title: Imino Diels-Alder adducts. XII. Two pyrano[3,2-c]quinolines.
abstract: The crystal structures of pyranoquinolines 9-fluoro-5-phenyl-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline, C18H18FNO, and 9-methyl-5-phenyl-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline, C19H21NO, are isomorphous. In both structures, the pyran ring is exo to the six-membered N-heterocyclic ring formed in the cycloaddition step. The torsion angles across the phenyl linkage for the two structures are -91.2 (1) and -88.3 (2) degrees. The striking feature in both crystal packings is that they do not contain the expected conventional hydrogen bonds, in spite of the presence of good hydrogen-bonding functionalities. Possible C-H...pi interactions are, however, observed.
authors.affiliation: Laboratory of X-ray Crystallography, Indian Institute of Chemical Technology, Hyderabad 500 007, India. ravikumar_iict@yahoo.co.in
authors.forename: K
authors.initials: K
authors.lastname: Ravikumar
authors.forename: B
authors.initials: B
authors.lastname: Sridhar
authors.forename: M
authors.initials: M
authors.lastname: Mahesh
authors.forename: V V Narayana
authors.initials: VV
authors.lastname: Reddy
mesh_terms: D018360:Crystallography, X-Ray; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D011804:Quinolines / Q000737:chemistry*
chemical_list: D007097:Imines; D011804:Quinolines