Reaction between p-cresol and camphene
Russ. Chem. Bull., Int. Ed., Vol. 68, No. 5, May, 2019
997
The synthesized compounds were examined partially using
the equipment of the Center for Collective Use "Chemistry" of
the Institute of Chemistry, Komi Scientific Center, Ural Branch
of the Russian Academy of Sciences.
maximum in the wavelength range 515—520 nm, which progres-
sively decreases and disappears when the compound is trans-
formed into the nonradical form. The kinetic curve of changing
the absorbances of the control and experimental samples was
recorded on a Varian Cary 50 spectrophotometer (Australia)
Alkylation of p-cresol with camphene. p-Cresol (2, 1.09 g,
1
0.08 mmol) was heated to 180 °С, and aluminum chip (7.7 mg,
immediately after mixing a solution of DPPH (0.25 mmol L–1
)
0
.29 mmol) was added by small portions. After the complete
with the solvent (control sample) or a solution of the studied
–
1
interaction of the components, the solution was cooled to ∼40 °С
and camphene (2.52 g, 18.49 mmol) was added. The reaction
mixture was stirred at 180 °С under argon for 4 h. After the reac-
tion completion, the mixture was cooled down and diluted with
compound (0.25 mmol L ) (experimental samples) in a ratio of
1 : 1 (vol/vol). Thus, the final concentrations of DPPH and the
studied substance in the samples were 0.125 mmol L–1. Ethanol
served as the solvent. The effective time parameter (ET50%) was
used for the quantitative estimation of the antiradical activity.
Study of pharmacological activity. Acute toxicity of the
sample in each dose was studied for 10 CD-1 mice (5 female and
5 males 18—22 g each). The animals were observed for 14 days,
and the observation was permanent within the first day. The
Litchfield—Wilcoxon probit analysis was used to determine the
Et O, neutral Al O (0.1 g) and active carbon (0.01 g) were
2
2
3
added, and the mixture was stirred for 30 min and left to settle.
The sorbents were filtered off and washed with Et O, and the
2
solvent was removed under reduced pressure. The reaction prod-
ucts (3.5 g) were separated by flash chromatography. Isomers of
3
were separated by crystallization from EtOH. The obtained
diastereomers were assigned to the meso-form and racemate using
chiral HPLC.
acute toxicity parameter LD50.
The study of the hemorheological, membrane-stabilizing,
antiplatelet, and endothelial-protective activity of compound
meso-3 was performed for 21 outbred conventional female SD
rats 220—250 g in weight obtained from the Laboratory of
Experimental Biological Models at the Goldberg Research
Institute of Pharmacology and Regenerative Medicine (Tomsk
National Research Medical Center of the Russian Academy of
Sciences). The studies were carried out obeying humanity prin-
ciples according to the European Convention for the Protection
of Vertebrate Animals used for Experimental and Other Scientific
Purposes (Strasbourg, 1986). Animals were kept under the light
conditions for 12 h with free access to water and food. The dia-
betes model was reproduced in 16 animals with the single intra-
4
-Methyl-2,6-bis{(1S,2R,4R)-1,7,7-trimethylbicyclo[2.2.1]-
hept-2-yl}phenol and 4-methyl-2,6-bis{(1R,2S,4S)-1,7,7-tri-
methylbicyclo[2.2.1]hept-2-yl}phenol (rac-3). Colorless powder,
m.p. 167—169 °С. The yield was 0.84 g (24%). Retention time
1
(
HPLC): 3.5 and 4.3 min. IR (KBr), ν/cm– : 3606 (ОН); 2947
(
CH , СН ); 1608 (С=С); 1179 (=С—O); 868, 787 (=С—Н).
