ABSTRACT
Clarithromycin (CAS number: 81103-11-9) is the 6-O-methyl derivative of erythromycin (Morimoto et al., 1984; Fernandes et al., 1986). The replacement of the hydroxyl substituent by a methoxy group in position 6 renders the molecule resistant to acidic hydrolysis, improving its oral bioavailability compared to that of erythromycin (see Chapter 59, Erythromycin). The empirical formula is C38H69NO13 and the molecular weight is 748.0; the molecular structure is shown in Figure 61.1. Molecular structure of clarithromycin. Chemical stability in acid medium is a result of the replacement of the hydroxyl group in position 6 of erythromycin by a methoxy group. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315152110/08d8042d-9481-4a8d-8c27-9bd589f6de6b/content/fig61_1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
