title: 6-(4-Fluorophenyl)-8-phenyl-2,3-dihydro-4H-imidazo[5,1-b][1,3]thiazin-4-one: an unusual [6-5] fused-ring system.
abstract: The title compound, C(18)H(13)FN(2)OS, is the first structural example of a [6-5] fused ring incorporating the 2,3-dihydro-4H-imidazo[5,1-b][1,3]thiazin-4-one molecular scaffold. The six-membered 2,3-dihydro-1,3-thiazin-4-one ring adopts an envelope conformation, with the S-CH(2) C atom displaced by 0.761 (2) A from the five-atom plane (all within 0.05 A of the mean plane). The imidazole ring is planar. The phenyl ring is twisted from coplanarity with the imidazole ring by 23.84 (5) degrees and the 4-fluorophenyl ring is twisted by 53.36 (6) degrees , due to a close C(aryl)-H...O=C contact with the thiazin-4-one carbonyl O atom. The primary intermolecular interaction involves a CH(2) group with the F atom [C...F = 3.256 (2) A and C-H...F = 137 degrees ].
authors.affiliation: School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
authors.forename: John F
authors.initials: JF
authors.lastname: Gallagher
authors.forename: Marie Delphine H
authors.initials: MD
authors.lastname: Le Bas
authors.forename: Claire M
authors.initials: CM
authors.lastname: Coleman
authors.forename: Donal F
authors.initials: DF
authors.lastname: O'Shea
mesh_terms: D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D013843:Thiazines / Q000737:chemistry*
chemical_list: C519339:6-(4-fluorophenyl)-8-phenyl-2,3-dihydro-4H-imidazo(5,1-b)(1,3)thiazin-4-one; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007093:Imidazoles; D013843:Thiazines