Abstract
Three ring-substituted 3-aryl analogs of 2-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one, namely 3-(4-meth-oxy-phen-yl)-2-phenyl-4H-1,3-benzo-thia-zin-4-one, C21H17NO2S, (I), 2-phenyl-3-[4-(tri-fluoro-meth-yl)phen-yl]-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one toluene hemisolvate, C21H14F3NOS·0.5C7H8, (II), and 3-(3-bromo-phen-yl)-2-phenyl-2,3-di-hydro-4H-1,3-benzo-thia-zin-4-one toluene hemisolvate, C20H14BrNOS·0.5C7H8, (III), were synthesized and their crystal structures determined. The hemisolvates differ in that in (II), the asymmetric unit comprises two molecules of the benzo-thia-zinone compound and a toluene solvent mol-ecule, whereas in (III), the unit comprises one benzo-thia-zinone mol-ecule and a half-occupancy toluene solvent mol-ecule. All crystals are of racemic mixtures of the chiral 2-C atom of the thia-zine moiety, which in all structures has a screw-boat puckering, with the puckering amplitude values within the range 0.575-0.603 Å. In all three structures, the benzene plane of the benzo-thia-zine system makes a dihedral angle in the range 78.60 (5) to 98.40 (5)° with the unsubstituted benzene plane and in the range 70.50 (1) to 121.00 (5)° with the substituted benzene plane. The CF3 substituent group in one of the mol-ecules of (II) shows positional disorder, with an occupancy ratio of 0.57 (3):0.43 (3). In the crystals of (I) and (II), weak inter-molecular C-H⋯O inter-actions are present, giving in (I), mol-ecules arranged in a plane parallel to (010), and in (II), chains along a. In addition, all three structures show weak C-H⋯π inter-actions involving various aromatic rings.
Highlights
Three ring-substituted 3-aryl analogs of 2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one, namely 3-(4-methoxyphenyl)-2-phenyl-4H-1,3-benzothiazin-4one, C21H17NO2S, (I), 2-phenyl-3-[4-(trifluoromethyl)phenyl]-2,3-dihydro-4H1,3-benzothiazin-4-one toluene hemisolvate, C21H14F3NOSÁ0.5C7H8, (II), and 3-(3-bromophenyl)-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one toluene hemisolvate, C20H14BrNOSÁ0.5C7H8, (III), were synthesized and their crystal structures determined
In the crystals of (I) and (II), weak intermolecular C—HÁ Á ÁO interactions are present, giving in (I), molecules arranged in a plane parallel to (010), and in (II), chains along a
We have previously reported the crystal structures of 2,3diphenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one (Yennawar et al, 2014) and three 2-aryl-3-phenyl-2,3-dihydro-4H-1,3benzothiazin-4-ones (Yennawar et al, 2013, 2015)
Summary
We have previously reported the crystal structures of 2,3diphenyl-2,3-dihydro-4H-1,3-benzothiazin-4-one (Yennawar et al, 2014) and three 2-aryl-3-phenyl-2,3-dihydro-4H-1,3benzothiazin-4-ones (Yennawar et al, 2013, 2015). We report the synthesis and crystal structures of three ring-substituted 3-aryl-2-phenyl-2,3-dihydro-4H-1,3-benzothiazin-4-ones, namely the 4-methoxyphenyl compound, (I), the 4-(trifluoromethyl)phenyl compound as the toluene hemisolvate, (II), and the 4bromophenyl compound as the toluene hemisolvate, (III). (II) and (III) differ in that the asymmetric unit of (II) comprises two independent benzothiazinone molecules and one toluene solvent molecule, while that of (III) comprises one benzothiazinone molecule and a half-occupancy toluene solvent molecule. Each compound has been synthesized using the same T3P/pyridine (T3P is 2,4,6tripropyl-1,3,5,2,4,6-trioxatriphosphorinane 2,4,6-trioxide) method that was used for the preparation of the previously mentioned analogous compounds (Yennawar et al, 2013, 2014, 2015)
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