The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 20, 2000
Filed:
Aug. 28, 1998
Takeda Chemical Industries, Ltd., Osaka, JP;
The Kitasato Institute, Tokyo, JP;
Abstract
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.