pubmed-article:21581393 | pubmed:abstractText | In the title compound, C(13)H(10)F(3)N(3)O(5), a derivative of andrographolide, the five-membered ring adopts an envelope conformation, while the non-planar six-membered ring has a chair conformation. An intra-molecular C-H?F hydrogen bond results in the formation of a non-planar six-membered ring adopting a twisted conformation. In the crystal structure, inter-molecular C-H?O hydrogen bonds link the mol-ecules into centrosymmetric dimers. | lld:pubmed |