Takasago International Corporation

Daiichi Pharmaceutical Co., Ltd.

Yoshiki Okeda

Toshimitsu Hagiwara

Yoji Hori

Hidenori Kumobayashi

Shinya Yamada

Akio Tachikawa

Noboru Sayo

Takao Saito

Hidemasa Takaya

Yoshifumi Yuasa

Tsutomu Hashimoto

Nobuo Seido

Haruki Tsuruta

Tetsuo Ohta

Yoshiharu Gonda

Takeshi Iwata

Toshihiro Fujiwara

Shunichi Harada

Hiroyuki Nagashima

Hidonori Kumobayashi

Kouji Ishiguro

Akira Nagakura

Process for producing isopulegol

A process for producing a pivaloylacetic acid ester comprises reacting pivaloyl chloride with an acetoacetic acid ester of an alkyl group having 1 to 4 carbon atoms in the presence of at least one nitrogen-containing basic compound (a) selected from among pyridine compounds, N,N-dialkylanilines and imidazole compounds and from 0.01 to 0.5 mole equivalent, based on the pivaloyl chloride, of a magnesium compound (b) to thereby prepare a pivaloylacetoacetic acid ester and then alcholyzing or alkali-hydrolyzing the pivaloylacetoacetic acid ester to thereby give a pivaloylacetic acid ester having a high purity at a low cost.

Process for producing pivaloyl-acetic acid ester

Process for producing optically active 3,7-dimethyl-6-octenol and process for producing intermediate therefor

Cis-3,7-dimethyl-2,7-octadienylamine containing from 2 to 10% by weight cis-3,7-dimethyl-2,7-octadienylamine is prepared by subjecting a mixture of an alkylamine and isoprene in a molar ratio of 1:4 to 1:4.5 to telomerization at 80 to 100&deg; C. for from 2.5 to 3.5 hours in the presence of an alkyllithium catalyst and/or phenyllithium catalyst.

This invention is concerned with a ruthenium-iodo-optically active bidentate phosphine complex of the formula (I):

Ruthenium-I0D0-optically active phosphine complex

The present invention provides a catalyst which exhibits a high catalytic activity and allows asymmetric reaction in a high asymmetric yield to obtain a reaction product having a high optical purity. The present invention also provides a process for the preparation of an optically active 4-methyl-2-oxetanone having a high optical purity useful as starting material of polymer in a high yield in a short period in the presence of the foregoing catalyst. A novel ruthenium-iodo-optically active phosphine complex is provided, represented by the following general formula (1):

Ruthenium-optically active phosphine complex, process for the

(2R,3R)-3-N-(L-aspartyl)amino-1-(1-methyl-2-norbornyl)-2-butanol and (2R,3R)-3-N-(L-aspartyl)amino-1-(3-methyl-2-norbornyl)-2-butanol as well as a sweetener comprising the same are disclosed. These compounds, which have excellent sweetness characteristics and are stable in acidic aqueous solutions, are highly useful as a sweetener in various fields.

N-(l-aspartyl)amino alcohol derivative and sweetener containing the same

A process for preparing optically active 4-methyl-2-oxetanone which comprises asymmetrically hydrogenating 4-methylene-2-oxetanone in the presence of a ruthenium-optically active phosphine complex. Optically active 4-methyl-2-oxetanone can easily and economically be obtained at high optical purity.

Process for preparing optically active 4-methyl-2-oxetanone

A process for preparing optically active 3-hydroxypyrrolidine derivatives useful as intermediates represented by formula (III): ##STR1## wherein Q represents a substituted or unsubstituted phenyl group; and * indicates an asymmetric carbon atom, comprising reacting an optically active 4-halo-3-hydroxybutane derivative represented by formula (I): ##STR2## wherein * is as defined above; R.sup.1 represents a lower alkyl group or a substituted or unsubstituted phenyl group; and X represents a halogen atom, with a benzylamine derivative represented by formula (II):

Process for preparing optically active 3-hydroxypyrrolidine derivatives

A process for production of an optically active isomer of 2-(tetrahydropyran-2-yloxy)-1-propanol represented by formula (I): ##STR1## is disclosed, which comprises reacting an optically active isomer of a 1-acyloxy-2-propanol represented by formula (II): ##STR2## wherein R is a substituted or unsubstituted aryl group, with 3,4-dihydro-2H-pyran to obtain an optically active isomer of a 1-acyloxy-2-(tetrahydropyran-2-yloxy)propane represented by formula (III): ##STR3## wherein R is as defined above, and hydrolyzing the compound (III) to eliminate the acyl group. The optically active isomer of 2-(tetrahydropyran-2-yloxy)-1-propanol represented by formula (I) is an intermediate for synthesis of pyridobenzoxazine derivatives useful as a synthetic antibacterial agent, particularly an optically active isomer of ofloxacin.

Process for production of optically active

A process for preparing an optically active 3-hydroxybutanoic acid represented by formula (I): ##STR1## wherein: R.sup.1 represents a protective group of carboxylic acid, and

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Kanagawa, Japan

Yoshiki Okeda