The problem to be solved is to provide an important intermediate for production of an FXa inhibitor. The solution thereto is a method for industrially producing a compound (1) or a compound (4), comprising: [Step 1]: adding a quaternary ammonium salt and a metal azide salt to water to prepare an aqueous solution of an azidification reagent complex comprising quaternary ammonium salt-metal azide salt, and subsequently dehydrating the aqueous solution using an aromatic hydrocarbon solvent to form a mixed solution of the azidification reagent complex comprising quaternary ammonium salt-metal azide salt and the aromatic hydrocarbon solvent with a water content of 0.2% or less; and [Step 2]: adding, to the mixed solution prepared in [Step 1], a compound (2) wherein L represents a leaving group.

Die vorliegende Erfindung betrifft drei Varianten zur Herstellung einer Mischung aus von Milchsäure abgeleiteten cyclischen Diestern und insbesondere eines Racemates von Dilactid. Dabei kann wahlweise von den entsprechenden α-Hydroxycarbonsäuren, den entsprechenden cyclischen Diestern oder Oligomeren der entsprechenden α-Hydroxycarbonsäuren ausgegangen werden.

By reacting a β-hydroxy-α-amino acid with sulfuryl fluoride (SO₂F₂) in the presence of an organic base, it is possible to produce an α-fluoro-β-amino acid of the formula [2]. By using a C8-12 tertiary amine having two or more alkyl groups of C3 or higher, and especially diisopropylethylamine, as the organic base, by-production of quantery ammonium salts is effectively suppressed. By applying the production process of the present invention, it is possible to very easily produce

(2R)-3-(dibenzylamino)-2-fluoropropionic acid methyl ester, which is extremely important as a pharmaceutical intermediate, with high positional selectivity even on an industrial scale.

There are provided, according to the present invention, a method for producing a cis-3-substituted-3-azabicyclo[3.2.1]octan-8-ol derivative, the method characterized in that a trans-3-substituted-3-azabicyclo[3.2.1]octan-8-ol derivative or a mixture of the trans- and cis-3-substituted-3-azabicyclo[3.2.1]octan-8-ol derivatives is isomerized in the presence of an aluminum compound represented by a formula Al(OR¹)₃ (wherein R¹ represents a hydrocarbon group in which a carbon atom having an oxygen atom bonded thereto is a secondary carbon atom). In the process, a ketone compound may be further added, in addition to the aluminum compound.

Disclosed are chiral binaphthol derivatives as alanine racemase mimics having the ability to recognize amino alcohols selectively on the basis of chirality and transform amino acids from an L-form into a D-form. Methods for the optical resolution of amino acid or amino alcohol and for the optical transformation of D- and L-forms of amino acids using the binaphthol derivative are also provided.

There is provided a novel, useful dehydroxyfluorination agent containing sulfuryl fluoride (SO₂F₂) and an organic base that is free from a free hydroxyl group in the molecule. According to the present dehydroxyfluorination agent, it is not necessary to use perfluoroalkanesulfonyl fluoride, which is not preferable in large-scale use, and it is possible to advantageously produce optically-active fluoro derivatives, which are important intermediates of medicines, agricultural chemicals and optical materials, for example, 4-fluoroproline derivatives, 2'-deoxy-2'-fluorouridine derivatives, optically-active α-fluorocarboxylate derivatives, and monofluoromethyl derivatives, even in large scale.

The present invention provides three optical resolution methods. The first aspect comprises the steps of adding an optically active bifunctional resolving reagent to a bifunctional compound to form a liquid material, precipitating crystals therefrom, treating the crystals and the liquid material separately with an acidic material, a basic material, or a basic material and an acidic material, to obtain a pair of enantiomers of an optically active bifunctional compound. The second aspect comprises an optical resolution method by which one necessary enantiomer of a pair of enantiomers in an optically active bifunctional compound is exclusively obtained. The third aspect comprises a method for racemizing one unnecessary enantiomer of a pair of enantiomers in an optically active bifunctional compound which is formed by the optical resolution method of the present invention.

The present invention provides three optical resolution methods. The first aspect comprises the steps of adding an optically active bifunctional resolving reagent to a bifunctional compound to form a liquid material, precipitating crystals therefrom, treating the crystals and the liquid material separately with an acidic material, a basic material, or a basic material and an acidic material, to obtain a pair of enantiomers of an optically active bifunctional compound. The second aspect comprises an optical resolution method by which one necessary enantiomer of a pair of enantiomers in an optically active bifunctional compound is exclusively obtained. The third aspect comprises a method for racemizing one unnecessary enantiomer of a pair of enantiomers in an optically active bifunctional compound which is formed by the optical resolution method of the present invention.

Process for the racemization of an optically active amino acid amide by reacting the amino acid amide with a carboxylic acid in the presence of a solvent, of water and of 0.5-4 equivalents of an aldehyde, calculated relative to the quantity of amino acid amide. Instead of an amino acid amide, the Schiff base of an amino acid amide and an aldehyde can also be used, in which case no extra aldehyde has to be added and the required quantity of water amounts to at least 1 equivalent relative to the quantity of Schiff base. This process gives fast racemization and a high yield of salt of the racemized amino acid amide and the carboxylic acid.

A process for the racemization of optically active 4-phenylbutanoic acid esters which comprises treating optically active 4-phenylbutanoic acid esters of the general formula (I) wherein R¹ represents a hydroxy group, a hydroxy group protected by a vinyl ether, or a lower acyloxy group and R² repesents a lower alkyl group with a base selected from the group consisting of alkali metal alcoholates, alkali metal hydrides, and alkali metal amides is provided.