Provided is a method for producing a 2-alkylcarbonylnaphtho[2,3-b]furan-4,9-dione-related substance, which is suitable for the production on an industrial scale. The present invention provides: a method for producing an intermediate for the production of a 2-alkylcarbonyl[2,3-b]furan-4,9-dione, which comprises reacting a 1-butyne derivative in which a ketone or an alcohol is protected with a 2-hydroxy-1,4-naphthoquinone derivative having a leaving group at position-3 in a solvent in the presence of a metal or a metal compound and a base; and a substance relating to the intermediate.

The present invention discloses an organic compound represented by the following formula (1) and an organic electroluminescence device using the organic compound as the phosphorescent host material, the fluorescent host material, or the fluorescent dopant material. The organic compound may lower a driving voltage or power consumption, or may increase a current efficiency or half-life of the organic electroluminescence device.

##STR00001##

The same definition as described in the present invention.

The present invention discloses an organic compound represented by the following formula (1) and an organic electroluminescence device using the organic compound as the phosphorescent host material, the fluorescent host material, or the fluorescent dopant material. The organic compound may lower a driving voltage or power consumption, or may increase a current efficiency or half-life of the organic electroluminescence device.

##STR00001##

The same definition as described in the present invention.

The present invention addresses the problem of providing a novel chemically activated water-soluble prodrug. The present invention provides a compound represented by formula (1), or a pharmacologically acceptable salt thereof (in the formula, A represents A-0; X.sup.1 and X.sup.2 are the same as or different from each other and each independently represent a hydroxyl group or OC(O)Y(C(R.sup.1A) (R.sup.1B))n-NHR.sup.2, where X.sup.1 and X.sup.2 are not simultaneously hydroxyl groups, n is 2, 3, or 4, Y represents an oxygen atom or NR.sup.4, R.sup.1A and R.sup.1B are the same as or different from each other and each independently represent a hydrogen atom, etc., and R.sup.2 represents a hydrogen atom, etc.; and R.sup.a to R.sup.d are optionally present, are the same as or different from each other, and each independently represent a hydrogen atom, etc.).

Disclosed are a tetrahydronaphtho[1,2-b]furan-2(3H)-one derivative of formula (I) and a method of making the same, where definitions of R, R.sub.1 and R.sub.2 herein are the same as those in the specification. It has been demonstrated by animal experiments that the tetrahydronaphtho[1,2-b]furan-2(3H)-one derivative can significantly inhibit the adjuvant-induced in Wistar male rats so that it can alleviate the primary and secondary lesions, showing a preventive activity to some extent. Therefore, the tetrahydronaphtho[1,2-b]furan-2(3H)-one derivative provided herein is applicable to the preparation of a drug for preventing/treating rheumatoid arthritis, and has promising clinical applications.

##STR00001##

The problem of the present invention is to provide a useful prodrug compound of a naphthofuran compound. The present invention relates to a compound represented by the formula (IA): ##STR00001##
[wherein each symbol is as described in the DESCRIPTION] or a pharmaceutically acceptable salt thereof.

The problem of the present invention is to provide a useful prodrug compound of a naphthofuran compound. The present invention relates to a compound represented by the formula (IA): ##STR00001##
[wherein each symbol is as described in the DESCRIPTION] or a pharmaceutically acceptable salt thereof.

The invention addresses the problem of providing a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione that is suited to industrial production. The invention provides a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by reacting 3-bromo-3-buten-2-one and 2-hydroxy-1,4-naphthoquinone in the presence of a solvent, then obtaining crystals of 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by adding an alcohol-based solvent and/or water to the reaction system, and treating the crystals by using a specific adsorbent in the presence of a solvent.

The invention addresses the problem of providing a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione that is suited to industrial production. The invention provides a method for producing 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by reacting 3-bromo-3-buten-2-one and 2-hydroxy-1,4-naphthoquinone in the presence of a solvent, then obtaining crystals of 2-acetyl-4H,9H-naphtho[2,3-b]furan-4,9-dione by adding an alcohol-based solvent and/or water to the reaction system, and treating the crystals by using a specific adsorbent in the presence of a solvent.

The present invention provides a compound of the following Formula (1) or a pharmaceutically acceptable salt thereof: ##STR00001##
wherein X is an oxygen atom and the like; Y is CO, SO.sub.2 and the like; R.sup.1 is an optionally-substituted C.sub.1-6 alkyl group, an optionally-substituted C.sub.1-6 alkylcarbonyl group and the like; R.sup.2 is an optionally-substituted C.sub.1-6 alkyl group, an optionally-substituted C.sub.1-6 alkoxy group, an optionally-substituted amino group, an optionally-substituted 5- to 12-membered monocyclic or polycyclic saturated heterocyclic group and the like; R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are independently a hydrogen atom and the like which exhibits excellent effects in suppressing the proliferation and sphere-forming ability of cancer cells, and can be useful as an antitumor drug or cell growth inhibitor.