Abstract: Provided is a compound having at least one selected from the group consisting of cell growth promoting activity, angiogenesis promoting activity, lumen formation promoting activity, cell migration promoting activity, and neurocyte growth promoting activity, which is a chemically stable low-molecular-weight substance that has high absorbability and can be supplied stably at a low cost because of its low molecular weight. A cyclobutyl purine derivative, a tautomer or stereoisomer thereof, or a salt, solvate, or hydrate thereof according to the present invention is a cyclobutyl purine derivative represented by the following general formula (1), a tautomer or stereoisomer thereof, or a salt, solvate, or hydrate thereof.

Abstract: Provided is a compound having at least one selected from the group consisting of cell growth promoting activity, angiogenesis promoting activity, lumen formation promoting activity, cell migration promoting activity, and neurocyte growth promoting activity, which is a chemically stable low-molecular-weight substance that has high absorbability and can be supplied stably at a low cost because of its low molecular weight. A cyclobutyl purine derivative, a tautomer or stereoisomer thereof, or a salt, solvate, or hydrate thereof according to the present invention is a cyclobutyl purine derivative represented by the following general formula (1), a tautomer or stereoisomer thereof, or a salt, solvate, or hydrate thereof.

Abstract: Novel intermediates of nucleoside derivatives, of which the 6-position of the nucleic acid base moiety is substituted with a halogen atom, are produced. Using those novel intermediates, even substrates, of which the 3′-position of the saccharide moiety is deoxylated, can be substituted at the 2′-position at an extremely high yield. Specifically, by subjecting a 3′-deoxy derivative of inosine to 6-halogenation to give a 6-halide of the derivative, and then subjecting it to 2′-deoxylation/substitution with a fluorine atom or the like, followed by further subjecting it to substitution with an amino group, a hydroxyl group or any other intended substituent at the 6-positioned halogen atom, nucleoside derivatives are produced at a high yield.

Abstract: Novel intermediates of nucleoside derivatives, of which the 6-position of the nucleic acid base moiety is substituted with a halogen atom, are produced. Using those novel intermediates, even substrates, of which the 3′-position of the saccharide moiety is deoxylated, can be substituted at the 2′-position at an extremely high yield. Specifically, by subjecting a 3′-deoxy derivative of inosine to 6-halogenation to give a 6-halide of the derivative, and then subjecting it to 2′-deoxylation/substitution with a fluorine atom or the like, followed by further subjecting it to substitution with an amino group, a hydroxyl group or any other intended substituent at the 6-positioned halogen atom, nucleoside derivatives are produced at a high yield.

Abstract: Novel intermediates of nucleoside derivatives, of which the 6-position of the nucleic acid base moiety is substituted with a halogen atom, are produced. Using those novel intermediates, even substrates, of which the 3′-position of the saccharide moiety is deoxylated, can be substituted at the 2′-position at an extremely high yield. Specifically, by subjecting a 3′-deoxy derivative of inosine to 6-halogenation to give a 6-halide of the derivative, and then subjecting it to 2′-deoxylation/substitution with a fluorine atom or the like, followed by further subjecting it to substitution with an amino group, a hydroxyl group or any other intended substituent at the 6-positioned halogen atom, nucleoside derivatives are produced at a high yield.

Abstract: Novel intermediates of nucleoside derivatives, of which the 6-position of the nucleic acid base moiety is substituted with a halogen atom, are produced. Using those novel intermediates, even substrates, of which the 3'-position of the saccharide moiety is deoxylated, can be substituted at the 2'-position at an extremely high yield. Specifically, by subjecting a 3'-deoxy derivative of inosine to 6-halogenation to give a 6-halide of the derivative, and then subjecting it to 2'-deoxylation/substitution with a fluorine atom or the like, followed by further subjecting it to substitution with an amino group, a hydroxyl group or any other intended substituent at the 6-positioned halogen atom, nucleoside derivatives are produced at a high yield.Methods for producing nucleoside derivatives including 9-(2,3-dideoxy-2-fluoro-.beta.