Dimethyl 5,6,7-trimethoxy-2-methyl-1,2-dihydroquinoline-2,4-dicarboxylate

In the title compound, C17H21NO7, the dihydropyridine ring assumes a screw-boat conformation. In the crystal, intermolecular C—H⋯O hydrogen bonds link the molecules, forming supramolecular chains running along the b axis.

In the title compound, C 17 H 21 NO 7 , the dihydropyridine ring assumes a screw-boat conformation. In the crystal, intermolecular C-HÁ Á ÁO hydrogen bonds link the molecules, forming supramolecular chains running along the b axis.

Experimental
The title compound was synthesized by the literature method (Waldmann et al., 2008). 3,4,5-dimethoxyaniline (100 mg, 1 eq) was dissolved in chloroform (1.5 ml) in a screw-capped test tube and Bi(OTf) 3 (5 mol%, 0.05 eq) was added to the mixture. The mixture was stirred at room temperature for 4 h until the starting material was completely consumed as monitored by TLC. The resultant residue was directly purified by flash chromatography on silica (EtOAc:Cylohexane 2:98) gave in 83% yield as a yellow solid. Recrystallized over pentane and ethyl acetate (70:30) gave yellow crystalline solid R f 0.16 (2:1 Cyclohexane/EtOAc) mp 394-395 K. Fig. 1. The molecular structure of the title compound with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

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 supplementary materials sup-3 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1 0.5908 (