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

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

doi:10.1107/s2056989019013781

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.

Highlights

Compounds with a 2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4one scaffold have shown anticancer (Arya et al, 2014), antibacterial (Shreedhara et al, 2017), and glycosidase inhibitory (Li et al, 2012) bioactivity
We report the syntheses and structures of two solvated analogs containing a substituent on the C-phenyl ring: 2-(4fluorophenyl)-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one as a toluene hemisolvate, 1, and 2-(4-nitrophenyl)3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one as a mixed propanol–water solvate, 2
The 1,3-thiazine ring is in an envelope pucker conformation according to the puckering parameters [Q = 0.6016 (16) A, = 115.35 (16), and ’ = 220.50 (18)] calculated by PLATON (Spek, 2009), with atom C1 displaced from the other atoms

Summary

Chemical context

Compounds with a 2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4one scaffold have shown anticancer (Arya et al, 2014), antibacterial (Shreedhara et al, 2017), and glycosidase inhibitory (Li et al, 2012) bioactivity. These compounds feature a pyridine ring fused to a thiazine ring. We reported the synthesis and structure of 2,3-diphenyl-2,3-dihydro-4Hpyrido[3,2-e][1,3]thiazin-4-one (Yennawar et al, 2014). We report the syntheses and structures of two solvated analogs containing a substituent on the C-phenyl ring: 2-(4fluorophenyl)-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one as a toluene hemisolvate, 1, and 2-(4-nitrophenyl)3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-one as a mixed propanol–water solvate, 2. Symmetry codes: (i) Àx; Ày þ 2; Àz þ 1; (ii) Àx þ 1; y À 12; Àz þ 32

Structural commentary

Database survey

Synthesis and crystallization