Showing papers by "Kunisuke Izawa published in 2002"
TL;DR: The title compound is obtained in high yield after decarboxylation of the alpha-halo-beta-ketoester, which is prepared by cross-Claisen condensation using N-protected amino acid ester.
25 citations
TL;DR: Perfluoroalkanesulfonyl fluorides are effective dehydroxy-fluorination agents for the hydroxyl group at the sugar moiety of nucleoside derivatives and give the corresponding fluorinated nucleosides in good yield with an inversion of configuration in a single step.
Abstract: Perfluoroalkanesulfonyl fluorides are effective dehydroxy-fluorination agents for the hydroxyl group at the sugar moiety of nucleoside derivatives and give the corresponding fluorinated nucleosides in good yield with an inversion of configuration in a single step.
23 citations
Patent•
30 Aug 2002
TL;DR: In this paper, an N-9 position alkylated form of 2-amino-6-halopurine was selectively precipitated by subjecting a mixture of a mixture containing the n-9position alkylation form and an n-7position alization form to a crystallization step using a mixed solvent of an organic solvent and water.
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.
5 citations
TL;DR: In this paper, Hypophosphorous acid and dialkyl phosphites are used to reduce O-thiocarbonyl groups or halides at the sugar part of nucleoside derivatives and give the corresponding hydrocarbons in high yield.
Abstract: Hypophosphorous acid and dialkyl phosphites are effective radical reducing agents for O-thiocarbonyl groups or halides at the sugar part of nucleoside derivatives and give the corresponding hydrocarbons in high yield.
2 citations
Patent•
29 Oct 2002TL;DR: In this paper, a method for industrial production of optically active lysine derivatives useful as a pharmaceutical intermediate is presented, which includes protecting an amino group or amino group and carboxyl group of 2-amino, 6-methyl-6-nitroheptanoic acid with a protecting group.
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.
1 citations
Patent•
10 Oct 2002TL;DR: In this article, a process for α-aminohalomethyl ketones and compounds relating to them can be obtained efficiently and economically in industrial scale using 3-oxazolidin-5-one derivatives.
Abstract: A process for producing α-aminohalomethyl ketones or N-protected α-aminohalomethyl ketones from specified 3-oxazolidin-5-one derivatives via 5-halomethyl-5-hydroxy-3-oxazolidine derivatives. By this process, α-aminohalomethyl ketones and compounds relating to them can be obtained efficiently and economically in industrial scale.