N-, O-beta-D-Glucopyranosides of 5-Aminosalicylic Acid
325
Methyl 2-Acetoxy-5-nitrobenzoate (21)
(1H, dd, meta-aromatic proton), 4.9–5.1 (5H, m, 4 OH and anomeric H-1),
4.2–4.46 (2H, m), 3.78 (3H, COOCH3), 3.7 (1H, m), 3.5 (1H, m), 3.1–3.3
(4H, m).
To a solution of 20 (1.79 g, 0.01 mol) in acetic anhydride (20 ml) four
drops of concentrated sulfuric acid were added, and the reaction mixture was
heated on a steam bath with exclusion of humidityfor 3 h. The brown solution
was then poured onto crushed ice (400 g), the brown precipitate was filtered
off and air-dried. The crude product (2.30 g) was crystallized from ether-pe-
troleum ether to obtain pure 21 (1.99 g, 83.2%), mp = 73–74 °C, Rf = 0.86
(solvent mixture A). Anal. C10H9NO6 C, H, N.
Acute Toxicity
The approximate acute toxicity of 5-ASA (2), and its glucosylated deriva-
tives 24 and 28 was determined on a group of 10 CFLP mice/dose according
to the method described by Turner.[30] The reference material was 5-ASA
(2), purchased from Nobel Chemicals, and the LD50 values were calculated
according to Litchfield and Wilcoxson.[36]
.
Methyl 2-Acetoxy-5-aminobenzoate (22)
A mixture of 10% palladium-on-carbon catalyst (0.53 g) in abs. methanol
(20 ml) was saturated with hydrogen gas, a solution of 21 (3.41 g, 0.014 mol)
in abs. methanol (100 ml) was added, and the mixture was hydrogenated
under atmospheric pressure for 3.5 h. The catalyst was then filtered off, the
filtrate was concentrated under diminished pressure, and the residue was
crystallized from hot water (60 ml) with decolorization with charcoal. The
product was dried (IR lamp) to obtain 2.04 g (67.54%) of pure 22, mp = 103–
105 °C, Rf = 0.57 (solvent mixture A). Anal. C10H11NO4 C, H, N.
Induction of Gastric Ulcer
Male Sprague-Dawley rats of 180–250 g were housed at controlled room
temperature and humidity (20–22 °C, 45–60% relative humidity), and fed
with a standard diet of laboratory chow and tap water. The animals were
fasted for 18 h before drug administration, but allowed free access to water.
The indomethacin-type ulcer method was employed[31,32]: 30 mg/kg In-
domethacin (Sigma) prepared in 0.9% NaCl, was administrated orally to the
animals. The ulcerogenic challenge was given 30 min after either saline
administration (control group), or administration of the test substances
prepared in 0.9% NaCl (treated groups), intraperitonally.
Methyl 2-Acetoxy-5-(β-D-glucopyranosylamino)benzoate (24)
To a solution of 22 (1.04 g, 5 mmol) in abs. methanol (150 ml) pre-dried
23 (0.90 g, 5 mmol) and ammonium chloride (0.08 g, 1.5 mmol) were added,
and the mixture was boiled under reflux for 10 h. It was then decolorized
with charcoal, filtered, concentrated under reduced pressure, and the residue
was purified by column chromatography (solvent system E). The combined
eluate was evaporated, and the residue was crystallized from a mixture of
chloroform, ether, and petroleum ether to isolate 24 as pale yellow plates,
yield: 0.84 g (46.9%). Mp = 153–155 °C, [α]D23= –84.4o (c = 0.64, H2O),
Rf = 0.18 (solvent mixture C). Anal. C15H21NO9 C, H, N. lH NMR (DMSO-
d6-D2O) δ: 7.23 (1H, m, Hc), 6.62 (1H, d, NH), 5.0 (1H, d, OH), 4.90 (2H,
t, OH), 4.46 (1H, t, OH), 4.36 (1H, t, H-1, J1,2=8.5 Hz), 3.75 (3H, s,
COOCH3), 3.62–3.10 (6H, m, H-2, H-3, H-4, H-5, H-6a, H-6b), 2.20 (3H, s,
OC-CH3).
After 4 h indomethacin treatment, the animals were killed by ether anaes-
thesia. The stomach was removed and dissected along the greater curvature
under an illuminated magnifier. The mucosal damage was macroscopically
examined and expressed in terms of the ulcer index, which was calculated
according to the method [32] of Rainsford: i.e. ulcer index = mean of lesion
number + stomach lesion severity + ulcer incidence. The severity of lesions
was scored from 0–4 on an artificial scale: 0 = no ulcer; 1 = superficial
mucosal lesion; 2 = deep ulcer; 3 = long and deep ulcer; 4 = penetrating
ulcer. Inhibition % was calculated on the basis of reduction in ulcer index
between the control and treated groups.
References
[1] H. Takai, M. Yoshida, T. Iida, I. Matsubara, K. Shiramata, J. Antib.
1976, 29, 1253–1257.
