Lawesson's reagent → dihydro-2,2,5,5-tetramethyl-4-methylaminomethylene-3(2H)furanthione

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Reaction Steps

A mixture of dihydro-2,2,5,5-tetramethyl-4-methylaminomethylene-3(2H)furanone (3.2 g, 18 mmol) and Lawesson's Reagent (3.8 g, 9.4 mmol) in 40 mL of DME was stirred for 30 min. at room temperature. The solvents were evaporated from the homogeneous orange solution. The residue was taken up in a small volume of methylene chloride and eluted through a short column of 1/1 silica gel/basic alumina with methylene chloride. The solvent was evaporated to leave a yellow solid. Recrystallization from CH2Cl2 /hexanes gave 2.5 g of dihydro-2,2,5,5-tetramethyl-4-methylaminomethylene-3(2H)furanthione as an orange solid. An analytically pure sample was made by chromatographing a small amount on the Chromatotron (Silica 1/1 EtOAc/hexanes): mp 115°-117° C.; Anal. Calc'd for C10H17NOS: C, 60.30; H, 8.54; N, 7.04; S, 16.08. Found: C, 60.27; H, 8.62; N, 7.04; S, 16.15.

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