3-tert-Butyl-4-(4-nitrophenyl)-1-phenyl-1H-pyrazolo[3,4-b]pyridine

Abstract

Mol­ecules of the title compound, C22H20N4O2, are linked by paired C—H⋯O hydrogen bonds into centrosymmetric R22(18) dimers and these dimers are linked into chains by paired C—H⋯π(arene) hydrogen bonds.

(E)-N-{[6-Chloro-4-(4-chlorophenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridin-5-yl]methylene}benzene-1,2-diamine: a three-dimensional framework structure built from only two hydrogen bonds

“…However, the space group accommodates equal numbers of the two conformational enantiomers, and the choice of the selected asymmetric unit has no chemical significance. The bond distances (Table 1) in the heterocyclic fragment of the molecule, which show the same pattern as found in similar pyrazolo [3,4-b]pyridines (Low et al, 2002(Low et al, , 2007Abonia et al, 2005;Quiroga et al, 2009), having due regard to the differences between the peripheral substituents, are consistent with the occurrence of aromatic-type electronic delocalization within the pyridine ring and strong bond fixation in the pyrazole ring. Likewise, there is strong bond fixation, as expected, in the spacer unit between the pyridine and the aminophenyl rings.…”

“…Firstly, (IV) and (V) both crystallize as stoichiometric monosolvates with dimethylformamide (Low et al, 2007). Secondly, unlike (I), which crystallizes in the Sohnke space group Pna2 1 , compounds (II)-(VI) all crystallize in the centrosymmetric space groups P1 [for (II) (Low et al, 2002), (III) (Abonia et al, 2005) and (IV) (Low et al, 2007)] or C2/c [for (V) (Low et al, 2007) and (VI) (Quiroga et al, 2009)]. In addition, the crystal structures of (II)-(VI) all contain C-HÁ Á Á(arene) hydrogen bonds, whereas such interactions are absent from the structure of (I).…”

Seven 5-benzylamino-3-tert-butyl-1-phenyl-1H-pyrazoles: unexpected isomorphisms, and hydrogen-bonded supramolecular structures in zero, one and two dimensions

“…There are four of these dimeric units in each unit cell, each lying across a different rotation axis, but there are no direction-specific interactions between the dimers; in particular, aromaticstacking interactions are absent. The supramolecular aggregation in compound (II) is thus significantly different from that in the isomorphous 4-methoxybenzyl analogue (VIII) (Abonía et al, 2007), where a single C-HÁ Á ÁN hydrogen bond links molecules related by translation into simple C(9) chains: N-HÁ Á Á and C-HÁ Á Á interactions are, however, absent from the structure of (VIII).…”

“…the first intermediates isolated in a synthetic pathway developed as a route to new fused heterocyclic compounds containing the pyrazole unit (Castillo et al, 2009). The next step in this pathway requires the reduction of the imine derivatives to give the corresponding 5-arylmethylamino-3tert-butyl-1-phenyl-1H-pyrazoles, and we report here the molecular and supramolecular structures of seven compounds of this type, namely 5-benzylamino-3-tert-butyl-1-phenyl-1Hpyrazole, (I), and its 4-methylbenzyl, 4-(trifluoromethyl)benzyl, 4-chlorobenzyl, 4-bromobenzyl and 4-nitrobenzyl analogues, denoted (II)-(VI), and the 3,4,5-trimethoxybenzyl analogue, (VII), which we compare with the 4-methoxybenzyl derivative, (VIII), whose structure was reported several years ago (Abonía et al, 2007) (see scheme below and Fig. 1).…”

“…4-Methylbenzyl compound (II) and its 4-methoxy analogue, (VIII) (Abonía et al, 2007), are effectively isomorphous, with close correspondence between the two sets of atomic coordinates, although the cell dimensions are slightly larger for (VIII) [a = 10.9665 (14) Å and c = 30.976 (6) Å ]. For neither of these compounds was it possible to establish whether the correct space group for the crystal selected for data collection The molecular structures of compounds (I)-(VIII), showing the atom-labelling schemes: (a) compound (I), (b) compound (II), (c) compound (III), (d) compound (IV), (e) compound (V), (f) compound (VI) and (g) the two independent molecules of compound (VII).…”