3-tert-Butyl-1-(4-chlorophenyl)-7,7-dimethyl-5,6,7,8-tetrahydropyrazolo[3,4-b]quinolin-5-one: centrosymmetric dimers generated by C—H...π(arene) hydrogen bonds

Abstract

Molecules of the title compound, C22H24ClN3O, are linked by two pairs of C—H⋯π(arene) hydrogen bonds into centrosymmetric dimers.

3-(4-Methoxyphenyl)-7,7-dimethyl-1,6,7,8-tetrahydropyrazolo[3,4-b]quinolin-5-one: a chain of centrosymmetric rings built from N—H...N and C—H...π(arene) hydrogen bonds

“…1), synthesized using microwave irradiation in the absence of solvent. The structures of several analogous compounds have been reported recently, including those of (II), in both triclinic (Low et al, 2003) and monoclinic polymorphs (Mera et al, 2005), (III) (Low et al, 2004) and (IV) (Low et al, 2005), but in none of compounds (II)±(IV) is there an NÐH bond at pyrazole atom N1, as found in compound (I). Hence, the supramolecular aggregation in (I) is necessarily different from those found in (II)±(IV).…”

“…By contrast, in the triclinic polymorph of (II), which crystallizes with Z H = 2 in the space group P1 (Low et al, 2003), each type of molecule forms a distinct chain built from a combination of CÐHÁ Á ÁO and CÐHÁ Á Á% hydrogen bonds. In compound (III), the molecules are linked by a single CÐHÁ Á ÁN hydrogen bond to form simple C(6) chains (Low et al, 2004), while in compound (IV) the molecules are linked into isolated centrosymmetric dimers by two distinct CÐ HÁ Á Á% hydrogen bonds (Low et al, 2005). Thus, no two members of this series show the same pattern of supramolecular aggregation, con®rming that such aggregation is very sensitive to the details of the substituents on the heterocyclic ring system.…”

A monoclinic polymorph of 3,7,7-trimethyl-1-phenyl-5,6,7,8-tetrahydro-1H-pyrazolo[3,4-b]quinolin-5-one

“…2). We may note here that the exactly corresponding pair of CÐH bonds act as donors to aryl and pyrazole rings in the analogous chloro-substituted compound 3-tert-butyl-1-(4-chlorophenyl)-7,7-dimethyl-5,6,7,8-tetrahydropyrazolo[3,4-b]quinolin-5-one, (III), but such that H6A is donor to the aryl ring and H8A is donor to the pyrazole ring in a cyclic centrosymmetric dimer (Low et al, 2005).…”