Clarithromycin monohydrate: a synchrotron X-ray powder study

In the crystal structure of the title compound, clarithromycin (CAM) monohydrate, C38H69NO13·H2O, the water molecule behaves as a proton donor and is hydrogen bonded to the hydroxy O atom of the CAM cladinose ring. The hydroxy O atom also behaves as a proton donor, forming an intermolecular hydrogen bond with one of the hydroxy groups of the 14-membered aglycone ring. The CAM molecules are linked through these hydrogen bonds into chains running parallel to the c axis.