )
1
2
3 2
The structure of 3 was studied using PMR and 13C NMR spectroscopy with computer analysis of the spectra.
The PMR spectrum of 3 exhibited the following signals: 6.01 (1H, d, J = 10 Hz, H-3), 7.52 (1H, d, J = 10 Hz, H-4),
.55 (1H, s, H-5), 7.16 (1H, s, H-8), 3.13 (2H, d, J = 9 Hz, H-1′), 5.05 (1H, t, J = 9 Hz, H-2′), 1.42 (3H, s, H-4′), 1.51 (3H, s,
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H-5′) and signals for senecionic acid at 1.80* (3H, d, J = 1.5 Hz, H-4′′), 2.03* (3H, d, J = 1.5 Hz, H-5′′), and 5.44 (1H, m, H-2′′).
A double-resonance experiment showed spin—spin coupling between H-1′ and H-2′. An Overhauser effect on H-5′ was not
observed with additional irradiation of methyl protons H-4′ and H-5′.
Base hydrolysis of 3 produced the hydroxycoumarin marmesin, the PMR spectrum of which exhibited the following
signals: 6.14 (1H, d, J = 9 Hz, H-3), 7.86 (1H, d, J = 9 Hz, H-4), 6.71 (1H, s, H-5), 7.42 (1H, br. s, H-8), 3.12 (2H, d, J = 9 Hz,
H-1′), 4.65 (1H, t, J = 9 Hz, H-2′), 1.09 (6H, s, H-4′, H-5′). The PMR spectra of 3 and its hydrolysis product showed no direct
acylation effect, which was consistent with the ester in 3 on a quaternary C atom.
The 13C NMR spectrum of 3 contained 18 signals (the two signals for C-4′ and C-5′ had the same chemical shifts).
Signals were assigned based on calculations using the program ACD CNMR. First the molecular geometry was optimized.
Then the chemical shifts were calculated. Table 1 gives the calculations, the assignments, and the absolute values of the
differences between the calculated and observed signals. The maximum deviations between the calculated and experimental
values in the corresponding pairs were observed for the quaternary C atoms.
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) S. Yu. Yunusov Institute of the Chemistryof Plant Substances, Academy of Sciences of the Republic of Uzbekistan,
Tashkent, fax (99871) 120 64 75, e-mail: e_komila@yahoo.com; 2) Anadolu University, Faculty of Pharmacy, Department of
Pharmacognosy, 26470, Eskisehir, Turkey; 3) Gazi University, Faculty of Science and Letters, Department of Biology, 06500,
Ankara, Turkey. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 83-84, January-February, 2006. Original article
submitted September 5, 2005.
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009-3130/06/4201-0102 2006 Springer Science+Business Media, Inc.
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