2011 Springer Science+Business Media, Inc.
Chemistry of Natural Compounds, Vol. 47, No. 1, 2011 [Russian original No. 1, January–February, 2011]
STRUCTURE OF A NEW STEROID 24S-ERGOST-4-EN-3,6-DIONE
FROM Aconitum septentrionale
K. A. Eshbakova,
B. Tashkhodzhaev, Zh. I. Tursunov, UDC 548.737+547.918:547.926
K. K. Turgunov, Kh. M. Bobakulov, and N. D. Abdullaev
E-Sitosterol and the new phytosteroid 24S-ergost-4-en-3,6-dione were isolated from the industrial extraction
waste of the alkaloid-bearing plant Aconitum septentrionale Koelle. The structure of the isolated compound
was determined by x-ray structure analysis and PMR,
C NMR, and IR spectroscopy. The crystal structure
of the steroid contains a disordered terminal 24-methyl,24-isopropyl group that occupies two positions in a
Keywords: steroids, 24S-ergost-4-en-3,6-dione, absolute configuration, x-ray crystal structure.
Industrial wastes from targeted extraction of plant drugs may turn out to be useful alternate sources of natural steroids
for scientific and practical purposes. In particular, a large quantity of the alkaloid-bearing plant Aconitum septentrionale
Koelle is extracted at the pilot plant at the Institute of the Chemistry of Plant Substances in order to obtain the drug substance
allapinin [1, 2]. The plant contains in addition to alkaloids [3, 4] organic acids , coumarins , and flavonoids ; the
seeds, essential oils .
These wastes were separated by column chromatography using extraction benzine in order to isolate useful neutral
substances. Separation of the benzine fraction over a column of silica gel isolated
O, mp 135–137°C
. Further elution of the column isolated an ergostane-type diketosteroid 1.
The IR spectrum of 1 had absorption bands characteristic of C–H (2962 cm
(2871), C=O (1688), and C=C
(1603, 1463) groups.
The PMR spectrum (Table 1) showed at strong field two 3H singlets of angular methyl C-18 (0.68 ppm) and C-19
(1.03) in addition to four 3H doublets of secondary methyls C-21 (0.86, SSCC 6.4 Hz) and C-26 and C-27 (0.77, 6.8), and
C-28 (0.87, 8.4). An olefinic proton coupled to a carbonyl was observed as a singlet at 5.96.
C NMR spectrum exhibited 28 resonances. Of these, two appeared at weak field characteristic of ketones. An
analysis of all results using DEPT suggested that the isolated compound was a '
A diketosteroid of similar structure was described earlier from Stephania cepharantha  and from soy culture 
based on GC–MS analysis. Of course, the configuration of the C-24 atom was not determined. Therefore, that compound
could not be matched with the diketosteroid 1 isolated by us.
The structure of the isolated steroid was reliably established based on an x-ray crystal structure analysis (XSA).
Figure 1 shows the molecular structure of 1 from the XSA. A rotational conformer (along the C-23–C-24 bond) was observed
in the crystal structure because of disorder at the terminal 24-methyl and 24-isopropyl groups. Atoms C-25, C-26, C-27, and
C-28 had large thermal parameters and were fixed in two positions in a 0.55:0.45 ratio. Figure 1 shows the disordered atoms
with additional unshaded bonds.
Considering the (8S,9S,10R,13R,14S,17R)-stereochemistry of 1 from the given molecular structure, asymmetric
C-20 and C-24 had the 20R,24S configurations. As expected, rings B/C and C/D were trans-fused. The C-10 and C-13
methyls were situated in
S. Yu. Yunusov Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan,
Tashkent, fax (99871) 120 64 75, e-mail: email@example.com. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp.
66–68, January–February, 2011. Original article submitted June 14, 2010.