Acta Crystallographica Section C

Crystal Structure Communications

Volume 60, Part 4 (April 2004)

sk1707 scheme

Acta Cryst. (2004). C60, o265-o269 [doi:10.1107/S0108270104004159]

Molecular conformation and supramolecular aggregation in two fused pyrazoles: -stacked R $_{\bf 2}^\bf 2}$ (6) dimers in 2,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, and sheets of alternating R(12) and R(48) rings in 3-tert-butyl-4',4'-dimethyl-1-phenyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-b]pyridine-5-spiro-1'-cyclohexane-2',6'-dione

J. N. Low, J. Cobo, J. Mera, J. Quiroga and C. Glidewell

Abstract: In 2,8,8-trimethyl-6,7,8,9-tetrahydropyrazolo[2,3-a]quinazolin-6-one, C₁₃H₁₅N₃O, (I), the heterobicyclic system is planar and exhibits peripheral ten [bold pi] -electron delocalization. In 3-tert-butyl-4',4'-dimethyl-1-phenyl-4,5,6,7-tetrahydro-1H- pyrazolo[3,4-b]pyridine-5-spiro-1'-cyclohexane-2',6'-dione, C₂₃H₂₅N₃O₂, (II), the pyrazole ring exhibits marked bond fixation, while the reduced pyridine ring adopts a half-chair conformation. Molecules of (I) are linked into centrosymmetric (6) dimers by a single C-HN hydrogen bond [HN = 2.50 Å, CN = 3.3397 (17) Å and C-HN = 148°], and these dimers are linked into chains by a single [bold pi] - stacking interaction. In (II), the combined action of one N-HO hydrogen bond [HO = 2.40 Å, NO = 3.2248 (15) Å and N-HO = 157°] and one C-HO hydrogen bond [HO = 2.48 Å, CO = 3.407 (2) Å and C-HO = 164°] links the molecules into sheets built from alternating centrosymmetric (12) and (48) rings; there is a weak C-HN interaction [HN = 2.60 Å, CN = 3.5149 (18) Å and C-HN = 154°] between molecules in adjacent sheets.

Formula: C₁₃H₁₅N₃O and C₂₃H₂₉N₃O₂

Online 20 March 2004


	Structure factor file (CIF format) (127.3 kbytes) Contains datablock I

	Structure factor file (CIF format) (225.1 kbytes) Contains datablock 849

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