P. Vicini et al. / Il Farmaco 57 (2002) 363–367
365
4. Experimental
White solid (77%), C H N S (293.35); m.p. 201–
15 11 5
2
1
02 °C; IR w max=3120–2380 (NꢀH), 1555 (CꢁN),
230, 1112, 1047 (substituted tetrazole).
4.1. Chemistry
4
.1.2. (1H-Benzimidazol-2-yl)acetic acid (5)
Melting points (°C) were determined with a Buchi
12 (Buchi, Flawil, Switzerland) and are uncorrected.
1
H-Benzimidazol-2-ylacetonitrile (0.02 mol) was
5
added to a solution of water (40 ml) and ethanol (16
ml) containing sodium hydroxide (0.06 mol) and
refluxed until no more ammonia was evolved. The
reaction mixture was evaporated to dryness under re-
duced pressure and the resulting residue was dissolved
in water. The solution, after treatment with decolouriz-
ing carbon, was acidified with acetic acid. After stand-
ing for a long time (30 h) the solid crude product was
filtered off. It was purified by dissolution in sodium
hydoxide aqueous solution (2%) and reprecipitation by
acidification with acetic acid. White solid (93%),
New compounds were analyzed in our analytical labo-
ratory, on a Carlo Erba 1106 Elemental Analyzer
(
Carlo Erba Milan, Italy) for C, H and N. IR spectra
were recorded (KBr pellets) on a Jasco FT-IR 300E
spectrophotometer (Jasco Ltd., Tokyo, Japan). All re-
actions were monitored by TLC on F254 silica gel
precoated sheets (Merck) using acetic acid/ethanol/wa-
ter=1:2:2 for compounds 1, 3, 5 and petroleum ether/
ethyl acetate=3:1 for 2, 4, 6 as eluents. The purified
compounds each showed a single spot. Spectral IR data
were consistent with the assigned structure in all cases
−
1
C H N O (176.17); m.p. 121 °C dec.; IR w max=3393
and the reported wavenumbers are given in cm . The
found values for C, H, N elemental analysis were
9 8 2 2
(
NꢀH), 1644 (CꢁO), 1612 (CꢁN).
9
0.4% of the theoretical ones.
H NMR spectra of the synthetized compounds, in
1
4.1.3. 5-[(1H-Benzimidazol-2-yl)methyl]tetrazole (6)
To a solution of 1H-benzimidazol-2-ylacetonitrile
DMSO-d solutions, were recorded on a Bruker AC 300
instrument at 298 K. Chemical shifts are reported as l
6
(
0.01 mol) in N,N-dimethylformamide (20 ml), ammo-
nium chloride (0.03 mol) and sodium azide (0.03 mol)
were added. The reaction mixture was heated for 5 h at
(
ppm) relative to TMS as internal standard.
1
27 °C, with stirring. After standing overnight at room
4
.1.1. 5-[Benzo[d]isothiazol-3-yl-(phenyl)-
temperature the precipitated sodium chloride was
filtered off and the filtrate was concentrated under
reduced pressure. The residue, added with water (100
ml), was buffered with ammonium chloride saturated
aqueous solution. The resulting precipitate was col-
lected by filtration, dried and crystallized from water.
White solid (86%), C H N (200.19); m.p. 130 °C dec.;
methyl]tetrazole (4)
To a solution of benzo[d]isothiazol-3-ylphenylace-
tonitrile (0.01 mol) in N,N-dimethylformamide (40 ml),
ammonium chloride (0.03 mol) and sodium azide (0.03
mol) were added. The mixture, heated at 127–130 °C,
was vigorously stirred for 5 h. After cooling, it was
concentrated under reduced pressure and the residue
was stirred with water (50–60 ml) and alkalized with 2
N NaOH. A pitchy residue was eliminated and the
solution acidified with 2 N HCl, afforded a crystalline
residue which was crystallized from ethanol/water.
9
8
6
IR w max=3160–2210 (NꢀH), 1575 (CꢁN), 1228, 1110,
1
020 (substituted tetrazole).
1
H NMR spectral data of compounds 1–6 are re-
ported in Table 1.
4.2. Pharmacology
Table 1
1
H NMR spectral data of compounds 1–6
4
.2.1. In 6i6o experiments
Antiphlogistic, analgesic and antipyretic activities
1
Comp.
H NMR (DMSO-d ): l (ppm)
6
were evaluated following the experimental procedures
already described [8]. Briefly, rat paw oedema was
induced through subplantar injection of carrageenan,
and fever was produced in rats with intraperitoneal
injection of E. coli lipopolysaccharide (LPS). The phar-
macological activities of the compounds were expressed
as the percentage of inhibition calculated from the
difference in the response between the treated and the
control group at the time the maximum noxious effect
occurred. Antinociceptive activity was investigated by
studying the dose–response relationship (range of ad-
ministration from 1 to 400 mg/kg o.s.) in writhing test
performed in mice through acetic acid intraperitoneal
injection and by examining the analgesic action in mice
1
10.55 (br s, 1H, COOH); 8.19 (d, 1H, H-7); 8.12 (d,
1
2
H, H-4); 7.61 (t, 1H, H-6); 7.51 (t, 1H, H-5); 4.17 (s,
H, CH2)
2
3
8.24–8.18 (m, 2H, H-4,7); 7.64 (t, 1H, H-6); 7.54 (t, 1H,
H-5); 4.88 (s, 2H, CH2)
10.34 (br s, 1H, COOH); 8.19 (d, 1H, H-7); 8.11 (d,
1
(
H, H-4); 7.59 (t, 1H, H-6); 7.47 (t, 1H, H-5,2%,6%); 7.31
m, 3H, H-3%,4%,5%); 5.87 (s, 1H, CH)
8.23 (d, 1H, H-7); 8.07 (d, 1H, H-4); 7.61 (t, 1H, H-6);
.49–7.45 (m, 3H, H-5,2%,6%); 7.37–7.26 (m, 3H,
4
7
H-3%,4%,5%); 6.80 (s, 1H, CH)
10.25 (br s, 1H, COOH); 7.45–7.42 (m, 2H, H-4,7);
5
6
7
.10–7.07 (m, 2H, H-5,6); 4.05 (s, 2H,CH2)
7.53–7.50 (m, 2H, H-4,7); 7.18–7.15 (m, 2H, H-5,6);
.59 (s, 2H, CH2)
4