1-Isobutyl-8,9-dimethoxy-3-phenyl-5,6-dihidro- imidazo[5,1-a]isoquinolin-2-ium chloride

The molecular salt, C23H26N2O2 + Cl , was obtained from 1-isobutyl-8,9dimethoxy-3-phenyl-5,6-dihydroimidazo[5,1-a]isoquinoline, which was synthesized by cyclocondensation of -benzoylamino-methyl-N-[2-(3,4-dimethoxyphenyl)ethyl]valeramide in the presence of phosphoryl chloride. The tetrahydropyridine ring adopts a twist–boat conformation. In the crystal structure, centrosymmetric dimers are formed by N—H Cl and C—H Cl hydrogen bonds.


Structure description
The relevance of a wide range of potent biological activities of natural and synthetic isoquinoline alkaloids is interesting for the synthesis of new isoquinoline compounds. In nature, there are compounds that contain condensed imidazole and isoquinoline rings, for example, cribrostatin 6.

Figure 1
Reaction scheme for the preparation of the title compound.

Figure 2
The molecular structure of the title compound, showing the atomnumbering scheme. Displacement ellipsoids are drawn at the 30% probability level. The N-HÁ Á ÁCl hydrogen bond is shown as a dashed line.

Figure 3
Formation of a centrosymmetric dimer in the crystal structure of the title compound. N-HÁ Á ÁCl hydrogen bonds are shown as dashed lines.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2.

Funding information
Funding for this research was provided by the Academy of Sciences of the Republic of Uzbekistan (grant No. VA-FA-F-6-010).

data-1
IUCrData ( Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. 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 > 2sigma(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. The H atoms bonded to C atoms were placed geometrically (with C-H distances of 0.98 Å for CH, 0.97 Å for CH 2 , 0.96 Å for CH 3 and 0.93 Å for C ar ) and included in the refinement in a riding motion approximation, with U iso (H) = 1.2U eq (C) [U iso (H) = 1.5U eq (C) for methyl H atoms]. The H atom of N2 was located in a difference Fourier synthesis and refined with a N2-H1 distance = 0.79 (3) Å.