Cyanamide → 3-(N-cyano-S-methylsulfonimidoyl)-2-methoxy-4-(trifluormethyl)benzoic acid

Beteiligte Stoffe

Reaktionsschritte

3.71 g (33.1 mmol) of potassium tert-butoxide were added to a solution of 4.00 g (15.0 mmol) of 2-methoxy-3-(methylsulfanyl)-4-(trifluoromethyl)benzoic acid in 250 ml of methanol. The mixture was stirred for 10 minutes, and 1.07 g (25.5 mmol) of cyanamide and 4.81 g (27.0 mmol) of N-bromsuccinimide were then added in succession. The contents was then stirred at RT for 2 h. The mixture was then freed from the solvent on a rotary evaporator and the residue was taken up in a mixture of in each case 120 ml of acetonitrile and water. 7.21 g (45.1 mmol) of sodium permanganate monohydrate were added, and the mixture was stirred at RT for one week. During this week, both after one day and after a further day, in each case 3.6 g (22.5 mmol) of sodium permanganate monohydrate were added. For work-up, a 10% by weight strength solution of sodium bisulfate was added. On a rotary evaporator, at a temperature of at most 30° C., the solvent was substantially removed. The residue was cooled in an ice bath and then acidified with 1 M hydrochloric acid. The mixture was extracted three times with ice-cold dichloromethane. The combined organic phases were freed from the solvent on a rotary evaporator and the residue was purified chromatographically, which gave 1.30 g of product of a purity of 80% by weight.

Herkunft & Nachweise