Structures of 4-phenylcyclohexa[e][1,3]oxazine-4H-2(3H)-thione and 2-chlorophenyl-4H-4-phenylcyclopenta[e][1,3]oxazine: an X-ray study

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Abstract

The structures of 4-phenylcyclohexa[e][1,3]oxazine-4H-2(3H)-thione (1) and 2-chlorophenyl-4H-4-phenylcyclopenta[e][1,3]oxazine (2) were established by X-ray crystallography from diffractometer data. Compound 1 (C14H17NOS) crystallizes in the monoclinic space group P21/c (No. 14), with a = 10.917(1), b = 10.596(1), c = 11.663(2) Å, β = 95.38(1)°, V = 1343.3(5) Å3, Z = 4, Dc = 1.223 g cm-3 and μ(Cu Kα) = 1.958 mm-1. Compound 2 (C19H18NOCl) also crystallizes in the monoclinic space group P21/c, with a = 5.435(2), b = 8.681(1), c = 33.224(3) Å, β = 90.29(2)°, V = 1567.4(9) Å3, Z = 4, Dc = 1.321 g cm-3 and μ(Cu Kα) = 2.168 mm-1. The crystal structures were solved by direct methods and refined to R = 0.041 for 1 and R = 0.047 for 2, using 2031 and 1932 observed reflections, respectively. In both structures, the condensed bicyclic skeleton is cis fused and exhibits an O-in conformation which contains an axial oxygen atom, whereas the C4 phenyl group is trans to the annelation hydrogens and equatorial to the hetero ring. However, the conformations of the hetero rings differ substantially. In 1 the oxazine ring assumes a half-chair (1-monoplanar) form with the annelation carbon atoms nearly symmetrically above (Δ = 0.339(2) Å for C4A) and below (Δ = -0.308(2) Å for C8A) the best plane of the remaining four ring atoms, whereas in 2 there is an almost perfect envelope (1,2-diplanar) conformation with C4A on the flap (Δ = 0.296(3) Å). These conformations are compared with those of the analogous 1,3-oxazine derivatives.

Original languageEnglish
Pages (from-to)269-276
Number of pages8
JournalJournal of Molecular Structure
Volume328
Issue numberC
DOIs
Publication statusPublished - Dec 1 1994

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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