Abstract: Compounds formed by reacting a protected amino acid with an alkali metal enolate of an alkyl acetate are reacted with a halogenating agent for halogenation of the 2-position, or a protected amino acid is reacted with an alkali metal enolate of an alkyl halogenoacetate, to form a 4-amino-3-oxo-2-halogenobutanoic acid ester derivative, and hydrolysis and decarboxylation are conducted to produce a 3-amino-2-oxo-1-halogenopropane derivative or its salt. The present method is a useful process for producing a 3-amino-2-oxo-1-halogenopropane derivatives which can easily be converted to a 3-amino-1,2-epoxypropane.

Abstract: The present invention provides a simple and inexpensive method for producing .alpha.-hydroxy-.beta.-aminocarboxylic acids and their esters. An ester of an N-protected .alpha.-amino acid ester is converted into a .beta.-ketosulfoxide, which is then processed with an acid to give an .alpha.-ketohemimercaptal. Next, this is acylated and then processed with a base to obtain an N-protected .alpha.-acyloxy-.beta.-amino-thioester, which is then saponified to obtain an intended compound. According to the method of the present invention, it is possible to produce .alpha.-hydroxy-.beta.-aminocarboxylic acid derivatives, which are intermediates in producing various HIV protease inhibitors, renin inhibitors and carcinostatics, from a-amino acids. The method comprises reduced reaction steps, the selectivity in the method to give the intended product is high, and the yield of the product obtained is high.

Abstract: Herein is disclosed a novel and industrially advantageous process for synthesizing acyclic nucleosides such as acyclovir and ganciclovir from ribonucleosides, which process comprises adding an acid catalyst and an acid anhydride to a solution of a ribonucleoside such as guanosine and an ester derivative of an acyclic sugar, and heating the mixture, whereby a transglycosilation reaction takes place between the ribose moiety of the ribonucleoside and the ester derivative of the acyclic sugar.Herein is also disclosed an industrially favorable method for the separation of 9-substituted purine nucleosides which are important intermediates for the synthesis of acyclic nucleosides such as acyclovir, ganciclovir, and the like from ribonucleosides, which method comprises crystallizing only the 9-isomer from a solution or suspension containing both a 9-substituted purine nucleoside and a 7-substituted purine nucleoside by cooling the solution or/and by adding a crystallizing solvent thereto.

Abstract: Nucleoside derivatives such as 2'-deoxy-2'-bromo-5'-O-acetyl-5-methyluridine, etc., are important intermediates which can be converted into nucleoside derivatives, such as 3'-azido-3'-deoxythymidine, etc., which are useful as medicines.

Abstract: A process for preparing a 2', 3'-dideoxy-2',3'-didehydropyrimidine nucleoside comprising reacting the pyrimidine ribofuranoside with a trialkyl orthoester to yield the 2',3'-O-alkoxyethylidene derivative; which is reacted with hydrogen bromide in acetic acid or acetyl bromide to yield the 2-deoxy-2'-bromo-3'-acetyl-pyrimidine nucleoside; which is then reduced with zinc to yield the 2',3'-olefin of the pyrimidine nucleoside.

Abstract: 5-Cyclohexylmethylhydantoin derivatives may be conveniently prepared by reducing, in the presence of a metal catalyst, a 5-(3-cyclohexene-1-yl)melthylenehydantoin derivative which is obtained by the condensation of a hydantoin derivative and a 3-cyclohexene-1-carbaldehyde derivative in the presence of a monoalkanolamine.

Abstract: A crude 2',3'-dideoxynucleoside compound is purified by extracting with an organic solvent, or crystallizing, the 2',3'-dideoxynucleoside compound from a basic aqueous solution having a pH of not less than 12 containing the same. In another embodiment of purification a basic aqueous solution having a pH of not less than 11 of a crude 2',3'-dideoxynucleoside derivative is brought into contact with a nonpolar porous resin, whereby the derivative is adsorbed on the resin, and then the thus adsorbed derivative is desorbed with an aqueous alcoholic solution.2',3'-Dideoxynucleoside compounds which have utility as anti-AIDS drugs or anti-virus drugs can be isolated and purified in high purity and in high yield from their crude products containing impurities.

Abstract: Optically active pyrrolidine derivative represented by the following formula (XI): ##STR1## wherein R.sup.1 represents a benzyl group R.sup.2 represents an alkyl group having 1 to 6 carbon atoms, R.sup.3 represents an alkyl group having 1 to 6 carbon atoms, a benzyl group or an allyl group, R.sup.4 is selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may be substituted with a protected hydroxyl group, a vinyl group, a phenyl group which may be substituted, a benzyl group which may be substituted, and a heterocyclic ring having 1 to 4 nitrogen or/and oxygen atoms, and R.sup.5 represents a hydrogen atom or a methyl group.This compound can be an intermediate for synthesis of carbapenem antibiotic compounds.

Abstract: Herein is disclosed a novel and industrially advantageous process for synthesizing acyclic nucleosides such as acyclovir and ganciclovir from ribonucleosides, which process comprises adding an acid catalyst and an acid anhydride to a solution of a ribonucleoside such as guanosine and an ester derivative of an acyclic sugar, and heating the mixture, whereby a transglycosilation reaction takes place between the ribose moiety of the ribonucleoside and the ester derivative of the acyclic sugar.

Abstract: Herein is disclosed a process for producing a .beta.-ketoalcohol by the oxidative ring-opening reaction of a 1,3-dioxane derivative, said .beta.-ketoalcohol being able to be a substrate for asymmetric reaction.

Abstract: Platinum complexes of cis-diaminocyclohexanol or cis-diaminocyclohexane, with the exclusion of platinum complexes of 2-deoxystreptamine, having high anti-tumor activity, low toxicity, water-solubility and exhibiting no cross-resistance to cis-platin.

Abstract: A process for producing L-serine by the combination of chemical synthesis and enzyme chemical synthesis is disclosed. In this process L-serine is biochemically produced from 2-oxo-axazolidine-4-carboxylic acid or a salt thereof.