(1R,3R,4R,6S)-4-(7-Methoxy-2-oxo-2H- chromen-6-yl)-1-methyl-3,6-dioxa- bicyclo[3.1.0]hexan-2-yl acetate

disorder in main residue; R factor = 0.046; wR factor = 0.136; data-to-parameter ratio = 9.5. In the title compound, C17H16O7, which was isolated from the leaves of Micromelum integerrimum, the furan ring adopts an envelope conformation with the O atom as the flap. An intramolecular C—H O hydrogen bond occurs. The carbonyl O atom is disordered in a 0.57 (8):0.43 (8) ratio. In the crystal, molecules are linked by weak C—H O hydrogen bonds into a C(10) chain along [010]. Related literature Micromelum integerrimum is a shrub in the Rutacae family containing the coumarin molecule, micromelin, as the major chemical constituent (Cassady et al., 1979). Many coumarins including micromelin have been extracted from Rutacae plants, and for some their cytotoxicity has been investigated (Sripisut et al., 2012; He et al., 2001). For previous reports on the isolation of micromelin (micromelumin) from a Northern Queensland collection, an Assamese collection, and a North-east Thailand collection, see: Lamberton et al. (1967); Das et al. (1984); Siridechakorn et al. (2012). For detailed H1 NMR spectroscopic data, see: Das et al. (1984); Siridechakorn et al. (2012). For a phytochemical investigation, see: Siridechakorn et al. (2012). For a closely related micromelin structure, C15H12O6, see: Fun et al. (2011). For hydrogen-bond motifs, see: Bernstein et al. (1995). For puckering parameters, see