Alkaloids from plants of the Nitraria genus. structure of sibiridine

Article abstract of DOI:10.1023/A:1025482821368

The new alkaloid sibiridine was isolated from the aerial parts of Nitraria sibirica and N. schoberi. Its structure was established using spectral data and chemical transformations. Its synthesis was carried out.

Full text of DOI:10.1023/A:1025482821368

Chemistry of Natural Compounds, Vol. 39, No. 3, 2003
ALKALOIDS FROM PLANTS OF THE
STRUCTURE OF SIBIRIDINE
GENUS.
Nitraria
T. S. Tulyaganov and F. Kh. Allaberdiev
UDC 547.944/945
Nitraria sibirica
N. schoberi.
Its
The new alkaloid sibiridine was isolated from the aerial parts of
and
structure was established using spectral data and chemical transformations. Its synthesis was carried out.
Key words:
,
,
, alkaloid, synthesis, sibiridine.
Nitraria N. sibirica N. schoberi
In continuation of the studyof alkaloids from the aerial part of
the benzene fraction of the total bases [1] bycolumn chromatography: C H NN OH , mp 192-193°C, named byus sibiridine.
Pall., the new base 1 was isolated from
Nitraria sibirica
+
-
15 13
The mass spectrum of 1 exhibits peaks with / 222, 221, and 220 in addition to peaks of ions arising from quinoline
m z
and pyridine parts of the molecule [2].
The IR spectrum contains absorption bands at 1665, 1631, 1585, 1538, 1500, 1475, and 1453 (conjugated C=C and
-1
C=N systems) and 865, 843, 807, 776, 767, and 742 cm (out-of-plane deformations of aromatic rings).
The PMR spectrum of 1 has at weak field a complicated group of signals characteristic of aromatic protons.
Sibiridine was found to be identical to one of the dehydrogenation products of dihydroschoberine (2) by Pd-black.
Structure 1 was most probable based on spectral data and the formation from dihydroschoberine via dehydrogenation.
We synthesized a compound of this structure from 8-bromomethylquinoline and pyridine by the scheme given below.
N
N
N
H
+
N
N
N
−
N
OH
CH Br
CH
3
2
2
1
3
4
8-Methylquinoline (3) was synthesized from -toluidine by the Scraup method [3]. 8-Bromomethylquinoline (4) was
o
prepared bybromination of 8-methylquinoline bythe literature method [4]. Alkylation of pyridine by8-bromomethylquinoline
afforded 1, which was identical in physicochemical properties and spectral data to the natural alkaloid sibiridine.
Thus, sibiridine is (quinol-8-yl)methylpyridinium hydroxide and is a new type of nitrogenous base.
1 was also isolated from the benzene fraction of the total alkaloids from
L. collected in June 1995 near
N. schoberi
Ayakhagitm village of Bukhara region of the Republic of Uzbekistan.
EXPERIMENTAL
Information on the instruments used to record spectra, the solvent systems used for TLC, and the conditions for
extraction and separation of total bases have been published [5, 6].
Isolation of Sibiridine (1) from
. Fractions 27-37 after chromatographyof the benzene fraction and mother
N. sibirica
liquorsoffractionsafter separation ofdihydroschoberine [5] were combined and separated chromatographicallyover a silica-gel
S. Yu. Yunusov Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan,
Tashkent, fax (99871) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 228-229, May-June, 2003.
Original article submitted April 21, 2003.
0009-3130/03/3903-0292$25.00 ©2003 Plenum Publishing Corporation
292

