7-Chloro-3-(4-methylbenzenesulfonyl)pyrrolo[1,2-c]pyrimidine

The dihedral angle between the pyrrolo[1,2-c]pyrimidine ring system and the benzene ring is 80.2 (9)°. In the crystal, inversion dimers linked by pairs of C—H⋯O interactions generate (16) loops. Several aromatic π–π stacking interactions between the pyrrolo[1,2-c]pyrimidine rings, as well as separately between the pyrrolo and pyrimidine groups [shortest centroid–centroid separation = 3.5758 (14) Å], help to consolidate the packing.


Structure description
Pyrrolo [1,2-c]pyrimidines are a class of fused heterocycles of interest for their biological activity, electrochemical properties, and as components of natural products (Tatu et al., 2018). As part of our studies in this area, we now report the crystal structure of the title compound, C 14 H 11 N 2 O 2 SCl (Fig. 1). We believe that this is the first crystal structure to be reported of a pyrrolo [1,2-c]pyrimidine and one of the few unsymmetrical 'diaryl sulfones' to be described.
In the crystal, a weak C14-H14BÁ Á ÁO2 hydrogen bond (Table 1) links two molecules together in a ring face-ring face arrangement (Fig. 2). This packing motif was also observed by Sime & Woodhouse (1974) in the crystal structure of diphenyl sulfone and by Colquhoun et al. (2002) in the crystal structure of poly(1,4-phenylenesulfone). Several aromaticstacking interactions between the pyrrolo[1,2-c]pyrimidine rings as well as separately between the pyrrolo and pyrimidine groups ( Table 2) are observed and help to consolidate the packing.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. Table 1 Hydrogen-bond geometry (Å , ).

Figure 2
Packing diagram of the title compound viewed along the a axis direction showing inversion dimers linked by pairs of weak C-HÁ Á ÁO interactions. Table 2 distances (Å ) and angles ( ) for the title compound.

Figure 1
The molecular structure of the title compound, showing 50% probability ellipsoids.

Funding information
This work was supported by Dartmouth College. JPJ acknowledges the NSF-MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.

data-2
IUCrData (2020). 5, x200382 Refinement. All of the H atoms were placed in their calculated positions and then refined with atom-H lengths of 0.93 Å (CH); 0.96 Å (CH 3 ) using the riding model with U iso (H) = 1.2 (CH) or 1.5 times U eq (CH 3 ) of the parent atom. The idealized methyl group was refined as a rotating group.