title: Isomeric pyrazolo[3,4-d]pyrimidine-based molecules: disappearance of dimerization due to interchanged substitutions.
abstract: In 5-benzyl-1,7-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d]pyrimidine-4,6-dione, C(14)H(14)N(4)O(2), which crystallizes in space group P 1 macro, weak intermolecular C[bond]H...O hydrogen bonds generate dimers. The isomeric compound 1-benzyl-5,7-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d]pyrimidine-4,6-dione, C(14)H(14)N(4)O(2), crystallizes in space group P2(1)/n, and shows no such dimerization. Instead, it exhibits C[bond]H...pi interactions with the phenyl ring. In both structures, the molecules are linked by aromatic pi-pi-stacking interactions.
authors.affiliation: Medicinal Chemistry Division, Central Drug Research Institute, Lucknow 226 001, India.
authors.forename: Kamlakar
authors.initials: K
authors.lastname: Avasthi
authors.forename: Diwan S
authors.initials: DS
authors.lastname: Rawat
authors.forename: Tilak
authors.initials: T
authors.lastname: Chandra
authors.forename: Ashoke
authors.initials: A
authors.lastname: Sharon
authors.forename: Prakas R
authors.initials: PR
authors.lastname: Maulik