Abstract: An N-9-position alkylated form is selectively precipitated by subjecting a mixture containing the N-9-position alkylated form and an N-7-position alkylated form of 2-amino-6-halopurine to a crystallization step using a mixed solvent of an organic solvent and water. Then, this N-9-position alkylated form is reduced to give famciclovir. By this method of the present invention, famciclovir known as an antiviral agent, and an intermediate compound therefor can be efficiently produced.

Abstract: Herein is disclosed a process for producing an &agr;-aminohalomethyl ketone derivative which comprises subjecting to catalytic reduction the corresponding &agr;-aminodihalomethyl ketone derivative, and which process is efficient and suited for industrial production 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: An amino group of an &agr;-amino acid ester is protected as an imine, and it is then reacted with a halomethyllithium to obtain an N-protected-&agr;-aminohalomethylketone. Further, this N-protected-&agr;-aminohalomethylketone is treated with an acid to obtain an &agr;-aminohalomethylketone. This process is suited for industrial production, and can produce an &agr;-aminohalomethylketone and its related compounds economically and efficiently.

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: The present invention provides a method for efficiently producing &bgr;-D-ribofuranose derivatives or optical isomers thereof, useful as synthetic intermediates of pharmaceutical nucleic acid-series products. The method comprises a step of producing 1-O-benzyl-&bgr;-D-ribofuranose-2,3,5-triacetate or an optical isomer thereof by allowing &bgr;-D-ribofuranose-1,2,3,5-tetraacetate or an optical isomer thereof to react with a benzyl alcohol in the presence of acid catalysts and a step of hydrolyzing the resulting 1-O-benzyl-&bgr;-D-ribofuranose-2,3,5-triacetate in the presence of a base to produce 1-O-benzyl-&bgr;-D-ribofuranose or an optical isomer thereof.

Abstract: The present invention provides methods for producing a highly pure aromatic bromocarboxylic acid derivative and an aromatic acylthiocarboxylic acid derivative in high yields. The methods of the present invention include reacting an aromatic amino acid in an aqueous solvent in the presence of sodium nitrite, hydrogen bromide and at least one member selected from the group consisting of an aliphatic carboxylic acid and an alcohol, to give an aromatic bromocarboxylic acid derivative, and reacting the aromatic bromocarboxylic acid derivative and an organic thio acid in the presence of an amine to give an aromatic acylthiocarboxylic acid derivative.

Abstract: The present invention provides a production method including adding water to a solution of (2R,3S)-3-tert-butoxycarbonylamino-1,2-epoxy-4-phenylbutane ((2R,3S)-epoxide compound) or (2S,3R)-3-tert-butoxycarbonylamino-1,2-epoxy-4-phenylbutane ((2S,3R)-epoxide compound) in a polar solvent to allow crystallization, whereby to produce crystals of the (2R,3S)-epoxide compound or the (2S,3R)-epoxide compound conveniently in a high yield by an industrial production method without requiring an extremely low temperature.

Abstract: The invention relates to a method for industrially producing highly pure (2R, 3S)- or (2S, 3R)-N-carbamate-protected &bgr;-aminoepoxide (crystal) or (2R, 3S)- or (2S, 3R)-N-carbamate-protected &bgr;-aminoalcohol.

Abstract: There can be provided an excellent industrial process for producing compounds having sugar-moiety hydroxyl groups or halogen atoms reduced in nucleic acids or in derivatives thereof by allowing O-thiocarbonyl derivatives of sugar-moiety hydroxyl groups or allowing halogenated derivatives in the sugar-moiety, in the nucleic acids or in derivatives thereof to react with any one of hypophosphorous acids (including salts thereof) and phosphites (esters) which are inexpensive, non-toxic and safely usable as radical reducing agents in industrial scale, in the presence of a radical reaction initiator.

Abstract: The present invention provides a method for industrially producing an optically active lysine derivative useful as a pharmaceutical intermediate. More particularly, the present invention provides a production method including protecting an amino group or an amino group and carboxyl group of optically active 2-amino-6-methyl-6-nitroheptanoic acid with a protecting group, reducing a nitro group to synthesize a 6,6-dimethyl lysine derivative and reacting the 6,6-dimethyl lysine derivative with an acetic acid derivative.

