title: Four N(7)-benzyl-substituted 4,5,6,7-tetrahydro-1H-pyrazolo[3,4-b]pyridine-5-spiro-1'-cyclohexane-2',6'-diones as ethanol hemisolvates: similar molecular constitutions but different crystal structures.
abstract: 3-tert-Butyl-7-(4-chlorobenzyl)-4',4'-dimethyl-1-phenyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-b]pyridine-5-spiro-1'-cyclohexane-2',6'-dione ethanol hemisolvate, C(30)H(34)ClN(3)O(2) x 0.5C(2)H(6)O, (I), its 7-(4-bromobenzyl)- analogue, C(30)H(34)BrN(3)O(2) x 0.5C(2)H(6)O, (II), and its 7-(4-methylbenzyl)- analogue, C(31)H(37)N(3)O(2) x 0.5C(2)H(6)O, (III), are isomorphous, with the ethanol component disordered across a twofold rotation axis in the space group C2/c. In the corresponding 7-[4-(trifluoromethyl)benzyl]- compound, C(31)H(34)F(3)N(3)O(2) x 0.5C(2)H(6)O, (IV), the ethanol component is disordered across a centre of inversion in the space group P\overline{1}. In each of (I)-(IV), the reduced pyridine ring adopts a half-chair conformation. The heterocyclic components in (I)-(III) are linked into centrosymmetric dimers by a single C-H...pi interaction, with the half-occupancy ethanol component linked to the dimer by a combination of C-H...O and O-H...pi(arene) hydrogen bonds. The heterocyclic molecules in (IV) are linked into chains of centrosymmetric rings by C-H...O and C-H...pi hydrogen bonds, again with the half-occupancy ethanol component pendent from the chain. The significance of this study lies in the isomorphism of the related derivatives (I)-(III), in the stoichiometric hemisolvation by ethanol, where the disordered solvent molecule is linked to the heterocyclic component by a two-point linkage, and in the differences between the crystal structures of (I)-(III) and that of (IV).
authors.affiliation: Departamento de Química, Universidad de Nariño, Ciudad Universitaria, Torobajo, Pasto, Colombia.
authors.forename: Silvia
authors.initials: S
authors.lastname: Cruz
authors.forename: Jorge
authors.initials: J
authors.lastname: Trilleras
authors.forename: Justo
authors.initials: J
authors.lastname: Cobo
authors.forename: John N
authors.initials: JN
authors.lastname: Low
authors.forename: Christopher
authors.initials: C
authors.lastname: Glidewell
mesh_terms: D003461:Crystallography; D003510:Cyclohexanes / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry; D006860:Hydrogen Bonding; D015394:Molecular Structure; D011720:Pyrazoles / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*
chemical_list: D003510:Cyclohexanes; D011720:Pyrazoles; D011725:Pyridines; D000431:Ethanol