Daiichi Pharmaceutical Co., Ltd.

Daiichi Seiyaku Co., Ltd.

Takasago International Corporation

Kabushiki Kaisha Toshiba

Toshihiro Fujiwara

Tutomu Ebata

Hidenori Kumobayashi

Yukio Sato

Osamu Watanabe

Yoshiki Okeda

Kazuaki Ikeda

Masataka Fukuda

Akio Tachikawa

Toshihiro Matsuura

Hideaki Tsurumi

Hisao Fujihashi

Propoxybenzene derivatives represented by the following formula ##STR1## wherein Ra represents a nitro group, an amino group which may have a protecting group or an --NHCH.dbd.C(COO--C.sub.1-6 -Alkyl).sub.2 group, Rb represents a hydrogen atom, a protecting group for the hydroxyl group or a substituted sulfonyl group and Xa and Xb, which may be the same or different, each represents a halogen atom, and processes for preparation thereof are disclosed. These derivatives are useful in preparing antibacterial agents.

Propoxybenzene derivatives and process for preparing the same

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

The invention relates to a process for producing a (.+-.)-3-alkyl-3,4-dihydro-2H-[1,4]benzoxazine derivate of formula (II) by stepwise racemization procedure. ##STR1## The invention further provides a process for optical resolution through the formation of a salt between a (.+-.)-benzoxazine compound and an optically active form of camphor-10-sulfonic acid. Without requiring the conventional expensive resolution reagents, this process not only assures production of an optically active isomer of compound (II) in high purity but also permits reuse of the optical resolution reagent.

Optical resolution of benzoxazines

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Tokyo, Japan

Toshihiro Fujiwara