column with elution by CHCl :C H OH (9:1). Fractions of 6-7 mL were collected. Fractions 17-21 afforded 1 upon
3
2 5
crystallization from ethanol, 27 mg, mp 192-193°C.
-1
IRspectrum (KBr, ν , cm ): 641, 742, 767, 776, 807, 843, 865, 913, 957, 978, 1000, 1040, 1069, 1131, 1142, 1171,
max
1192, 1216, 1247, 1265, 1321, 1385, 1453, 1475, 1500, 1538, 1585, 1631, 1665, 1708, 2225, 3068, 3128.
UV spectrum (EtOH, λ , nm): 220, 280-295, 307, 320 nm (4.1, 3.51, 3.46, 3.54).
max
+
Mass spectrum, m/z (%): 222, 221 (0.5) [M] , 220 (0.5), 130 (28), 129 (100), 128 (36), 103 (22), 102 (69), 91 (11),
78 (18), 77, 76, 75.
PMR spectrum (CD OD, δ, ppm): 7.85-9.20, 4.8 (br.s).
3
Dehydrogenation of Dihydroschoberine (2) over Pd-black. Dihydroschoberine (37 mg) was mixed with Pd-black
(21 mg). The mixture was immersed into a sand bath heated to 180°C, held for 40 min at 180-200°C, and cooled. The mixture
was dissolved in CHCl :CH OH. The Pd was filtered off. The solvent was distilled off. The solid was worked up as usual and
3
3
chromatographed over a silica-gel column with elution by CHCl :C H OH (10:1). Crystallization of individual fractions from
3
2 5
alcohol isolated base 1 (9 mg), mp 192-193°C.
8-Bromomethylquinoline (4). A suspension of N-bromosuccinimide (1.5 g) in CCl (10 mL) was heated to 60°C,
4
treated in portions with 8-methylquinoline (1.5 g), and boiled for 1 h on a water bath. Upon completion of the reaction, the
insoluble part was filtered off. The filtrate was evaporated. The solid was washed with water. Crystallization from petroleum
ether afforded 4, 0.5 g, mp 83-84°C.
Preparation of 1 from Pyridine and 8-Bromomethylquinoline (4). A solution of pyridine (2 mL) in acetone (5 mL)
was treated in portions with 8-bromomethylquinoline (0.5 g) in acetone (5 mL) and boiled on a water bath for 2 h. The solvent
was removed. Water was added. The solution was made basic with NaOH solution (10%) and extracted with CHCl . The
3
CHCl was evaporated. The solid was crystallized from alcohol. Yield 0.51 g of base 1, mp 192-193°C.
3
Isolation of Sibiridine (1) from N. schoberi. The benzene fraction (14.26 g) of total bases [6] was chromatographed
over a silica-gel column with elution by CHCl :C H OH in various ratios (20:1, 15:1, 10:1, 5:1, and 4:1). Fractions of 40-
3
2 5
50 mL were collected.
The mother liquors of fractions 9-15, 16-21, and 22-29 were combined after isolation of nitraraine, deoxyvasicinone,
and tetramethylenetetrahydro-β-carboline, respectively, and rechromatographed over a silica-gel column with elution by
CHCl :C H OH (6:1). Fractions of 15-20 mL were collected.
3
2 5
After isolation of dihydronitraraine, the mother liquors of fractions 14-21 were separated over a silica-gel column with
elution by CHCl :CH OH (10:1). Fractions of 10-15 mL were collected.
3
3
Removal of solvent from fractions 24-35 and crystallization from alcohol produced 1, 23 mg, mp 192-193°C.
REFERENCES
1.
2.
T. S. Tulyaganov and F. Kh. Allaberdiev, Khim. Prir. Soedin., 479 (2002).
J. H. Beynon, Mass Spectrometry and Its Application to Organic Chemistry, D. Van Nostrand Co., Princeton, N. J.
(1960); H. Budzikiewicz, C. Djerassi, and D. H. Williams, Interpretation of Mass Spectra of Organic Compounds,
Holden-Day, San Francisco (1964).
3.
N. S. Vulf′son, ed., Preparative Organic Chemistry [in Russian], Khim. Lit., Moscow (1959); W. Polaczkowa, ed.,
Preparatyka Organiczna, Panstwowe Wydawnictwa Techniczne, Warsawa (1954).
K. N. Campbell, J. F. Ackerman, and B. K. Campbell, J. Am. Chem. Soc., 71, 2905 (1949).
T. S. Tulyaganov and F. Kh. Allaberdiev, Khim. Prir. Soedin., 476 (2001).
4.
5.
6.
T. S. Tulyaganov and O. M. Nazarov, Khim. Prir. Soedin., 323 (2000).
293