Takeda Chemical Industries, Inc.

The Kitasato Institute

Miichiro Arita

Yukio Mizuno

Satoshi Omura

Masayasu Kato

A method of producing an N-demethyl-N-isopropyl-8,9-anhydroerythromycin A-6,9-hemiacetal or a salt thereof, characterized in that an N-demethylerythromycin A or a salt thereof is reacted with an isopropylating agent and subsequently treated under acidic conditions, and a method of producing a substantially pure crystal of an 8,9-anhydroerythromycin A-6,9-hemiacetal derivative represented formula (VI): ##STR1## wherein R.sup.1 and R.sup.2, whether identical or not, represent an alkyl having 1 to 6 carbon atoms, an alkenyl having 2 to 6 carbon atoms or an alkynyl having 2 to 6 carbon atoms; R.sup.3 represents hydrogen or a hydroxyl group; one of R.sup.4 and R.sup.5 represents hydrogen and the other represents a hydroxyl group, or R.sup.4 and R.sup.5 bind together to represent O.dbd.; R.sup.6 represents hydrogen or a hydroxyl group that may be substituted for; R.sup.7 represents hydrogen or a hydroxyl group; or a salt thereof, characterized in that a crude crystal of said 8,9-anhydroerythromycin A-6,9-hemiacetal derivative or a salt thereof is recrystallized as a solvation product from hydrated isopropanol.

Method of producing erythromycin derivative

Method for producing ethers

A method of producing diethanolamine derivatives or acid salts thereof according to the reaction scheme: ##STR1## wherein X stands for a leaving group; and R.sup.1 stands for an alkylcarbamoyl group, which provides an industrially advantageous method of preparing the subject matter useful as an antiarrhythmic agent.

Growing community of inventors

Nara, Japan

Miichiro Arita