Isomorphous methyl- and chloro-substituted small heterocyclic analogues obeying the chlorine-methyl (Cl-Me) exchange ruleThis paper is dedicated to the memory of Professor M. A. Viswamitra on the occasion of the 12th anniversary of his death.

摘要

The two new isomorphous structures [3-methyl-4-(4-methylphenyl)-1-phenyl-6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridin-5-yl](thiophen-2-yl)methanone, C26H18F3N3OS, (I), and [4-(4-chlorophenyl)-3-methyl-1-phenyl-6-trifluoromethyl-1H-pyrazolo[3,4-b]pyridin-5-yl](thiophen-2-yl)methanone, C25H15ClF3N3OS, (II), are shown to obey the chlorine-methyl exchange rule. Both structures show extensive disorder, treatment of which greatly improves the quality of the description of the structures. In addition, it is worth noting that the presence of extensive disorder may make it difficult to detect the isomorphism automatically during data-mining procedures (such as searches of the Cambridge Structural Database).