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The title compound [generic name: (—)-phenprocoumon], C18H16O3, monoclinic, P21. Z = 4 with two molecules/asymmetric unit, a= 7·171 (1), b = 17·751 (5), c = 11·752 (2) Å, β = 92·58 (2)°, V = 1494 Å3, Dc = 1·28, d0 = 1·30 (2) g cm-3 is pseudoisostructural with the crystalline racemate as suggested by a similarity in cell constants and symmetry. Structural differences involve small translations and where the racemate crystal contains layers of (—) and layers of (+) enantiomers, the (—) crystal contains one layer nearly identical with the (—) layer in the racemate while the 01olecules in the other layer adopt a different conformation so that packing is similar to that in the (+) layer of the racemate. Already high thermal motion in the racemate is dramatically increased in the enantiomeric structure which has a larger cell volume. Hydrogen bonding occurs along the a direction with O···O distances of 2·617 (5) and 2·587 (6) Å. The final R is 0·094 on 3060 counter-collected data.


Pharmaceutical chemistry

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Copyright 1976 International Union of Crystallography. The original published version of this article may be found at



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Journal Article