Crystal structures of two modifications oftrans-1,3-bis(3,4-dimethoxyphenyl)-2,3-epoxy-1-propanone

trans-1,3-Bis(3,4-dimethoxyphenyl)-2,3-epoxy-1-propanone exhibits dimorphism and crystallizes in a monoclinic form from ethanol and in a trigonal form from chloroform/hexane. The crystal structures of the two modifications were determined by single-crystal X-ray diffraction methods. The monoclinic form crystallizes in space groupP2t/c with\(\dot a = 8.709(2)\),b=7.986(1),c=25.223(4) A, β=94.83(2)°,V=1747.9(6) A andZ=4.R=0.052 for 1236 reflections [I>3σ(I)]. The trigonal form crystallizes in space group\(R\bar 3\) witha=36.048(6),c=8.313(5) A,V=9355(6) A andZ=18 (hexagonal axes).R=0.101 for 1216 reflections [I>3σ(I)]. In the trigonal crystals there are channels in thec-direction with a diameter of approximately 10 A. Possible explanations for the comparatively highR-value are discussed.