Sodium Hydroxide → 5-Difluoromethyl-5-(2-fluoro-6-nitro-phenyl)-5,6-dihydro-2H-[1,4]oxazin-3-ylamine

Participants

Reaction Steps

Potassium nitrate (60.3 g, 596 mmol) was added portionwise to 600 ml sulfuric acid (Temperature<20° C.). This solution was added dropwise to a solution of 5-difluoromethyl-5-(2-fluoro-phenyl)-5,6-dihydro-2H-[1,4]oxazin-3-ylamine (112 g, 459 mmol) in 600 ml sulfuric acid, while keeping the reaction temperature<22° C. with an ice bath. After stirring for 1 h, the mixture was poured onto 10 Kg ice. TBME (6 L) was added and the pH was adjusted to 12-14 by the addition of about 5 L 30% aqueous NaOH. The phases were separated and the aqueous phase was extracted twice with TBME. The combined organic layers were dried with sodium sulfate and evaporated to give 130 g of a yellow solid that was used further without purification.

Provenance & Evidence