Crystal structure of N′-[2-(benzo[d]thiazol-2-yl)acetyl]-4-methylbenzenesulfonohydrazide

In the title compound, the hydrazide N atom bonded to the C=O group is planar, whereas that bonded to the SO2 group is pyramidally coordinated. The interplanar angle between the ring systems is 40.71 (3)°. In the crystal, molecules are connected by N—H⋯O=C and N—H⋯Nthiazole hydrogen bonds, forming ribbons parallel to the b axis.


Chemical context
Benzothiazoles are versatile heterocyclic compounds with potential pharmaceutical applications (Elgemeie & Aal, 1986). Various benzothiazoles have been used as anti-inflammatory, antimicrobial and analgesic agents and as laser dyes (Elgemeie, 1989). This has led to an increasing interest in benzothiazole derivatives in the area of drug design and discovery (Elgemeie et al., 2000). As a part of our research work on new syntheses of benzothiazoles as chemotherapeutic agents (Elgemeie et al., 2017), we have previously reported the synthesis of 2-arylbenzothiazoles that later found applications as anticancer agents and are presently in clinical use for various diseases (Elgemeie & Elghandour, 1990). We report here the new compound N 0 -(2-(benzo[d]thiazol-2-yl)acetyl)-4methylbenzenesulfonohydrazide (1), which was prepared by the reaction of 2-(benzo[d]thiazol-2-yl)acetohydrazide with ptoluenesulfonyl chloride in the presence of pyridine at room temperature. The structure of (1) was determined on the basis of its spectroscopic data and elemental analysis (see Experimental). In order to establish the structure of the product unambiguously, its crystal structure was determined.

Structural commentary
The X-ray analysis confirms the exclusive presence of the form (1) in the solid state (Fig. 1). The molecular dimensions may be regarded as normal (Table 1); the torsion angles defining the conformation of the chain connecting the ring systems are also given in this Table. The bond lengths C2-S1 and C2-N3 in the heterocycle correspond well with the average values of 1.750 (15) and 1.200 (14) Å found in the Cambridge Structural Database (Version 5.38; Groom et al., 2016) for 375 examples of this ring system (unsubstituted benzo ring, carbon-substituted at C2). Nitrogen N1 displays a planar geometry, whereas N2 is pyramidal [they lie 0.014 (7) and 0.337 (8) Å , respectively, outside the plane of their substituents]. Hydrogen atom H01 is antiperiplanar to O3 and H02 to O2 across the N1-C9 and N2-S2 bonds, respectively. The interplanar angle between the ring systems is 40.71 (3) .

Supramolecular features
Molecules are connected by two pairs of classical hydrogen bonds across inversion centres, to form ribbons parallel to the b axis (Table 2, Fig. 2). A C-HÁ Á ÁO interaction connects the molecules by c-axis translation (not shown in the Figure), forming layers parallel to (100).

Figure 2
Packing diagram of compound (1), viewed perpendicular to the bc plane. Hydrogen bonds are drawn as thick dashed lines. H atoms not involved in hydrogen bonds have been omitted for clarity.

Figure 1
The structure of compound (1) in the crystal, with displacement ellipsoids at the 50% probability level.

Synthesis and crystallization
A solution of p-toluenesulfonyl chloride (1.90 g, 0.015 mol) in pyridine (10 ml) was added gradually to a stirred solution of 2-(benzo[d]thiazol-2-yl)acetohydrazide (2.07 g, 0.01 mol) in pyridine (10 ml) at 273 K. The reaction mixture was then stirred at room temperature for 3 h (TLC control). After the reaction was completed, the mixture was poured into icewater with continuous stirring and neutralized with 1 N HCl solution to pH 7.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. NH hydrogen atoms were refined freely. The methyl hydrogen atoms were not well defined and so were refined as a hexagon of half-occupied sites with C-H = 0.98 Å (AFIX 127). Other hydrogen atoms were included using a riding model starting from calculated positions (C-H aromatic = 0.95, C-H methylene 0.99 Å ) with U iso (H) = 1.2U eq (C).