Chemistry of Natural Compounds, Vol. 49, No. 3, July, 2013 [Russian original No. 3, May–June, 2013]
REACTION OF CONVOLVINE AND ADIPIC ACID CHLORIDE
*
I. I. Okhunov and S. F. Aripova
UDC 547.944/945
The majority of plants of the genus Convolvulus (Convolvulaceae) are rich sources of tropane alkaloids. Individual
species of this genus (C. subhirsutus, C. pseudocanthabrica, C. krauseanus) contained at certain vegetative periods from 0.6
to 4.0% total alkaloids [1]. The principal bases in these plant species with respect to total content were the two alkaloids
convolvine and its N-methyl derivative convolamine. The content of the mixture of these two alkaloids in the total reached
70%. A series of compounds were synthesized and their biological activity was studied as a result of the good availability of
convolvine, which is the ester of the amino alcohol nortropine and veratric acid [2].
The previous research found that the alkaloid convolvine and its derivatives exhibited anti-hypoxic, local anesthetic,
anti-inflammatory, and immunomodulating activity [3, 4]. The alkaloids convolvine and convolamine showed antimicrobial
and antifungal activity. This provided a basis for development of the antifungal preparation Consubin, which was proposed
for application in dermatology [5].
In continuation of research in this direction, we synthesized 1 based on the alkaloid convolvine and adipic acid.
The dichloride of the latter was prepared using SOCl and was esterified in toluene in the presence of NEt . The synthesized
2
3
product was purified by column chromatography over Al O .
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3
The IR spectrum of 1 was taken from pressed KBr pellets on a Model 2000 Fourier IR spectrometer (PerkinElmer)
–1
and exhibited absorption bands for CH– and CH – bending vibrations at 2835 cm ; –OCH and C–CH (1357, 1375); an
2
3
3
ester carbonyl conjugated to an aromatic ring at 1702; an amide carbonyl (N–CO) at 1634; an aromatic ring (1602); an ether
(1035), and a 3,4-disubstituted benzene ring (818, 873). The presence in the spectrum of a strong absorption band for an
amide carbonyl indicated that the adipic acid was bonded through the N atom of convolvine.
The PMR spectrum of 1 was recorded on a Unity 400+ spectrometer (Varian) at operating frequency 400 MHz for
protons. Resonances for six aromatic protons were observed at 6.87 (2H, d, J = 9 Hz), 7.25 (2H, d, J = 2 Hz), and 7.36 and
7.38 ppm (1H each, dd, J = 2, J = 9 Hz). Diagnostic resonances for the 3ꢀ-H protons of the tropane core were found at
1
2
5.10 ppm. Two 2H multiplets for the C-1 and C-5 protons of the tropane ring occurred at 4.59 and 4.22 ppm. A singlet for the
four OCH groups of the benzene ring appeared at 3.55 ppm. The region 2.48 ppm contained a multiplet (4H) for the
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CH –C=O protons. The methylenes gave a broad resonance in the range 1.80–2.15 ppm (16H) for the eight methylene
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protons on C-2, C-4, C-6, and C-7 of the tropane core. The CH –CH –C=O protons formed a multiplet at 1.57 ppm.
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2
The spectral characteristics of 1 indicated that the product consisted of two symmetric convolvine molecules bonded
to each other through their N atoms by adipic acid and had the structure bis-(convolvine)amide of 1,6-hexanedioic acid (1).
4'
H CO
OCH
OCH
3
3
3
1
3'
3
N
C
O
(CH )
2 4
C
O
N
C
O
O
O
C
O
1'
H CO
3
5
1
Adipic Acid Chloride. Adipic acid (0.1 g, 0.69 mmol) was treated with SOCl (0.5 mL, excess) and left at room
2
temperature for 1 d. The excess of SOCl was vacuum distilled until it could not be smelled. The residue was an oily liquid.
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Preparation of 1. A mixture of convolvine (100 mg, 0.34 mmol), adipic acid chloride (38 mg, 0.2 mmol), toluene
(5 mL), and NEt (0.1 mL, 0.4 mmol) was refluxed on an oil bath for 3 h. The solvent was vacuum distilled from the reaction
3
mixture. The residue was chromatographed over a column of Al O with elution by CHCl and CHCl :MeOH (9.5:0.5).
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3
3
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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: salima_aripova@mail.ru. Translated from Khimiya Prirodnykh Soedinenii, No. 3,
May–June, 2013, pp. 499–500. Original article submitted February 11, 2013.
©
0009-3130/13/4903-0585 2013 Springer Science+Business Media New York
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