N-[ 3-( Prop-1-yn-1-yl ) phenyl ] benzenesulfonamide

In 1932, a drug called Prontosil was discovered by the pharmaceutical division of IG Farbenindustrie, an industrial conglomerate of German companies, including Bayer Company. It was found to be very successful treating several diseases in humans, provoked by Staphylococcus and Streptococcus. Prontosil was the first antibacterial drug, with life-saving capability, to be used systematically for the treatment of bacterial infections in the body. It belongs to a family of compounds called sulfa drugs or sulfonamides. In the 1940s and 1950s, most of the sulfa drugs were replaced by penicillin and other drugs, which proved to be more effective against more types of bacteria. However, nowadays, some sulfa drugs such as sulfamethoxazole, in combination with trimethoprim (co-trimoxazole), are still used extensively to inhibit the growth of bacteria that produce opportunistic infections in patients with AIDS, and bacterial infections such as pneumonia, bronchitis and infections of the urinary tract, ears and intestines (Brumfitt & Hamilton-Miller, 1993). As part of our studies in this area we now report the synthesis of of the title sulfanilamide derivative, 1, and its crystal structure. This compound, has been found to be very effective against Staphylococcus aureus and Escherichia coli, and minimal inhibitory concentrations (MIC) of 12.5 mg ml 1 and 25.0 mg ml 1 have been obtained respectively (Cabezas & Arias, 2019). Received 30 July 2019 Accepted 26 August 2019

In the title sulfanilamide derivative, C 15 H 13 NO 2 S, which shows significant activity against Staphylococcus aureus and Escherichia coli, the dihedral angle between the planes of the aromatic rings is 62.15 (19) and the four-coordinate S atom adopts an almost ideal tetrahedral geometry. In the crystal, N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds link the molecules into a three-dimensional network.

Structure description
In 1932, a drug called Prontosil was discovered by the pharmaceutical division of IG Farbenindustrie, an industrial conglomerate of German companies, including Bayer Company. It was found to be very successful treating several diseases in humans, provoked by Staphylococcus and Streptococcus. Prontosil was the first antibacterial drug, with life-saving capability, to be used systematically for the treatment of bacterial infections in the body. It belongs to a family of compounds called sulfa drugs or sulfonamides. In the 1940s and 1950s, most of the sulfa drugs were replaced by penicillin and other drugs, which proved to be more effective against more types of bacteria. However, nowadays, some sulfa drugs such as sulfamethoxazole, in combination with trimethoprim (co-trimoxazole), are still used extensively to inhibit the growth of bacteria that produce opportunistic infections in patients with AIDS, and bacterial infections such as pneumonia, bronchitis and infections of the urinary tract, ears and intestines (Brumfitt & Hamilton-Miller, 1993).
As part of our studies in this area we now report the synthesis of of the title sulfanilamide derivative, 1, and its crystal structure. This compound, has been found to be very effective against Staphylococcus aureus and Escherichia coli, and minimal inhibitory concentrations (MIC) of 12.5 mg ml À1 and 25.0 mg ml À1 have been obtained respectively (Cabezas & Arias, 2019).

Figure 3
A synthetic scheme for the preparation of the title compound.

Synthesis and crystallization
The title compound, 1, was synthesized by treatment of 3iodoaniline, 2, with benzenesulfonyl chloride, 3, in the presence of pyridine, at room temperature to obtain, after purification by column chromatography (ether:hexane, 40:60), iodosulfonamide, 4, in 75% yield. This aromatic iodide 4, was treated with propyne, under Sonogashira's reaction conditions (Sonogashira et al., 1975), using CuI and (Ph 3 P) 2 PdCl 2 as catalysts, (Fig. 3). After purification by column chromatography, using a solvent mixture of hexane:ethyl acetate (75:25), compound 1 was isolated in 70% yield, and with an overall yield of 53%. The product was recrystallized from ethyl acetate solution at room temperature to result in lightyellow blocks of the title compound.

Refinement
Crystal data, data collection and structure refinement are summarized in Table 2.

N-[3-(Prop-1-yn-1-yl)phenyl]benzenesulfonamide
Crystal data 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. All hydrogen atoms were placed geometrically and refined using a riding-atom model approximation, with C-H = 0.95-1.00 Å, with U iso (H) = 1.2U eq (C). A rotating group model was used for the methyl groups.