| Popis: |
The structure and conformation of the molecules (1RS,2SR,6SR,7SR,8SR)-6,7-dihydroxy-3-oxatricyclo[6.5.0.02,7]tridec-1-yl acetate, (2), and (1SR,2SR,6SR,7RS)-11-oxo-10-oxatricyclo[5.3.1.02,6]undec-2-yl acetate, (4), are illustrated and discussed. Crystals of (2) are triclinic, P\overline{1}, with two molecules in the asymmetric unit which show small but significant differences in conformation. These molecules are joined in ribbons running along a crystallographic direction by a system of bifurcated intra- and intermolecular hydrogen bonds formed by the hydroxy groups. The tricyclic systems in the molecules of both compounds have an anti conformation with cis substitutions at the ring junctions. In (4) the keto group is transoid to the acyclic atoms at the junction of the two five-membered rings (with respect to the plane through the central ring). |
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