Methyl 2-(2′,3′,4′,6′-tetra-O-acetyl-β-D-glucopyranosyl-oxy)-5-nitrobenzo-
ate (26)
[2] T. Sasaki, K. Furimata, H. Nakayama, H. Seto, N. Otake, Tetrahedron
Lett. 1981, 27, 1603–1607
To a homogenized mixture of 20 (3.94 g, 0.02 mol), 25 (16.44 g, 0.04 mol)
and activated silver oxide (9.25 g, 0.04 mol) quinoline (15 ml) was added,
the mixture was vigorously stirred together, whereupon it solidified in an
exothermic reaction. After 1 h, the mass was homogenized with glacial acetic
acid (100 ml), and the brown suspension was poured onto crushed ice. The
precipitate was filtered off, washed with ice-water, dried and crystallized
from ethanol (170 ml) to yield 5.24 g (49.7%) of pure 26 as yellow crystals.
Mp = 163–165 °C, [α]D23 = –36.8o (c = 0.8, CHCl3), Rf = 0.70 (solvent mix-
ture A). Anal. C22H25NO15 C, H, N. 1H NMR (CDCl3) δ: 8.68 (1H, d, Hc),
8.35 (1H, dd, Hb), 7.25 (1H, d, Ha), 5.50–5.13 (4H, m, H-1, H-2, H-3, H-4),
4.25 (2H, m, H-6a, H-6b), 4.03 (1H, m, H-5), 3.95 (3H, s, OCH3), 2.07 (12H,
4s, CO-CH3).
[3] H. H. Wasserman, R. J. Gambale, J. Am. Chem. Soc. 1985, 107,
1423–1424.
[4] M. Konishi, H. Ohkuma, K. Saitoh, H. Kawaguchi, J. Antib. 1985, 38,
1605–1609.
[5] M. Prudhomme, G. Dauphin, G. Jeminet, J. Antib. 1986, 39, 923–933.
[6] M. A. Peppercorn, P. Goldman, J. Pharm. Exp. Ther. 1972, 181,
595–598.
[7] A. K. A. Khan, G. Guthrie, H. H. Johnstone, S. C. Truelove, D. H.
Williamson, Clin. Sci. 1983, 64, 349–354.
[8] A. K. A. Khan, J. Piris, S. C. Truelove, Lancet, 1977, 2, 892–895.
Methyl 2-(β-D-glucopyranosyl-oxy)-5-aminobenzoate (28)
[9] S. N. Rasmussen, V. Binder, K. Maier, S. Bondesen, C. Fischer, V.
Klotz, S. H. Hansen, E. F. Hridberg, Gastroenterology, 1983, 85,
1350–1353.
A mixture of 10% palladium-on-carbon catalyst (0.18 g) in ethyl acetate
(10 ml) was saturated with hydrogen gas, a solution of 26 (1.2 g, 2.28 mmol)
in ethyl acetate (40 ml) was added, and hydrogenation was continued at
atmospheric pressure for 3 h. The mixture was then filtered, concentrated
under diminishedpressure, andthesyrupyresidue was crystallizedformethyl
acetate-petroleum ether to yield pure 27 (1.09 g, 96.46%), mp = 138 °C,
[10] K. H. Agback, R. E.Lindbolm, E. Rangvald, DBP. 2257629. 1971
(November 26).
[11] T. M. Parkinson, J. P. Brown, R. E. Wingard, USP. 4190716. 1980
23
[α]D = –25.2° (c = 0.5, CHCl3), Rf = 0.32 (solvent mixture A). Anal.
(February 26).
C
22H27NO12 C, H, N.
[12] CH. 632.670. 1977.
The product 27 (2.90 g, 5.83 mmol) was dissolved in abs. methanol
(150 ml) and 15 drops of a 1 M sodium methoxide solution in methanol was
added. After 1 h, the mixture was adjusted to ca. pH 6, decolorized with
charcoal, and concentrated to ca. 15 ml under reduced pressure. Storage of
the solution at +4 °C resulted in crystallization of 28; it was filtered off and
dried under reduced pressure. Yield: 1.44 g (75%), mp = 156 °C (in a capil-
lary tube), [α]D23 = –43.7o (c = 0.54, H2O), Rf = 0.47 (solvent mixture B).
Anal. C14H19NO8 C, H, N. 1H NMR (DMSO-d6): δ: 7.05 (1H, d, ortho-aro-
matic proton, J1,2 = 8 Hz), 6.9 (1H, d, meta-aromatic proton, J1,2 = 2 Hz), 6.7
[13] H. Rokos, H. Konczak, W. Forth, DBP. 3323702. 1983 (January 7).
[14] E. Evans, DBP. 722795. 1950 (July 31).
[15] L. H. Sarett, W. W. Ruyle, GBP. 1359560. 1972 (February 25).
[16] E. Bouley, J. M. Teulon, M. Cazes, A. Cloarec, R. Deghenghi, J. Med.
Chem. 1986, 29, 100–103.
[17] W. F. Stenson, E. Lobos, Biochem. Pharmacol. 1983, 32, 2205–2209.
Arch. Pharm. Pharm. Med. Chem. 332, 321–326 (1999)