Crystal and molecular structure of O-(bromoacetyl)tetrahydrodouglanine, C17H25O4Br
The crystal structure of O-(bromoacetyl)tetrahydrodouglanine, C17H25O4Br, a derivative of the sesquiterpene lactone, douglanine, has been determined by an X-ray diffraction study. The crystals are orthohombic, space group P212121, Z= 4 in a unit cell of dimensions, a= 7·657 ± 0·005, b= 13·722 ± 0·004, and c= 16·392 ± 0·004 Å. Intensities of 1497 independent reflections were measured on a diffractometer. The structure was solved by the heavy-atom technique, using Patterson and Fourier syntheses and refined by least-squares techniques to R 7·6% for 1075 observed reflections. Both six-membered rings are in the chair-form. The bond distances and angles are normal and mean standard deviations are of the order of ± 0·02 Å for the bond distances and 0·9° for the bond angles.