Eisai Company, Limited

Eisai Chemical Co., Ltd.

Eisai Chemical

Yoshio Urawa

Toshikazu Shimizu

Tomio Tsurugi

Ken Furukawa

Yoji Yamagishi

Tomio Ichino

Masahiko Tsujii

Akihiko Shimotani

Takeo Kanai

Shizumasa Kijima

Kimio Hamamura

Yoshihiko Hisatake

Yukio Narabe

The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo�4,5-b!pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo�4,5-b!pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous. Further, the biphenyl derivative of the present invention is excellent in reactivity and purity of the product, thus being an intermediate suitable for the industrial production.

Intermediates for imidazopyridine derivatives

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

The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1##

Intermediates for imidazopyridines

The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo-[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous. Further, the biphenyl derivative of the present invention is excellent in reactivity and purity of the product, thus being an intermediate suitable for the industrial production.

Process for the preparation of imidazopyridine derivatives and

The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization.

Sulfonyloxy-biphenylcarboxylic ester derivatives which are intermediates

Process for the preparation of imidazopyridine derivatives

Intermediates for substituted biphenylmethylmidazopyridine angiotensin

The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-b]pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous. Further, the biphenyl derivative of the present invention is excellent in reactivity and purity of the product, thus being an intermediate suitable for the industrial production.

Process for the preparation of biphenyl containing intermediates useful

Process for the preparation of imidazopyridine derivatives, and

A terpene derivative represented by the general formula (I): ##STR1## wherein R.sup.1 represents a lower alkyl group; R.sup.2 represents an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an aryl group, an arylalkyl group or a heteroaryl group; n is 0 or 1 or 2; and the symbol '  ' represents a single or double bond with the proviso that both of the linkages adjacent to each other are not simultaneously single bonds or double bonds which are useful for the preparation of drug, food, perfume and so on, and a process for preparing thereof.

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Ibaraki, Japan

Yoshio Urawa