Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1993-02-19
1994-09-20
Chan, Nicky
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D30940
Patent
active
053490703
DESCRIPTION:
DESCRIPTION
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a novel salicylic acid-maltol conjugates of the formula I and methods for preparing I. ##STR2## wherein R represents H, alkyl groups containing C.sub.1-5 carbon atoms or alkanoyl groups containing C.sub.1-5 carbon atoms. R.sub.1 represents H or alkyl groups containing C.sub.1-5 carbon atoms.
Acetylsalicylic acid (aspirin) shows antipyretic, antianalgesic, antioxidant and antithromobotic activities. However, it induces gastric ulceration.
Maltol derivatives II are components of Panax ginseng and their structures are as follows: ##STR3## wherein R.sub.1 is as previously defined. Maltol derivatives have been shown to exhibit antioxidant activities. Salicylic acid has been used as a keratolytic agent and a food preservative.
The present invention follows the observations that the novel maltol esters of salicylic acid derivatives show no salicylate-induced gastric ulceration activity, whereas exhibit antioxidant and antithrombotic activities to a greater extent than salicylic acid derivatives.
Therefore, the purpose of the presented invention is to provide the novel of the formula I which exhibit aforementioned pharmacological activities and little side effects.
The present invention also provides the synthetic methods of compounds I. Compounds of the formula I are prepared with esterficiation of maltol derivatives II and salicylic acid derivatives III as follows: ##STR4## wherein R and R.sub.1 are as described above and M is -H or an alkali metal.
The esterification of II with III can be done in the presence of either alkyl halides such as chloroform, methylenechloride and ethylenechloride, or amides such as formamide and acetamide, or ethers such as tetrahydrofuran and dioxane, or other organic solvents.
It is desirable to activate the carboxyl group of III. The activation can be achieved by treating III with halogenation agents to make acid halides or by other well-known methods used in organic synthesis.
The reaction of II with III which contains a carboxyl group can be carried out in the presence of diamines such as N,N-dicyclohexylcarbodiimide or other esterification agents used in organic synthesis.
In case free acids are produced in the activation of the carboxyl group, the esterification should be conducted in the presence of tertiary amines or alkalis to remove the free acids.
The reaction is proceeded at the temperature ranging from 0.degree. C. to the b.p. of the solvent employed. The reaction usually goes to completion in 30 min to 48 hrs.
The present invention will now be described with the following examples and tests.
EXAMPLE 1
Acetylsalicylic acid (18.0 g, 0.10 mole), maltol (12.6 g, 0.10 mole), N,N-dicyclohexylcarbodiimide (22.7 g, 0.11 mole) were dissolved in 100 ml of methylenechloride and the solution was stirred for 6 hrs at room temperature.
After removing N,N-dicyclohexylurea by filtration, the filtrate was washed sequantially with water, 5% acetic acid and water. The solution was then dried with Na.sub.2 SO.sub.4. Following filtration and concentration, the needle crystal of maltol-acetylsalicylate ester (compound A) was obtained in n-hexane/ethanol (1:3). NMR spectrum is shown in FIG. 1.
mp: approximately 105.degree. C.
MS [m/z]:288(M.sup.+), 246(C.sub.13 H.sub.10 O.sub.5), 121(C.sub.7 H.sub.5 O.sub.2).
.sup.1 H NMR (CDCl.sub.3) [.delta. ppm]:8.21(1H, dd, J=1.9, 7.7), 8.07(1H, d, J=5.7), 7/74(1H, dt, J=1.9, 7.7), 7.43(1H, dt, J=1.3, 7.7), 7.24(1H, dd, J=1.3, 7.7) 6.48(1H, d, J=5.6), 2.32(3H, s), 2.25(3H, s).
EXAMPLE 2
Maltol-salicylate ester was obtained following the method of Example 1. NMR spectrum is shown in FIG. 2.
mp: approximately 99.degree. C.
EXAMPLE 3
Enzymetic Method of Maltol-Salicylate Ester Preparation
An aceton powder (1.8 g) of rat livers was suspended in 50 ml of 0.1M phosphate buffer (pH 7.4) and stirred for 12 hrs at 4.degree. C. The resulting suspension was centrifuged at 8,000 rpm for 5 min. To 10 ml of supernatant thus obtained was added 30 ml of 10% Tween-30 solution containing ma
REFERENCES:
patent: 5075461 (1991-12-01), Wild
Pedersen, et al. The New England Journal of Medicine, 311(19):1207-1211 (1984).
H. J. M. Barnett Stroke, 21(suppl IV):IV-40-IV-43 (1990).
B. Han et al. Korean Biochem. J. 18(4):337-340 (1985).
A. J. Cameron Mayo Clinic Proceedings, vol. 50: 565-570 (1975).
Manekar et al. Indian J. Med. Res., 71:926-932 (1980).
K. D. Rainsford, Br. J. exp. Path., 58:215 (1977).
H. W. Davenport Gastroenterology, 46(3):245-253 (1964).
LandOfFree
Salicylic acid-maltol conjugates does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Salicylic acid-maltol conjugates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Salicylic acid-maltol conjugates will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2429999