Synthesis and Characterization of N,N’-(propane-1,2 diyldicarbamothioyl)dibenzamide

Benzoylthioureas have found some interest due to their biological activity [1], spectroscopic and structural properties [2,3], or as synthetic building blocks [4]. Here, we report the convenient preparation of a new representative of this type of compounds. Benzoyl isothiocyanate (1) was prepared by known methods reported in the literature [5]. Benzoyl isothiocyanate (21 ml) was added to a solution of 1,2-diaminopropane (17 ml) in anhydrous acetone. The resulting mixture was refluxed for 6 h. Finally, the mixture was cooled in an ice bath and 1M HCl (250 ml) was added. The yellow precipitate was collected by filtration and it was washed with diethyl ether. The title compound 2 thus obtained was recrystallized from EtOH/CH₂Cl₂.

Color: yellow.

Mp 162-163°C.

Elemental analysis: Found: C, 57.5; H, 5.1; N, 13.9; S, 16.0. Calc. for C₁₉H₂₀N₄S₂O₂: C, 57.0; H, 5.0; N, 14.0; S, 16.0.

¹H NMR: δ (CDCl₃, 400.1 MHz): 11.00 (s, 1H, NH-CO); 10.96 (d, 1H, NH-CO); 9.04 (s, 1H, NH); 8.99 (s, 1H, NH); 7.84–7. 52 (m, 10H, PhH); 5.03–4.98 (m, 1H, CH); 4.19–3.99 (m, 2H, CH₂); 1,46–1,44 (d, 3H, CH₃).

¹³C NMR: δ (CDCl₃, 100.0 MHz): 185.2 (C=S); 164.0 (C=O); 135.6–127.2 (C=C_arom); 47.5 (CH); 46.9 (CH₂); 18.7 (CH₃).

IR (KBr) ν_max/cm^-1: 3350–3300 (N-H), 3161 (C-H_aromatic), 3038 (CH₃), 2935–2859 (C-H_aliphatic), 1980–1835 (C=C), 1677 (C=O), 1540–1258 (C-N), 1189, 1162 (C=S).

UV-vis (CH₂Cl₂, abs): 240; 400.