Crystal structures of two solvated 2-aryl-3-phenyl-2,3-di-hydro-4 H-pyrido[3,2- e][1,3]thia-zin-4-ones

Hemant P Yennawar; Eric N Thompson; Jennie Li; Lee J Silverberg

doi:10.1107/S2056989019013781

Crystal structures of two solvated 2-aryl-3-phenyl-2,3-di-hydro-4 H-pyrido[3,2- e][1,3]thia-zin-4-ones

Acta Crystallogr E Crystallogr Commun. 2019 Oct 22;75(Pt 11):1689-1693. doi: 10.1107/S2056989019013781. eCollection 2019 Nov 1.

Authors

Hemant P Yennawar¹, Eric N Thompson², Jennie Li², Lee J Silverberg²

Affiliations

¹ Department of Biochemistry and Molecular Biology, 108 Althouse Laboratory, Pennsylvania State University, University Park, PA 16802, USA.
² Pennsylvania State University, Schuylkill Campus, 200 University Drive, Schuylkill Haven, PA 17972, USA.

Abstract

The synthesis and crystal structures of 2-(4-fluoro-phen-yl)-3-phenyl-2,3-di-hydro-4H-pyrido[3,2-e][1,3]thia-zin-4-one toluene hemisolvate (1), C₁₉H₁₃FN₂OS·0.5C₇H₈, and 2-(4-nitro-phen-yl)-3-phenyl-2,3-di-hydro-4H-pyrido[3,2-e][1,3]thia-zin-4-one iso-propanol 0.25-solvate 0.0625-hydrate (2), C₁₉H₁₃N₃O₃S·0.25C₃H₇O·0.0625H₂O, are reported. Both are racemic mixtures (centrosymmetric crystal structures) of the individual com-pounds and incorporate solvent mol-ecules in their structures. Compound 2 has four thia-zine mol-ecules in the asymmetric unit. All the thia-zine rings in this study show an envelope pucker, with the C atom bearing the substituted phenyl ring displaced from the other atoms. The phenyl and aryl rings in each of the mol-ecules are roughly orthogonal to each other, with dihedral angles of about 75°. The extended structures of 1 and 2 are consolidated by C-H⋯O and C-H⋯N(π), as well as T-type (C-H⋯π) inter-actions. Parallel aromatic ring inter-actions (π-π stacking) are observed only in 2.

Keywords: C—H⋯π interactions; crystal structure; envelope pucker; pyridothiazinone.