Crystal structure of 4-(6-chloro-4-oxo-4H-chromen-3-yl)-2-methylamino-3-nitro-4H,5H-pyrano[3,2-c]chromen-5-one chloroform monosolvate

In the title compound, C23H14Cl4N2O7, the pyran ring has an envelope conformation with the methine C atom as the flap. The chromene rings are almost planar (r.m.s. deviations of 0.027 and 0.018 Å) and their mean planes are inclined to one another by 85.61 (10)°. The mean planes of the pyran ring and the chromene ring fused to it are inclined to one another by 7.41 (13)°. The molecular structure is stabilized by an intramolecular N—H⋯O hydrogen bond, generating an S(6) ring motif. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(12) ring motif. The dimers are linked by pairs of C—H⋯O hydrogen bonds, enclosing R 2 2(18) ring motifs, forming chains along [010]. Within the chains there are C—H⋯π interactions. The chains are linked via slipped parallel π–π interactions, forming a three-dimensional structure [the shortest inter-centroid distance is 3.7229 (19) Å].

Cg4 is the centroid of the C2-C7 ring.

S2. Synthesis and crystallization
A three component coupling reaction, involving 4-hydroxycoumarin (0.81 g, 5 mmol), 6-chloro-4-oxo-4H-chromene-3carbaldehyde (0.87 g, 5 mmol) and NMSM (0.74 g, 5 mmol), was carried out in EtOH at room temperature (3 h) in the presence of triethylamine (0.1eq) as catalyst. Upon completion of the reaction, the mixture was filtered, and washed with ethanol to obtain the desired product as a white solid. Using this combination of ethanol and triethylamine gave an excellent result with a shorter than normal reaction time and an overall yield of 83 %. The title compound was recrystallized from chloroform giving colourless block-like crystals.

S3. Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. The N and C-bound H atoms were positioned geometrically and allowed to ride on their parent atoms: N-H = 0.86 Å, C-H = 0.93-0.98 Å with U iso (H) = 1.5U eq (C) for methyl H atoms and 1.2U eq (N,C) for all other H atoms.

Figure 1
The molecular structure of the title compound, with atom labelling. Displacement ellipsoids are drawn at the 30% probability level. The intramolecular N-H···O hydrogen bond is shown as a dashed line (see Table 1 for details) supporting information sup-3 Acta Cryst. (2015). E71, o512-o513

Figure 2
The crystal packing of the title compound, viewed along the a axis. The hydrogen bonds are shown as dashed lines (see Table 1 for details). H atoms not involved in these interactions have been omitted for clarity.  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.