(Z)-N-tert-Butyl-2-(4-methoxyanilino)-N′-(4-methoxyphenyl)-2-phenylacetimidamide

In the crystal of the title compound, C26H31N3O2, pairs of N—H⋯O hydrogen bonds link molecules, forming inversion dimers, which enclose an R 2 2(20) ring motif. One N atom does not form hydrogen bonds and lies in a hydrophobic pocket with closest intermolecular contacts of 4.196 (2) and 4.262 (2) Å.

In the crystal of the title compound, C 26 H 31 N 3 O 2 , pairs of N-HÁ Á ÁO hydrogen bonds link molecules, forming inversion dimers, which enclose an R 2 2 (20) ring motif. One N atom does not form hydrogen bonds and lies in a hydrophobic pocket with closest intermolecular contacts of 4.196 (2) and 4.262 (2) Å .

Comment
The title compound was prepared as a secondary product of the three component Ugi reaction (Saha et al., 2013). The central C1-C22 single bond has four bulky substituents arranged, roughly, as if pointing at the corners of a tetrahedron.
Pairs of hydrogen bonds between N2 and O1 [3.170 (1) Å] connect two molecules across an inversion center, creating a cavity around the inversion center with a diameter of about 5 Å. The closest contact across the inversion center involving atoms not involved in the hydrogen bonding is 3.151 (3) Å between the hydrogen bonded to C3 and its symmetry equivalent (symmetry transformation -x + 1, -y + 2, -z + 2). The hydrogen bonding graph set is R 2 2 (20). Nitrogen N3 is unusual in that, although protonated, it does not form hydrogen bonds with acceptor atoms. Instead, it lies in a hydrophobic cavity with closest intermolecular contacts of 4.196 (2) Å and 4.262 (2) Å to C15 and C16 respectively.

Experimental
The compound was synthesized as previously reported [compound 5a in (Saha et al., 2013)]. The crude residue was purified by silica gel column chromatography using (10-30%) ethylacetate-hexane to obtain the pure product. The pure compound was dissolved in 50% ethylacetate-hexane and kept at room temperature for 2 days during which crystals formed.

Refinement
All hydrogen atoms were visible in a difference Fourier map and, except for H2 were added at calculated positions. Bond distances are set to 0.95 Å for aromatic carbon-hydrogen bonds, 0.98 Å for methyl group carbon-hydrogen bonds and 0.88 Å for nitrogen-hydrogen bonds. Thermal parameters for hydrogen atoms were set to 1.2 times the isotropic equivalent thermal parameter of the atom to which the hydrogen atom is bonded, except for methyl group hydrogen atoms where the thermal parameter was set to 1.5 times the isotropic equivalent thermal parameter of the carbon atom the hydrogen atom is bonded to. The positional and isotropic thermal parameters of H2 were refined.  The molecular structure of the title compound. Non-hydrogen atoms are shown as 50% probability ellipsoids.    Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.