2-acylaminothiazole derivative or salt thereof

Abstract

A 2-acylaminothiazole derivative or a pharmaceutically acceptable salt thereof having an excellent effect of proliferating human c-mpl-Ba / F3 cells and an activity of increasing platelets based on the effect of promoting the formation of megakaryocytic colonies. A compound or a pharmaceutically acceptable salt thereof useful in treating thrombocytopenia.

Description

TECHNICAL FIELD[0001]The present invention relates to a novel 2-acylaminothiazole derivative or a salt thereof, which is useful as a medicament particularly in the treatment of thrombocytopenia, and pharmaceutical composition comprising the compound as an active ingredient.BACKGROUND ART[0002]A platelet is a nuclear blood cell playing an important role in physiological hemostasis and pathological thrombosis, and is continuously produced from megakaryocytes in a living organism. The platelet originates from pluripotent stem cells like other blood cells. Specifically, the pluripotent stem cell becomes a megakaryocytic progenitor cell, from which megakaryoblasts, promegakaryocytes, and megakaryocytes are formed. During the maturation of a megakaryocyte, premature megakaryocytes only carry out DNA synthesis without involving cell division to become a polyploid. Thereafter, cytoplasm begins to mature to form a platelet separation membrane, and a platelet is released by cytoplasm fragment...

AI Technical Summary

Benefits of technology

[0027]The present inventors, as a result of assiduous studies on compounds having platelet increasing activity, discovered that novel 2-acylaminothiazole derivatives have excellent effect of increasing the number of platelets, and completed the present invention.

[0139]The compound of the present invention is a 2-acylaminothiazole derivative structurally characterized in that an acylamino group is substituted at the 2-position thereof and that a nitrogen atom of a nitrogen-containing heterocycle is directly bound to the 5-position thereof. Also, it has pharmacological characteristics of showing the effects of proliferating human c-mpl Ba / F3 cells and promoting differentiation of human CD34+ into megakaryocytes, and good effects in oral administration test for mice, and thus, having the activity of increasing the number of platelets.

[0193]Particularly, it is advantageous to carry out the reaction in a solvent such as acetonitrile or DMF using a base such as pyridine or N,N-dimethylaniline, or using pyridine as a solvent.

[0197]In case a hydrogen halide is used as a halogenation agent, the compound (1a) can be reacted therewith in an acid solution or a base solution such as sodium hydroxide aqueous solution, and the reaction is preferably carried out at −30° C. to reflux temperature of the used solvent. And, in case a metal agent is used as a halogenation agent, the compound (1a) is generally dissolved in an inert organic solvent such as halogenated hydrocarbon, ether, alcohol, aromatic hydrocarbon, acetic acid, ester, and the like, or water, or a mixture thereof to react with the agent, and if necessary, it is advantageous to carry out the reaction in the presence of a small amount of a catalyst such as hydrogen halide, under room temperature to heating.

[0206]The compound and its salt of the present invention have excellent effects of increasing the number of platelets. Thus, the compound of the present invention is useful in the treatment and / or prevention of thrombocytopenia due to aplastic anemia, myelodysplastic syndrome, chemotherapy or radiotherapy for malignant tumors, idiopathic thrombocytopenic purpura, liver disease, HIV, and the like. In case thrombocytopenia is likely to be caused by chemotherapy or radiotherapy, it is possible to administrate the compound of the present invention prior to carrying out the therapy.

[0218]From the above results, it has been verified that the compound of the present invention has oral activity in mice. Particularly, it is very surprising that the control did not show oral activity at 100 mg / kg, while the compound of the present invention showed good oral activity even at 10 mg / kg, which is considered to be achieved by the introduction of a directly bonding nitrogen atom at the 5-position of thiazole. And, controls 2 and 3 showed <10% of cell proliferation activity with the same dose (10 mg / kg p.o.) as the compounds of Examples. It has also been confirmed that, in a mouse in which human platelet production is recognized after transplanting human hematopoietic stem cells, effects of increasing the number of platelets are recognized by orally administering the compound of the present invention.

Problems solved by technology

At present, although platelet transfusion is a powerful means for treating thrombocytopenia, a sufficient amount of platelets cannot be provided, and it is difficult to sufficiently improve thrombocytepenia because of a short life span of transfused platelets and the like.

Additionally, platelet transfusions involve problems including viral infection, production of alloantibodies, Graft Versus Host Disease (GVHD), and the like.

And, because TPO is a protein, it is decomposed in the digestive tract, and thus is not practical as an agent for oral administration.

For the same reason, it is considered that a low molecular peptide is also not practical as an agent for oral administration.

Also, the above publication does not disclose concretely in the Examples and the other parts a compound wherein the 5-position of thiazole is directly substituted with a nitrogen atom.

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