Patent ID: 6077943
Filing Date: 2000-06-20
Classification: C07H

Abstract:
A method of producing a substantially pure crystal of an 8,9-anhydroerythromycin A-6,9-hemiacetal derivative represented by formula (VI): ##STR15## 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 which may be substituted; R.sup.7 represents hydrogen or a hydroxyl group; or a salt thereof, said method comprising recrystallizing a crude crystal of said 8,9-anhydroerythromycin A-6,9-hemiacetal derivative or a salt thereof as a salvation product from an isopropanol/water mixed solvent wherein each of the isopropanol and the water is used in a volume about 1 to 20 times, relative to said 8,9-anhydroerythromycin A-6,9-hemiacetal derivative or a salt thereof, and the ratio of the isopropanol to the water is about 1:0.5 to 1:3.