Acta Crystallographica Section C

Crystal Structure Communications

Volume 62, Part 10 (October 2006)


organic compounds



sk3047 scheme

Acta Cryst. (2006). C62, o625-o627    [ doi:10.1107/S0108270106036900 ]

Chalcone epoxide intermediates in the syntheses of lignin-related phenylcoumarans

V. Langer, S. Li and K. Lundquist

Abstract: Compounds (2R*,3S*)-1-(3,4-dimethoxyphenyl)-3-{3-methoxy-2-[(2R*)-tetrahydropyran-2-yloxy]phenyl}-2,3-epoxy-1-propanone, C23H26O7, (I), and trans-1-(3,4-dimethoxyphenyl)-3-[3-methoxy-2-(methoxymethoxy)phenyl]-2,3-epoxy-1-propanone, C20H22O7, (II), were obtained on epoxidation of chalcones. The stereochemistries of (I) and (II) were elucidated. In both compounds, the substituents on the oxirane ring are trans-oriented. Compound (I) was obtained together with a diastereometric form that differs from (I) with respect to the configuration of the asymmetric C atom in the tetrahydropyran group. The geometries of the substituted oxirane rings of (I) and (II) are very similar. The hydrogen-bonding patterns, mediated via weak C-H...O interactions, differ considerably. The crystal structures of (I) and (II) are compared with those of related chalcone epoxides. The conversion of (I) and (II) into lignin-related phenylcoumarans is discussed.

Formula: C23H26O7 and C20H22O7


hkldisplay filedownload file

Structure factor file (CIF format) (178.4 kbytes)
[ doi:10.1107/S0108270106036900/sk3047Isup2.hkl ]
Contains datablock I


hkldisplay filedownload file

Structure factor file (CIF format) (160.9 kbytes)
[ doi:10.1107/S0108270106036900/sk3047IIsup3.hkl ]
Contains datablock II


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