Furan oligomers and β-carbolines from terrestrial streptomycetes

2,5-Bis(hydroxymethyl)furan monoacetate (3) and 2,5 -bis(hydroxymethyl)furan diacetate (4) were obtained as new natural products from an ethyl acetate extract of the terrestrial Streptomyces sp. isolate GW11/1695. Another Streptomyces isolate. GW21/1313, delivered a dimer (6) and a trimer (7) of (hydroxymethyl)furfural. The latter strain also produced 4-hydroxy-2-(5 -(hydroxymethyl)furan-2-ylmethylene)-5-methylfuran-3-one (5), perlolyrin (8), and two new beta-carboline derivatives, 9 and 10. 2,5-Bis(hydroxymethyl)furan diacetate (4) exhibited weak cytotoxic activity against brine shrimp larvae.