Eisai Chemical Co., Ltd.

Takeo Kanai

Yoshio Urawa

Masahiko Tsujii

Akihiko Shimotani

Akio Imai

Katsuhiko Sato

Homare Shinohara

Kazumi Oishi

Described is a protected aminothiazolylacetic acid derivative represented by the following formula (I): ##STR1## wherein A represents a nitrogen atom or a methine group, R.sup.1 and R.sup.2 may be the same or different and individually represent a hydrogen atom, a lower alkyl group or a substituted or unsubstituted aryl group, R.sup.3 represents a lower alkoxy group, a halogenated lower alkoxy group, a triphenylmethoxy group, a lower alkyl group or an acyloxy group, and R.sup.4 represents a halogen atom, a hydroxy group, a lower alkoxy group or a substituted or unsubstituted amino group; and salts thereof; as well as processes for the preparation thereof. The protected aminothaizolylacetic acid derivative according to the present invention is an useful intermediate for introducing a 2-(2-aminothiazol-4-yl)-2-alkoxyiminoacetyl group or a 2-(2-aminotiazol-4-yl)-2-alkenoyl group into a cephem skeleton.

Protected aminothiazolylacetic acid derivatives

A process is provided for the preparation of an aminothiadiazolylacetyl halide derivative represented by the following formula (II): ##STR1## wherein R.sup.1 represents a lower alkyl, cycloalkyl or halogenated lower alkyl group; and R.sup.2 represents an amino-protecting group or a hydrogen atom, or a salt thereof, which process uses as the starting material a compound represented by the following formula (I): ##STR2## wherein R.sup.1 and R.sup.2 have the same meanings as defined above, or a salt thereof.

Process for the preparation of aminothiadiazolylacetyl halide derivtives

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Ibaraki, Japan

Takeo Kanai