title: Three closely related 4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridines: synthesis, molecular conformations and hydrogen bonding in zero, one and two dimensions.
abstract: In each of 1-(4-fluorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C21H19F4N3O2S, (I), 1-(4-chlorophenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C21H19ClF3N3O2S, (II), and 1-(3-methylphenyl)-5-methylsulfonyl-3-[4-(trifluoromethyl)phenyl]-4,5,6,7-tetrahydro-1H-pyrazolo[4,3-c]pyridine, C22H22F3N3O2S, (III), the reduced pyridine ring adopts a half-chair conformation with the methylsulfonyl substituent occupying an equatorial site. Although compounds (I) and (II) are not isostructural, having the space groups Pbca and P212121, respectively, their molecular conformations are very similar, but the conformation of compound (III) differs from those of (I) and (II) in the relative orientation of the N-benzyl and methylsulfonyl substituents. In compounds (II) and (III), but not in (I), the trifluoromethyl groups are disordered over two sets of atomic sites. Molecules of (I) are linked into centrosymmetric dimers by C-H...π(arene) hydrogen bonds, molecules of (II) are linked by two C-H...O hydrogen bonds to form ribbons of R33(18) rings, which are themselves further linked by a C-Cl...π(arene) interaction, and a combination of C-H...O and C-H...π(arene) hydrogen bonds links the molecules of (III) into sheets. Comparisons are made with the structures of some related compounds.
authors.affiliation: Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
authors.forename: Belakavadi K
authors.initials: BK
authors.lastname: Sagar
authors.affiliation: Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
authors.forename: Kachigere B
authors.initials: KB
authors.lastname: Harsha
authors.affiliation: Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
authors.forename: Hemmige S
authors.initials: HS
authors.lastname: Yathirajan
authors.affiliation: Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru 570 006, India.
authors.forename: Kanchugarakoppal S
authors.initials: KS
authors.lastname: Rangappa
authors.affiliation: Centre for Biological Sciences (Bioinformatics), School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Patna 800 014, India.
authors.forename: Ravindranath S
authors.initials: RS
authors.lastname: Rathore
authors.affiliation: School of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland.
authors.forename: Christopher
authors.initials: C
authors.lastname: Glidewell
keywords: C—Cl...π(arene) interactions; C—H...π(arene) interactions; crystal structure; heterocyclic compounds; hydrogen bonding; molecular conformation; molecular structure; pyrazolo[4,3-c]pyridine; synthesis