3 2
1
Н NMR (CDCl ), δ: 0.78 (s, 6 Н, С(10)Н , С(10´)Н ); 0.88
3
3
3
(
s, 6 Н, С(9)Н , С(9´)Н ); 0.93 (s, 6 Н, С(8)Н , С(8´)Н );
3 3 3 3
1
.40—1.50 (m, 4 Н, Н(5), Н(5´), Н(6), Н(6´)); 1.58—1.71 (m,
4
Н, Н(3), Н(3´), Н(6), Н(6´)); 1.89—1.90 (m, 4 Н, Н(5), Н(5´),
Н(4), Н(4´)); 2.22—2.31 (m, 2 Н, Н(3), Н(3´)); 2.31 (s, 3 Н,
С(17)Н ); 3.08 (t, 2 Н, Н(2), Н(2´), J = 9 Hz); 4.64 (s, 1 Н,
3
13
–1
ОН); 6.99 (s, 2 Н, Н(14), Н(16)). C NMR (CDCl ), δ: 12.44
С(10), С(10´)); 20.32 (С(9), С(9´)); 21.46 (С(17)); 21.46 (С(8),
gastric administration of streptozotocin in a dose of 40 mg kg
3
3
5
(
in a citrate buffer (pH 4). The animals with the glucose level
–
1
С(8´)); 27.60 (С(5), С(5´)); 34.40 (С(3), С(3´)); 40.14 (С(6),
С(6´)); 45.56 (С(2), С(2´)); 46.16 (С(4), С(4´)); 48.17 (С(1),
С(1´)); 49.61 (С(7), С(7´)); 125.95 (С(14), С(16)); 127.39, 128.23
in the blood from 21 to 25 mmol L was selected for experi-
ment. The glucose level in the whole blood was measured with
a SmartScan glucometer (Lifescan, USA). During the next month,
the starch mucus (1 mL) was daily intragastrically administrated
to animals of the control group (n = 8) and to intact animals
(n = 5), whereas compound meso-3 in a dose of 100 mg kg–1 as
a suspension in the equivolume amount of starch mucus was
administrated to rats of the experimental group (n = 8). An hour
after the last administration, the endothelial function was stud-
ied and blood samples were taken for further studies for the
(
С(11), С(13)); 151.60 (С(12)).
-Methyl-2-{(1S,2R,4R)-1,7,7-trimethylbicyclo[2.2.1]hept-
-yl}-6-{(1R,2S,4S)-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl}-
4
2
phenol (meso-3). Colorless powder, m.p. 204—206 °С. The yield
was 1.75 g (50%). Retention time (HPLC): 7.1 min. The purity
of meso-3 was 98.5%, and rac-3 is 1.5% impurity. IR (KBr),
–
1
ν/cm : 3583 and 3525 (ОН); 2949 (CH , СН ); 1606 (С=С);
3
2
1
–1
1
190 (=C—O); 866 and 788 (=С—Н). Н NMR (CDCl ), δ:
animals under thiopental anaesthesia (60 mg kg ).
3
0
.85 (s, 6 Н, С(10)Н , С(10´)Н ); 0.89 (s, 6 Н, С(9)Н ,
To study the hemorheological activity of compound meso-3,
the blood was samples from the general carotid artery under
3
3
3
С(9´)Н ); 0.95 (s, 6 Н, С(8)Н , С(8´)Н ); 1.40—1.51 (m, 4 Н,
3
3
3
–
1
Н(5), Н(5´), Н(6), Н(6´)); 1.58—1.73 (m, 4 Н, Н(3), Н(3´),
anaesthesia (sodium thiopental, 60 mg kg , intraperitoneally).
A 3.8% solution of sodium citrate in the volume ratio to the blood
1 : 9 was used as an anticoagulant. The viscosity of the whole
blood, haematocrite, fibrinogen concentration in the blood
plasma, plasma viscosity, ability of erythrocytes to spontaneous
aggregation, and erythrocyte deformability were estimated.
The viscosity of the whole blood was measured on a Brookfield
DV–II+Pro rotary viscosimetry (Brookfield Engineering Labs
Inc., USA) with the cone/plate system at 36 °С in the range of
Н(6), Н(6´)); 1.90—1.93 (m, 4 Н, Н(5), Н(5´), Н(4), Н(4´));
2
.30—2.33 (m, 2 Н, Н(3), Н(3´)); 2.33 (s, 3 Н, С(17)Н ); 3.03
3
(
t, 2 Н, Н(2), Н(2´), J = 9 Hz); 4.70 (s, 1 Н, ОН); 7.00 (s, 2 Н,
13
Н(14), Н(16)). C NMR (CDCl ), δ: 12.49 (С(10), С(10´));
3
2
0.24 (С(9), С(9´)); 21.44 (С(17)); 21.44 (С(8), С(8´)); 27.57
(
(
(
С(5), С(5´)); 33.91 (С(3), С(3´)); 40.02 (С(6), С(6´)); 45.47
С(2), С(2´)); 46.10 (С(4), С(4´)); 48.18 (С(1), С(1´)); 49.91
С(7), С(7´)); 125.94 (С(14), С(16)); 127.37 and 128.25 (С(11),
–
1
С(13)); 151.62 (С(12)).
shear rates from 15 to 450 s , and the plasma viscosity was
–
1
The spectral characteristics of compounds 4—9 correspond
measured at a shear rate of 450 s . Erythrocyte aggregation was
to those described previously.33
evaluated under shear flow conditions. Erythrocyte deform-
36
Antiradical activity of compounds meso-3 and rac-3 was
evaluated by their ability to react with DPPH.34 In the visible
spectral range, DPPH in organic solvents has an absorption
ability was estimated by the ektacytometry method in the range
37
of shear stress 1—7 Pa. Erythrocyte aggregation and deform-
ability were studied on a RheoScan-AnD 300 analyzer (Rheo-