Abstract: Herein is disclosed a process for producing an &agr;-aminohalomethyl ketone derivative which comprises subjecting to catalytic reduction the corresponding &agr;-aminodihalomethyl ketone derivative, and which process is efficient and suited for industrial production thereof.

Abstract: A process for producing &agr;-aminohalomethyl ketones or N-protected &agr;-aminohalomethyl ketones from specified 3-oxazolidin-5-one derivatives via 5-halomethyl-5-hydroxy-3-oxazolidine derivatives. By this process, &agr;-aminohalomethyl ketones and compounds relating to them can be obtained efficiently and economically in industrial scale.

Abstract: A process for producing &agr;-amino-dihalogenated methyl ketone derivatives by reacting an N-protected &agr;-amino acid ester with a dihalomethyl lithium is provided. This process is suitable for the production on an industrial scale and by this process, &agr;-amino-dihalogenated methyl ketone derivatives and &bgr;-amino-&agr;-hydroxycarboxylic acid derivatives can be obtained efficiently and economically advantageously.

Abstract: An amino group of an &agr;-amino acid ester is protected as an imine, and it is then reacted with a halomethyllithium to obtain an N-protected-&agr;-aminohalomethylketone. Further, this N-protected-&agr;-aminohalomethylketone is treated with an acid to obtain an &agr;-aminohalomethylketone. This process is suited for industrial production, and can produce an &agr;-aminohalomethylketone and its related compounds economically and efficiently.

Abstract: The present invention provides methods for producing a highly pure aromatic bromocarboxylic acid derivative and an aromatic acylthiocarboxylic acid derivative in high yields. The methods of the present invention include reacting an aromatic amino acid in an aqueous solvent in the presence of sodium nitrite, hydrogen bromide and at least one member selected from the group consisting of an aliphatic carboxylic acid and an alcohol, to give an aromatic bromocarboxylic acid derivative, and reacting the aromatic bromocarboxylic acid derivative and an organic thio acid in the presence of an amine to give an aromatic acylthiocarboxylic acid derivative.

Abstract: Optically active N-(S-2-acetylthiomethyl-1-oxo-3-phenylpropyl)-glycine benzyl ester useful as an enkephalin inhibitory agent or ACE inhibitory agent can be produced at low cost in an industrial manner, by a method comprising subjecting optically active 2-hydroxymethyl-3-phenylpropionic acid and glycine benzyl ester to condensation to subsequently convert the hydroxyl group into an elimination group, and substituting the elimination group with an acetylthio group.

Abstract: A process for producing optically active amino acid derivatives having a cyclohexyl group or a substituted cyclohexyl group by hydrogenating an amino acid derivative containing an aromatic group in the presence of a ruthenium catalyst. The starting material may be an unprotected amino acid or an N- and/or C-protected derivative thereof. An major advantage of the process is that the reduction may be accomplished without substantial racemization.

Abstract: Optically active N-(S-2-acetylthiomethyl-1-oxo-3-phenylpropyl)-glycine benzyl ester useful as an enkephalin inhibitory agent or ACE inhibitory agent can be produced at low cost in an industrial manner, by a method comprising subjecting optically active 2-hydroxymethyl-3-phenylpropionic acid and glycine benzyl ester to condensation to subsequently convert the hydroxyl group into an elimination group, and substituting the elimination group with an acetylthio group.

Abstract: Provided is an industrially useful process for producing an optically active 2-hydroxy-4-arylbutyric acid or its ester. An optically active acyloxysuccinic anhydride is reacted with an aromatic compound in the presence of a Lewis acid to produce an optically active 2-acyloxy-4-oxo-4-arylbutyric acid. The 2-acyloxy-4-oxo-4-arylbutyric acid is converted to an optically active 2-acyloxy-4-arylbutyric acid through catalytic reduction. The 2-acyloxy-4-arylbutyric acid is hydrolyzed in the presence of an acid or an alkali to produce an optically active 2-hydroxy-4-arylbutyric acid. The 2-hydroxy-4-arylbutyric acid is reacted with an alcohol in the presence of an acid to produce an optically active 2-hydroxy-4-arylbutyric acid ester.