The orthosomycins,a new family of antibiotics

A new family of antibiotics, the orthosomycins, which contain in their structures one or more orthoester linkages associated with carbohydrate residues, is described. Examples of orthosomycin antibiotics include flambamycin (1), the everninomicins -B2a, -C2b, -D2c and -2(3), hygromycin B4a, the destomycins -A4b, -B5 and -C4c, the antibiotics SS-56-C4d, A-396-I4e and, more recently, the avilamycins -A49a and -C49b. The structural elucidation of these orthosomycin antibiotics is discussed, with emphasis on structural similarities and differences, together with a commentary on their biological activities and structure-activity relationships.