Crystal structure of 3-{1-[(1-allyl-1H-indazol-6-yl)amino]ethylidene}-6-methyl-2H-pyran-2,4(3H)-dione

In the title compound, C18H17N3O3, the dihedral angle between the planes of the indazole ring system [maximum deviation = 0.012 (1) Å] and the pyran-2,4-dione ring is 54.03 (6)°. An intramolecular N—H⋯O hydrogen bond closes an S(6) ring. The same H atom also participates in an intermolecular N—H⋯O hydrogen bond, which generates an inversion dimer. The dimers are linked by weak C—H⋯O contacts, thereby forming a three-dimensional network.


1997
). This has incited researchers to develop innovative methods in their synthesis (Paul, et al., 2014).
The two fused five-and six-membered rings (N1/N2/C1 to C7), part of the molecule of the title compound, are almost planar, with the maximum deviation of 0.012 (1) Å arising from atom N1. The fused rings system is nearly perpendicular to the allyl group (C8 C9 C10) as shown in Fig. 1 (torsion angle C9 C8 N1 C7 = 88.9 (2)°). Moreover, the dihedral angle between the indazole system and the plan through the atoms forming the pyran-2 ring (C12 to C16O) is 54.03 (6)°.
In the crystal, molecules are connected through N-H···O hydrogen bonds in the way to build dimers which are linked by weak C-H···O contacts, forming a three-dimensional network as shown in Fig.2 and Table 2.
The combined organic extracts were dried over MgSO 4 , filtered, and concentrated. The resulting residue was purified by flash chromatography (eluted with Ethyl acetate: Hexane 4:6). The title compound was recrystallized from the solvent mixture ethyl acetate/hexane to yield yellow blocks (yield: 85%, m.p.: 392 K).

S3. Refinement
H atoms were located in a difference map and treated as riding with C-H = 0.96 Å, C-H = 0.97 Å, C-H = 0.93 Å, and N-H = 0.90 Å for methyl, methylene, aromatic CH and NH respectively. All hydrogen with U iso (H) = 1.2 U eq (methylene,aromatic, NH) and U iso (H) = 1.5 U eq for methyl.

Figure 1
Molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level.

Figure 2
Partial crystal packing for the title compound showing N3-H3N···O3, C6-H6···O1 and C8-H8A···O1 hydrogen bonds as dashed lines.  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.