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

Yield:74257-00-4 48%

Reaction Conditions:

with triethylamine in 1,4-dioxane for 1.5 h;Cooling with ice;

Steps:

1-(Mesitylenesulfonyl)-3-nitro-1,2,4-triazole (3)
An oven dried 1.0 l round-bottomedflask containing a magnetic stir bar was equipped with a Claisen adapter. 3-Nitro-1,2,4-triazole (19.5 g, 0.171 mol), dry dioxane (200 ml) and triethylamine (1.0 equiv., 17.3 g,0.171 mol) was transferred to the reaction flask and the solution was cooled in an ice-bathwith magnetic stirring.47 The Claisen adapter was fitted with a 200 ml pressure-equalizingaddition funnel, containing a dioxane solution (150 ml) of mesitylenesulfonyl chloride(37.4 g, 0.171 mol). The solution of mesitylenesulfonyl chloride was added dropwise overa period of approx. 0.5 h and the final suspension was stirred for an additional 1 h andthen warmed to rt. After removal of the precipitated Et3N·HCl by filtration, the filtratewas concentrated in vacuo to give a yellow solid, which was dissolved in dichloromethane(150 ml) and the solution was washed with water (150 ml).48 The organic layer was driedover anhydrous Na2SO4 and evaporated in vacuo to give a yellow solid. Recrystallizationfrom boiling toluene (20-30 ml) followed by washing with ice-cold toluene and dryingovernight at 1.9 mmHg, provided 24-25 g (46%-48%) of the title compound as light yellow solid,49 mp. 131C-133C (lit.37 130C-132C). Rf = 0.23 (20% hexane in CH2Cl2, UV);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): 3126, 2983, 2947, 1597.Anal. Calcd. for C11H12N4O4S: C, 44.59; H, 4.08; N, 18.91. Found: C, 44.69; H,3.88; N, 18.72. The purity of the product (96%) established by RP-HPLC, tR = 8.41 min(254 nm).

References:

Petersen, Rico;Jensen, Jakob F.;Nielsen, Thomas E. [Organic Preparations and Procedures International,2014,vol. 46,# 3,p. 267 - 271]

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