Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-11-13
2003-06-17
Aulakh, Charanjit S. (Department: 1616)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C546S021000, C540S363000, C540S528000
Reexamination Certificate
active
06579989
ABSTRACT:
This application is a 371 of PCT/JP00/03055 filed May 12, 2000, now WO 00/69868 published Nov. 23, 2000.
TECHNICAL FIELD
The present invention relates to physiologically active substances, sulphostin and a sulphostin analogue and a process for producing the same. The compounds in accordance with the present invention possess a dipeptidylpeptidase IV inhibiting activity and are expected to be a physiologically active substance to be used, for example, as immunomodulating agents, hormone-modulating agents, anti-HIV drugs, antiallergic drugs, anti-inflammatory drugs and antirheumatic drugs.
BACKGROUND ART
Dipeptidylpeptidase IV present on the surface of T cells is known to concern itself with the activation of T cells (Immunol. Today, 15, 180-184(1994)) and is playing an important role in an immune system. In addition, the dipeptidylpeptidase IV concerns itself with the decomposition of growth-hormone-releasing hormone (J. Clin. Invest., 83, 1533-1540(1989)).
Previously, diprotin A and B and the like are known as the physiologically active substances possessing a dipeptidylpeptidase IV inhibiting activity (J. Antibiotics, 37, 422-425(1984)).
However, it cannot be said that the inhibiting activity of diprotin A and B against enzymes is sufficiently high. Therefore, a physiologically active substance possessing a higher inhibiting activity has been desired.
The present inventors previously found sulphostin as such a physiologically active substance, and developed a process for producing the same in a manner such that microorganisms which belong to Sttreptomyces and are capable of producing sulphostin of a physiologically active substance, are cultured in a medium, and the physiologically active substance, sulphostin, produced and accumulated in the cultivated substance is collected (Japanese Patent Application No. 9-317221). However, the sulphostin can exhibit a strong inhibiting activity against enzymes, yet the process of collecting it from the cultivated substance of microorganisms is not always said to be high in productivity, and the process is not suitable for mass production.
DISCLOSURE OF INVENTION
The present inventors have satisfactorily clarified a chemical structure of the physiologically active substance, sulphostin, and found that it can be obtained according to a synthetic chemical means. Further, it has been found that stereo isomers and analogues of the sulphostin, which are not naturally occurring, can be obtained similarly according to a synthetic chemical means, and can exhibit a strong enzyme inhibiting activity like the sulphostin. The present invention has been accomplished on the basis of the above-mentioned knowledge.
The present invention provides a sulphostin analogue represented by a general formula (IV′) or a pharmaceutically acceptable salt thereof,
wherein n is an integer of from 0 to 3, provided that a case where n is 2 and steric configurations of C* and P* are S and R, respectively, is excluded.
Further, the present invention provides a process for producing sulphostin or a sulphostin analogue represented by a general formula (IV),
wherein n is an integer of from 0 to 3, which comprises allowing a compound represented by a general formula (II),
wherein n is as defined above, and Z is an amino group-protecting group, to reaction with sulfur trioxide or a complex thereof, if necessary followed by cation exchange, thereby obtaining a compound represented by a general formula (III),
wherein n and Z are as defined above, and M is a monovalent cation, and then removing the protecting group.
Still further, the present invention provides a process for producing a compound represented by a general formula (II),
wherein n is an integer of from 0 to 3, and Z is an amino group-protecting group, which comprises allowing a compound represented by a general formula (I),
wherein n and Z are as defined above, to react with a base, followed by reaction with phosphorus oxychloride or POX
3
in which X is a halogen or imidazole, and further followed by reaction with ammonia in order.
BEST MODE FOR CARRYING OUT THE INVENTION
The present inventors have clarified that according to a variety of spectrography, the sulphostin has a chemical structure represented by the following formula (V). In addition, on the basis of a fact that L-ornithine is obtained through an experiment comprising a hydrolysis thereof, it has been also clarified that a steric configuration at a joint of the amino group is S.
According to such a knowledge, the sulphostin has been synthesized in a manner mentioned below.
L-Ornithine is esterified, followed by ring-closure, thereby obtaining L-ornithine lactam, whose amino group is then protected in a conventional manner to obtain a compound of a general formula (VI).
In the formula, Z is a conventional amino group-protecting group, for example, carbamate type protecting groups such as a benzyloxycarbonyl group, whose benzyl group may be substituted with those such as a lower alkyl group, a lower alkoxy group, an acyloxy group, a nitro group and a halogen, and t-butoxycarbonyl group, amide type protecting groups such as formyl, acetyl and trifluoroacetyl, and imide type protecting groups such as phthaloyl. Preferred are carbamate type protecting groups, and more preferred is a benzyloxycarbonyl group.
Successively, the compound of the formula (VI) is treated in a non-aqueous solvent with a base, followed by reaction with POX
3
in which X is an eliminating group such as a halogen and imidazole, preferably a halogen, and further followed by reaction with ammonia, thereby obtaining a compound of a general formula (VII).
In the formula, Z is the same amino group-protecting group as in the general formula (VI). The solvent includes an aprotic solvent, and may be anything capable of dissolving the compound of the formula (VI). Preferred is an ether solvent such as THF. The base may be anything capable of substituting hydrogen of the lactam with a metal, and includes butyllithium, sodium hydride, lithium hydride, potassium hydride, sodium bistrimethylsilylamide and lithium bistrimethylsilylamide. Preferred is butyllithium. The reaction can be carried out at a temperature of from −80 to 100° C., preferably from −80 to 0° C.
Successively, the compound of the formula (VII) is allowed to react with sulfur trioxide or a complex thereof such as a pyridine complex, a DMF complex and a trimethylamine complex, at a temperature of from 0 to 100° C., preferably from 0 to 10° C., if desired followed by cation exchange, thereby obtaining a compound of a general formula (VIII).
In the formula, Z is the same amino group-protecting group as in the general formula (VI), and M
+
is a monovalent cation such as Li
+
, Na
+
, K
+
, R
3
NH
+
, R
2
NH
2
+
, RNH
3
+
and pyridinium, in which R is a lower alkyl group substituted or unsubstituted with an aryl group such as phenyl and naphthyl. The solvent includes an aprotic solvent such as 1,2-dichloroethane, chloroform, methylene chloride, tetrahydrofuran, dioxane, DMF, dimethylacetamide, hexamethylphosphoramide (HMPA), N-methylpyrrolidone and acetonitrile. Preferred is dimethylformamide (DMF). The compound of the general formula (VIII) is a mixture of two diastereoisomers in relation to the asymmetric carbon at a joint of the protected amino group, because asymmetry is newly generated at the phosphorus atom. These isomers can be separated from each other in a manner such that an aqueous solution of sodium hydroxide, sodium carbonate, sodium hydrogen carbonate or the like is added to the above-mentioned reaction mixture to perform neutralization, thereby obtaining a sodium salt thereof, or an aqueous solution of potassium hydroxide, potassium carbonate, potassium hydrogen carbonate or the like is added to the above-mentioned reaction mixture to perform neutralization, thereby obtaining a potassium salt thereof, which salt is then subjected to chromatography. In the chromatography, SEPHADEX LH 20, anion exchange resins, polystyrene based adsorption resins (DIAION HP 20,
Abe Masatoshi
Akiyama Tetsuo
Harada Shigeko
Muraoka Yasuhiko
Takeuchi Tomio
Aulakh Charanjit S.
Nields & Lemack
Zaidan Hojin Biseibutsu Kagaku Kenkyu Kai
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