Rifamycin derivatives having the following structure of general formula I (both hydroquinone and corresponding quinone (C1-C4) forms): or its salts, hydrates or prodrugs thereof; wherein a preferred R1 comprises hydrogen or acetyl and a prefered R2 comprises hydrogen, methyl or other lower alkyls; wherein asterik (*) denotes the carbon bearing the chiral center, wherein absolute configuration is assigned as R or S. Methods of preparation of the aforementioned rifamycin derivatives are also described. The compounds exhibit antimicrobial activities, including activities against drug-resistant microorganisms.