Open AccessFour 2‐aryl‐8,8‐dimethyl‐6,7,8,9‐tetrahydropyrazolo[2,3‐ a ]quinazolin‐6‐ones: isolated molecules, hydrogen‐bonded dimers, and π‐stacked chains of hydrogen‐bonded dimers
Author(s) -
Cruz Silvia,
Quiroga Jairo,
Torre José M. de la,
Cobo Justo,
Low John N.,
Glidewell Christopher
Publication year - 2006
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
eISSN - 1600-5759
pISSN - 0108-2701
DOI - 10.1107/s0108270106017598
Subject(s) - chemistry , hydrogen bond , molecule , ring (chemistry) , stacking , aryl , crystallography , stereochemistry , aromaticity , medicinal chemistry , organic chemistry , alkyl
In each of the three compounds 2‐(4‐chlorophenyl)‐5,8,8‐trimethyl‐6,7,8,9‐tetrahydropyrazolo[2,3‐ a ]quinazolin‐6‐one, C 19 H 18 ClN 3 O, (I), 2‐(4‐methoxyphenyl)‐5,8,8‐trimethyl‐6,7,8,9‐tetrahydropyrazolo[2,3‐ a ]quinazolin‐6‐one, C 20 H 21 N 3 O 2 , (II), and 8,8‐dimethyl‐2‐(4‐methylphenyl)‐6,7,8,9‐tetrahydropyrazolo[2,3‐ a ]quinazolin‐6‐one monohydrate, C 19 H 19 N 3 O·H 2 O, (IV), the non‐aromatic carbocyclic ring adopts a half‐chair conformation, while in 2‐(4‐chlorophenyl)‐8,8‐dimethyl‐5‐phenyl‐6,7,8,9‐tetrahydropyrazolo[2,3‐ a ]quinazolin‐6‐one, C 24 H 20 ClN 3 O, (III), the corresponding ring adopts a conformation intermediate between the envelope and screw–boat forms. The structure of (I) consists of isolated molecules, while that of (II) contains dimers formed by C—H⋯O hydrogen bonds. In (III), dimers formed by C—H⋯O hydrogen bonds are linked into chains by means of an aromatic π–π stacking interaction, while in the monohydrate, (IV), the heterocyclic molecules and the water molecules are linked by O—H⋯O and O—H⋯N hydrogen bonds to form centrosymmetric four‐component aggregates.