(5,7-Dimethyl-2-oxo-2H-chromen-4-yl)methyl pyrrolidine-1-carbodithioate

In the title compound, C17H19NO2S2, the 2H-chromene ring system is almost planar, with a maximum deviation of 0.044 (2) Å, and the pyrrolidine ring adopts an envelope conformation. The dihedral angle between the 2H-chromene system and the planar part of the pyrrolidine ring is 83.65 (8)°. A weak intramolecular C—H⋯S hydrogen bond occurs. The crystal structure features C—H⋯O hydrogen bonds and π–π interactions, with a centroid–centroid distance of 3.5728 (16) Å.

In the title compound, C 17 H 19 NO 2 S 2 , the 2H-chromene ring system is almost planar, with a maximum deviation of 0.044 (2) Å , and the pyrrolidine ring adopts an envelope conformation. The dihedral angle between the 2H-chromene system and the planar part of the pyrrolidine ring is 83.65 (8) .

Devarajegowda Comment
Coumarins are a class of naturally occurring lactones. A number of coumarins have been isolated in recent years, mainly from plant sources and extracts of these have been employed as traditional medicines in different areas of the world.
In our present work, we have been able to link a dithiocarbamate group at the C-4 methylene carbon and it was deemed of considerable interest to study the effect of this group on the total solid state conformation of the molecule. The synthesized compound was screened for antimicrobial, antidiabetic, DNA binding and DNA cleavage studies.In continuation of our interest in the crystal structures of coumarin derivatives (Kumar et al., 2012;Kant et al., 2012), we report here the crystal structure of the title compound.

Experimental
All the chemicals used were of analytical reagent grade and were used directly without further purification.4-Bromomethyl coumarin required for the synthesis of the target molecule was synthesized according to an already reported procedure involving Pechmann cyclization of phenols with 4-bromoethyl acetoacetate (Shastri et al., 2004) and sodium pyrrolidine-1-carbodithioate was synthesized according to the reported procedure (Vasilliev & Polackov, 2000). A mixture of 2.67 g (0.01 mol) of 5,7-dimethyl-4-bromomethyl coumarin and1.69 g (0.01 mol) of sodium pyrrolidine-1carbodithioate in 30 ml dry alcohol was stirred for 24 h at room temperature (the reaction was monitored by TLC). The solvent was evaporated and the resulting solid was extracted twice with a dichloromethane-H 2 O mixture.The organic layer was dried over anhydrous CaCl 2 and evaporation of the organic solvent gave the title compound.The compound was recrystallized from an ethanol-chloroform mixture. Colour: colourless. Yield 88%, m.p.443 K.

Figure 1
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms are shown as spheres of arbitrary radius. Dashed lines indicate intramolecular hydrogen bonds. Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 > 2σ(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.