| 摘要 |
NEW MATERIAL:A compound of formula I [R1 is H, acetyl; one of R2 and R3 is H, the other is formula II (R4 is alkylene which may be substituted with hydroxyl), or both of them are formula II]. EXAMPLE:2'-O-Acetylneospiramycin I. USE:Antibacterial effective on gram-positive bacteria. PREPARATION:For example, spiramycin I is dissolved in chloroform containing pyridine and acetic anhydride is added to the solution, as the mixture is cooled with ice and stirred to give 2'-O-acetylspiramycin I. The product is dissolved in hydrochloric acid, its pH is adjusted to 1.9, then the solution is stood at 42 deg.C to effect the reaction. Then, sodium bicarbonate is added to the reaction mixture to adjust the pH to 7.0, the mixture is diluted with water, extracted with chlorform. The extract is concentrated under reduced pressure to give the compound of formula I .
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