X-ray study of the hetero ring flexibility in cis-trimethylene- and tetramethylene-1,3-oxazin-2-ones and a cis-trimethylene-1,3-oxazine-2-thione [1]. The structures of cis-5,6-trimethylene-5,6-dihydro-4H-1,3-oxazin-2(3H)-one (I), cis-5,6-trimethylene-5,6-dihydro-4H-1,3-oxazine-2(3H)-thione (II) and 3-methyl-cis-5,6-tetramethylene-3,4,5,6-tetrahydro-1,3-oxazin-2-one (III)

S. Stankovic, Á Kapor, B. Ribár, A. Kálmán, Gy Argay, L. J. Karanovic, G. Stájer, G. Bernáth

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The structures of the title compounds have been established by X-ray crystallography using direct methods. Crystals of compound I (C7H12NO11) are monoclinic, space group P21/c, with a = 12.013(4), b = 6.133(3), c = 9.899(4) Å, β = 100.83(2)°, Z = 4 and Dc = 1.309 g cm-3. Crystals of II (C7C11NOS) are monoclinic, space P21/n, with a = 6.291(4), b = 21.316(8), c = 6.058(1) Å, β = 102.95(3)°, Z = 4 and Dc = 1.319 g cm-3. Crystals of III (C9H12NO2 are also monoclinic, space group P21/c, with a = 6.207(4), b = 14.365(5), c 10.474(4) Å, β = 104.30(5)°, Z = 4 and Dc = 1.242 g cm-3. The structures were refined to R = 0.078 for 909 reflections of I, R = 0.049 for 1372 reflections of II and R = 0.074 for 953 reflections of III. The conformations of the hetero rings have been studied in comparison with those found in the structures of IVVII [2]. A marked influence of the five-membered carbocyclic ring on the puckering of the 1,3-oxazine moiety is shown.

Original languageEnglish
Pages (from-to)45-53
Number of pages9
JournalJournal of Molecular Structure
Issue number1-2
Publication statusPublished - Oct 1985


ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry

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