Yamanouchi Pharmaceutical Company Ltd.

Hideki Arima

Kiyoshi Murase

Minoru Okada

Yasuo Isomura

Toshiyasu Mase

Toichi Takenaka

Kenichi Tomioka

Yukiyasu Murakami

Tadao Kojima

Kazuharu Tamazawa

Kiyoshi Takanobu

Kunihiro Niigata

Yoso Numasaki

Shinichiro Kobayashi

A process is provided for producing diastereoisomer A or a pharmaceutically acceptable acid addition salt of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(1-benzylpyrrolidin-3-yl) ester 5-methyl ester which comprises subjecting a mixture of diastereoisomers A and B of 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(1-benzylpyrrolidin-3-yl) ester 5-methyl ester to column chromatography using silica gel as a carrier and a mixture of ethyl acetate and acetic acid as an eluant, and then separating the acetate of diastereoisomer A from the eluate, or treating the acetate with a base, or further treating the resulting diastereoisomer A with a pharmaceutically acceptable acid.

Dihydropyridine-3, 5-dicarboxylic acid ester derivatives

A dextro-rotatory optical isomer of diastereoisomer A of (.+-.)-2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-(1-benzylpyrrolidin-3-yl)ester 5-methyl ester is provided having the formula ##STR1## and wherein the melting point of the hydrochloride of the dextro-rotatory optical isomer is 223.degree. to 230.degree. C. (decomp.), or a pharmaceutically acceptable acid addition salt thereof.

Dihydropyridine-3,5-dicarboxylic acid ester derivatives

The diastereoisomer A of a dihydropyridine-3,5-dicarboxylic acid ester derivative is provided as well as its pharmaceutically acceptable acid addition salts. The invention further discloses a process for producing the compounds and their use as medicaments in imparting vasodilating activity.

A catechol derivative represented by the formula ##STR1## The compounds of this invention are useful for the prophylaxis and treatment for various allergic diseases, ischemic heart diseases and inflammations caused by slow reacting substance of anaphylaxis (SRS-A), since the compounds inhibit very potently the formation and release of SRS-A.

Catechol derivatives and pharmaceutical compositions thereof for

Novel 2-phenylimidazo[2,1-b]benzothiazole compounds shown by general formula I ##STR1## and the salts thereof, a process of producing the compounds, and pharmaceutical compositions containing the compounds. The compounds of this invention act on immune response, in particular, suppress a delayed type hypersensitivity reaction, and are useful as antiallergic agents, antirheumatics, therapeutic agents for autoimmune diseases, and suppressants of rejection at tissue transplantation and skin graft.

2-Phenylimidazo[2,1-b]benzothiazole compounds, salts thereof, process of

A novel 2-hydroxyoxanilic acid derivative shown by the following formula ##STR1## or a salt thereof. This compound possesses an immunoregulatory action and is useful as an antiallergic agent, an antiasthmatic, an antirheumatic, a carcinostatic agent, a therapeutic agent for autoimmune disease, and a suppressant of rejection at the tissue transplantation and skin graft.

Growing community of inventors

Tokyo, Japan

Hideki Arima