The anthrapyran antibiotic AH-1763 IIa (1) was isolated in 1997 by Uyeda et al.[1] from a culture broth of Streptomyces cyaneus. Compound 1 contains the 4H-anthra [1, 2-b] pyran-4, 7, 12-trione nucleus 2 found in the pluramycin antibiotics (Figure 1).[2] These antibiotics, first described in 1956 by Umezawa et al.,[3] are most commonly isolated from terrestrial Streptomyces sp. and are known for their potent anticancer activity arising from the ...
