Rhodopyran, a carboxylated hexahydrocyclopenta[ <i>b</i> ]pyran from <i>Rhodococcus</i>

A new bicyclic metabolite, rhodopyran ( 1 ), was isolated from the culture broth of Rhodococcus sp. strain RD066637. The planar structure was elucidated by 1D/2D NMR analyses and HRMS spectrometry, and the relative configuration was assigned from vicinal coupling constants and NOESY correlations, while the absolute configuration remains undetermined. Rhodopyran represents a structurally unusual carboxylated hexahydrocyclopenta[ b ]pyran and expands the known metabolite diversity of Rhodococcus , highlighting Rhodococcus as a source of uncommon natural-product scaffolds.