Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Patent
1995-05-11
1997-02-11
Richter, Johann
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C07C31139, C07C30344
Patent
active
056022816
DESCRIPTION:
BRIEF SUMMARY
This is a U.S. national stage application under 35 U.S.C. .sctn.371 based upon PCT International Application No. PCT/RU93/0024, filed on Nov. 16, 1993.
FIELD OF ENGINEERING
The present invention relates to organic chemistry, more particularly to a process for preparing a physically stable crystalline .gamma.-modification of para-aminobenzenesulfonamide.
PRIOR ART
It is well known that para-aminobenzenesulfonamide may crystalline at least in three polymorphous modifications designed as .alpha.-, .beta.- and .gamma.forms (Journal of Pharmaceutical Sciences, v. 59, No. 7, July 1970, p. 972-975; Journal of Pharmaceutical of Japan, 1942, v. 63, No. 11, p. 17-19) from which only the .alpha.-form is being used in medical practice. Said polymorphous modifications can be prepared by crystallization and conversion of one form into the other.
The crystalline .gamma.-modification of para-aminobenzenesulfonamide can be prepared by dissolving in amyl alcohol of .beta.-modification followed by boiling. The resulting crystals are thermally insulated, gradually cooled to room temperature and filtered. The .gamma.-modification is identified by a radiographic analysis method.
Also known in the art is a process for preparing the .gamma.-modification of para-aminobenzenesulfonamide by pulverization of .alpha.- and .beta.-modifications and subsequently heating the resulting powder at 130.degree.-140.degree. C. for 1 hour. In this case, the .beta.-modification is converted into the .gamma.-modification. However, the .gamma.-modification of para-aminobenzenesulfonamide prepared by the processes indicted above is unstable at room temperature and is converted into the .beta.-modification which is then spontaneously converted into the .gamma.-modification. Since the resulting .gamma.-modification is unstable, its pharmacological activity has not been investigated. Said processes for preparing the .gamma.-modification of para-aminobenzenesulfonamide have not been used on an industrial scale.
DISCLOSURE
The object of the invention is to provide a process by changing the technological operations which would make it possible to obtain a physically stable crystalline .gamma.-modification of para-aminobenzenesulfonamide having high antimicrobial and interferon-inducing
The problem can be solved in that in the claimed process for preparing a physically stable crystalline .gamma.-modification of para-aminobenzenesulfonamide having, a solution of para-aminobenzenesulfonamide in water or an organic solvent or in a mixture thereof is cooled with a cooling agent at a rate of not lower than 2.degree. C./min to complete crystallization thereof followed by separation of resulting crystals and drying thereof.
It is desirable to use lower alcohols, preferably ethanol, as organic solvent. To increase the yield of the desired product, it is desirable to use liquid nitrogen or liquid carbon dioxide as the cooling agent, and to carry out the drying operation by vaccum treatment at a pressure not higher than 10.sup.-2 mm Hg. The claimed process makes it possible to obtain a physically stable crystalline .gamma.-modification of para-aminobenzenesulfonamide which is stable during storage at room temperature and has antimicrobial activity higher than the activity of the .beta.- and .alpha.-forms used in medical practice and also has a highly effective interferon-inducing activity. The claimed process is characterized by simply technology and suitable for industrial use.
BETTER EMBODIMENT OF THE INVENTION
The claimed process for preparing a physically stable crystalline .gamma.-modification of para-aminobenzenesulfonamide is carried out by cooling a solution of para-aminobenzenesulfonamide in water or an organic solvent or in a mixture thereof with a cooling agent at a rate of at least 2.degree. C./min to complete crystallization thereof followed by separation of the resulting crystals and drying thereof. The cooling agent may be any substance capable of reducing the temperature of the substance to be cooled at a rate of at least 2.degree. C./min
REFERENCES:
Lin, H. O. et al. "Polymorphism in Sulfanilamide-d4" Journal of Pharmaceutical Sciences 59(7), 972-975 (1970).
The Merck Index; Eleventh Edition; Merck & Co.:Rahway, NJ, 1989; pp. 1408-1409.
A. Watanabe and E. Kamio, J. Pharm. Soc. Japan, vol. 63, No. 11 (1942): 17-19.
Ambrose Michael G.
Richter Johann
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