Coumarins XI: A total synthesis of (±)-columbianetin

✍ Scribed by M. Shipchandler; T. O. Soine; P. K. Gupta

• Book ID: 102913495
• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: English
• Weight: 578 KB
• Volume: 59
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600590111

✦ Synopsis

The relationship between pH and the mechanism of clindamycin degradation could be summed as follows. Below pH 4 clindamycin degrades via thioglycoside and amide hydrolysis with thioglycoside hydrolysis predominant in the pH range 0.4-4. Above pH 5 clindamycin degrades by conversion to lincomycin and by other reactions such as amide hydrolysis. The extent of lincomycin conversion is dependent on the degree of protonation of the N-methyl-4-propylpyrrolidine moiety. At pH less than 5 where the amine is fully protonated no conversion to lincomycin occurs. Then this process can be detected in the vicinity of p H 5 and its rate increases as pH increases to pH 9 and then becomes constant since the amine function is completely nonprotonated. The overall rate of clindamycin degradation continues to increase with increasing p H above p H 9, however, due to the hydroxide ion dependency of the other degradative routes.