1-(Mesitylene-2-sulfonyl)-3-nitro-1,2,4-triazole

773-64-8

24807-55-4

74257-00-4

An oven-dried 1.0-liter round-bottomed flask equipped with a magnetic stirring bar was assembled with a Claisen adapter. To the reaction flask was added 3-nitro-1,2,4-triazole (19.5 g, 0.171 mol), anhydrous dioxane (200 mL), and triethylamine (17.3 g, 0.171 mol, 1.0 eq.), and the solution was cooled to 0°C. A 200 mL pressure-equalizing dosing funnel was assembled through the Claisen adapter, and a dioxane solution (150 mL) of homotrimethylbenzenesulfonyl chloride ( 37.4 g, 0.171 mol) of dioxane solution (150 mL) to the funnel. Slowly add the homotrimethylbenzenesulfonyl chloride solution dropwise to the reaction mixture. After the dropwise addition was completed, the reaction mixture was continued to be stirred for 0.5 hours, followed by warming to room temperature and continued stirring for 1 hour. After completion of the reaction, the precipitated triethylamine hydrochloride was removed by filtration and the filtrate was concentrated under reduced pressure to give a yellow solid. The solid was dissolved in dichloromethane (150 mL) and the organic layer was washed with water (150 mL). The organic layer was dried with anhydrous sodium sulfate, filtered and the solvent evaporated under reduced pressure to give a yellow solid. Recrystallization by boiling toluene (20-30 mL) followed by washing with ice-cold toluene and drying overnight at 1.9 mmHg gave 1-(2-trimethylbenzenesulfonyl)-3-nitro-1,2,4-triazole 24-25 g (46%-48% yield) as a pale yellow solid with a melting point of 131°C-133°C (literature values 130°C-132°C). Thin Layer Chromatography (TLC) Rf = 0.23 (unfolding agent: dichloromethane solution of 20% hexane, UV detection).1H NMR (300 MHz, CDCl3) δ: 8.84 (s, 1H), 7.07 (s, 2H), 2.69 (s, 6H), 2.34 (s, 3H).13C NMR (75 MHz, CDCl3) δ. 162.9, 147.5, 145.2, 142.5, 133.0, 127.9, 23.2, 21.3. IR (solid) νmax: 3126, 2983, 2947, 1597 cm-1. Calculated elemental values (C11H12N4O4S): C, 44.59; H, 4.08; N, 18.91. Measured values: C , 44.69; H, 3.88; N, 18.72. The purity of the product was determined to be 96% by reversed-phase high-performance liquid chromatography (RP-HPLC), with a retention time of tR = 8.41 min (detection wavelength 254 nm).