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Article Dans Une Revue Acta Crystallographica Section C : Crystal Structure Communications [1968-2013] Année : 2011

Concomitant polymorphism in stereoselective synthesis of a $\beta$-benzyl $\beta$-hydroxy aspartate analogue

Résumé

Two concomitant polymorphs, (I) and (II), of a beta-benzyl- beta-hydroxyaspartate analogue [systematic name: dibenzyl 2-benzyl-2-hydroxy-3-(4-methylphenylsulfonamido)succinate], C32H31NO7S, crystallize from a mixture of ethyl acetate and cyclohexane at ambient temperature. The structure of (I) has triclinic (P1) symmetry and that of (II) monoclinic (P21/c) symmetry. Both crystal structures are made up of a stacking of homochiral racemic dimers (2S,3S and 2R,3R) which are internally connected by a similar R2 2(9) hydrogen-bonding pattern consisting of intermolecular N--H...O and O--H... O hydrogen bonds. The centroid of the racemic dimer lies on an inversion centre. The main structural difference between the two polymorphs is the conformational orientation of two of the four aromatic rings present in the molecule. Polymorph (II) is found to be twinned by reticular merohedry with twin index 3 and twin fractions 0.854 (1) and 0.146 (1).

Dates et versions

hal-00606460 , version 1 (06-07-2011)

Identifiants

Citer

Sofiane Mekki, Valérie Rolland, Salima Bellahouel, Arie Van-Der-Lee, Marc Rolland. Concomitant polymorphism in stereoselective synthesis of a $\beta$-benzyl $\beta$-hydroxy aspartate analogue. Acta Crystallographica Section C : Crystal Structure Communications [1968-2013], 2011, 67, pp.o301-o305. ⟨10.1107/S0108270111024632⟩. ⟨hal-00606460⟩
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