N-[2-(3,4-Dimethoxyphenyl)-2-(phenylsulfanyl)ethyl]-2-(2-fluorophenyl)acetamide

The title compound is an intermediate for the synthesis of isoquinoline fluorine analogues. The structure presents a racemic mixture of enantiomers. In the crystal, N—H⋯O hydrogen bonds between neighbouring molecules form chains of molecules along the a-axis direction.

The title compound, C 24 H 24 FNO 3 S, is an intermediate in the synthesis of fluorine containing isoquinoline alkaloids, which crystallizes in the triclinic space group P1 with one molecule in the asymmetric unit. The structure presents a racemic mixture of enantiomers. The C-S-C-C torsion angle between the benzene ring system and the sulfonyl benzene ring is À178.5 (1) . In the crystal, N-HÁ Á ÁO hydrogen bonds between neighbouring molecules form chains of molecules along the a-axis direction.

Structure description
Sulfur-and fluorine-containing molecules play important roles in medicinal chemistry. Sulfur-containing compounds often show a variety of biological activities and serve important functions in applications in the pharmaceutical industry (Bernardi et al., 1985). A variety of sulfur-containing molecules have been isolated from natural sources and play major roles in drug discovery and development. The role of fluorine in drug design and development is expanding rapidly, as more is learned about the unique properties associated with this unusual element and how to deploy it in the pharmaceutical industry. The introduction of fluorine into a molecule can influence conformation, pK a , intrinsic potency, membrane permeability, metabolic pathways, and pharmacokinetic properties (Gillis et al., 2015). Various sulfur-and fluorine-containing molecules have been studied for their applications in medicinal chemistry, with those containing a sulfone group emerging with promising results. Some examples are the recently reported thiochroman-4-one derivatives (Vargas et al., 2017), in which structure-activity relationships have been studied and it has been found that the vinyl sulfone and fluorine moieties play important roles in the biological activity of the molecules (Fig. 1). The literature also reveals that these types of compounds also serve as neuroprotective agents (Woo et al., 2014), exhibit data reports antituberculosis activity (Tiwari et al., 2015) and inhibit prostate cancer (Goa & Spencer, 1998).
Continuing our interest in developing new sulfur-and fluorine-containing C17 S1 C7 C1biologically active alkaloids, we report here the synthesis and characterization of the title compound (Fig. 2) as a racemic mixture. The torsion angle between the benzene ring system and the sulfonyl benzene ring is À178.5 (1) . The C11-C10-C9 angle [117.8 (2) ] is slightly widened in comparison to an sp 3 -hybridized carbon atom; this is probably due to an attractive interaction between the fluorine on the benzene ring and the hydrogen atoms on the benzyl carbon. In the crystal, N-HÁ Á ÁO hydrogen bonds between neighbouring molecules form chains of molecules along the a-axis direction (Table 1; Fig. 3).

Synthesis and crystallization
The title compound was synthesized by the oxidation of N-(2-(3,4-dimethoxyphenyl)-2-(phenylthio)ethyl)-2-(2-fluorophenyl)acetamide (0.229 g, 0.54 mmol) treated with NaIO 4 (0.264, 1.23 mmol) in water (6 ml). The reaction mixture was stirred for 2 h in reflux and then was allowed to cool down at room temperature prior to extractions with DCM (3 Â 20 ml). The solvent in the combined organic layer was removed under vacuum and purified by flash chromatography on silica gel (DCM/MeOH 95:5) to give a pale-yellow solid in 67% yield (0.163 g, 0.36 mmol). Refinement Crystal data, data collection and structure refinement details are summarized in Table 2.

Figure 2
The molecular structure of the title compound with displacement ellipsoids drawn at the 30% probability level. Table 1 Hydrogen-bond geometry (Å , ). Symmetry code: (i) x À 1; y; z.

Figure 1
Structure-activity relationships of thiochroman-4-one derivatives data reports  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. The C-bound H atoms were placed in calculated positions and treated as riding: C-H = 0.95-0.99 A° with U iso (H) = 1.5Ueq(Cmethyl) and 1.2Ueq(C) for other H atoms.