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

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.

1. customThe thiocarbonate 1 was prepared by a variation of the thiocarbonylation procedure
2. customTo a three-necked round-bottomed flask, equipped with a mechanical stirrer and an additional funnel
3. temperatureThe mixture was cooled to 0-5° C.
4. customThis resulted in the formation of a bright orange DMAP-thiophosgene complex
5. additionAfter the completion of addition
6. stirringto stir for an hour at 0-5° C.
7. temperatureslowly warmed to room temperature
8. stirringto stir at room temperature for an additional hour
9. customthe precipitated DMAP-HCl salt was removed by filtration
10. concentrationThe filtrate was concentrated under reduced pressure
11. customa rotary evaporator
12. customThe crude material was purified by recrystallization (the crude material
13. dissolutionwas dissolved
14. temperaturein refluxing ether
15. temperatureto cool to room temperature
16. customslowly evaporated) or by column chromatography (silica gel, 2:1 methylene chloride/hexanes)

ORD record

ord-86a2f26b045b4d17949d7bd65c0410ae

Source dataset

uspto-grants-2003_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06653486B2