Prenderol → 5,5-Diethyl-1,3-dioxane-2-thione

Participants

Reaction Steps

The thiocarbonate 1 was prepared by a variation of the thiocarbonylation procedure developed by Corey and Hopkins. To a three-necked round-bottomed flask, equipped with a mechanical stirrer and an additional funnel, was placed 2,2-diethyl-1,3-propanediol (15.86 g, 120 mmol), 4-dimethylaminopyridine (DMAP, 29.32 g, 240 mmol) and 120 mL of toluene under an atmosphere of nitrogen. The mixture was allowed to stir at room temperature until a homogeneous solution was reached. The mixture was cooled to 0-5° C. and then a solution of thiophosgene (9.43 mL, 120 mmol) in 90 mL of toluene was added dropwise via the additional funnel over a period of 90 min. This resulted in the formation of a bright orange DMAP-thiophosgene complex. After the completion of addition, the reaction mixture was allowed to stir for an hour at 0-5° C. and then slowly warmed to room temperature. The reaction mixture was allowed to stir at room temperature for an additional hour and then the precipitated DMAP-HCl salt was removed by filtration. The filtrate was concentrated under reduced pressure using a rotary evaporator. The crude material was purified by recrystallization (the crude material was dissolved in refluxing ether, allowed to cool to room temperature and slowly evaporated) or by column chromatography (silica gel, 2:1 methylene chloride/hexanes). The desired thiocarbonate 1 was obtained as white crystalline in 70% yield. Mp (DSC) 64.4° C. 1H-NMR (CDCl3, 300 MHz) δ 4.17 (s, 4H), 1.51-1.43 (q, 4H, J=7.5 Hz), 0.92-0.87 (t, 6H, J=7.5 Hz); 13C-NMR (CDCl3, 75 MHz) δ 189.53, 76.08, 33.67, 23.09, 6.97; IR (KBr pellet) (cm−1) 2960, 2920, 1455, 1395, 1380, 1290, 1240, 1200, 1180, 1060, 990, 930, 720.

Provenance & Evidence