1,2-Dithiolane-4-carboxylic acid, 4-methyl- synthesis

Yield: 75%

Reaction Conditions:

with sodium carbonate;potassium thioacetate in water;dimethyl sulfoxide at 100; for 22 h;

Steps:

9 Synthesis of compound A6
3,3-Dichloropivalic acid (4.00 g, 23.38 mmol) was added to a 3-neck round bottom flask and MilliQ water (20 ml_) was added. To the stirred suspension, sodium carbonate (2.28 g, 21 .52 mmol) was slowly added, followed by potassium thioacetate (5.34 g, 46.78 mmol). Then the resulting clear solution was heated to 100 °C, followed the addition of more sodium carbonate (7.44 g, 70.16 mmol). After 4 hours of refluxing at 100 °C, dimethyl sulfoxide (DMSO) (4 ml_) was added and left to stir for another 18 hours at 100 °C. The reaction mixture (pH ~ 9) was allowed to cool to room temperature and was acidified with hydrochloric acid (pH ~ 1 ) resulting in the formation of a yellow precipitate. The precipitate was filtered off and washed with ice-cold water 3 times before drying the yellow solid overnight in an vacuum oven. Yield: 2.93 g, 75%. ¹H-NMR (CDCIs, 400 MHz): 3.71 -3.68 (d, 2H), 2.97-2.94 (d, 2H), 1 .54 (s, 3H). ¹³C-NMR (CDC , 100 MHz): 181.37, 57.52, 47.72, 24.12.

References:

UNIVERSITEIT LEIDEN;KIELTYKA, Roxanne;KWAKERNAAK, Markus Cornelis;TONG, Ciqing;LIU, Tingxian WO2019/160419, 2019, A1 Location in patent:Page/Page column 39; 40; 43