title: Imino Diels-Alder adducts. II. Two pyrano[3,2-c]quinolines.
abstract: 8-Chloro-9-fluoro-5-phenyl-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline and 10-chloro-9-fluoro-5-phenyl-3,4,4a,5,6,10b-hexahydro-2H-pyrano[3,2-c]quinoline, both C18H17ClFNO, are diastereoisomers, formed as the result of the imino Diels-Alder reactions of N-benzylideneanilines with 3,4-dihydro-2H-pyran. The crystal structures reveal the stereochemistry of the pyran ring, which is endo/exo to the quinoline ring system formed in the cycloaddition step. In both structures, the pyran ring adopts a chair conformation, while the nitrogen-containing heterocyclic ring prefers a half-chair conformation. The structures differ essentially in the relative orientation of the ring junction H atoms.
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
authors.initials: VV
authors.lastname: Narayana Reddy
mesh_terms: D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007097:Imines / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011804:Quinolines / Q000737:chemistry*
chemical_list: D007097:Imines; D011804:Quinolines