In the course of our screening for small molecule modulators of erythropoietin gene expression, two novel sesquiterpene tropolones and pycnidone were isolated from a culture of OS-F69284 (ATCC 74390). Their structures were elucidated by extensive 1H and 13C NMR spectroscopic studies and chemical reactions. These compounds induced erythropoietin gene expression 5-fold at a concentration of 1-1.6 microM.