Nitric Acid → (4aS,5S,7aS)-7a-(2-fluoro-5-nitrophenyl)-5-(trifluoromethyl)-4a,5,7,7a-tetrahydro-4H-furo[3,4-d][1,3]thiazin-2-amine

Participants

Reaction Conditions

Reaction Steps

N-((4aS,5S,7aS)-7a-(2-Fluorophenyl)-5-(trifluoromethyl)-4a,5,7,7a-tetrahydro-4H-furo[3,4-d][1,3]thiazin-2-yl)benzamide (5.15 g) was dissolved in TFA (75 mL), and the solution was cooled to 0° C. Sulfuric acid (conc., 20 mL) was added, followed by fuming nitric acid (2 mL) dropwise over 20 mins. After stirring at 0° C. for 90 mins, the reaction mixture was poured onto ice (200 g) and basified to pH 12 with 6N NaOH (aq.). After allowing the ice to melt, the mixture was extracted with EtOAc (3×500 mL), and the combined organic portions dried over MgSO4 and evaporated to afford the title compound (22.1 g, purity approx. 71%) which was used in the subsequent step without purification. 1H NMR (400 MHz, CDCl3) δ ppm 2.89 (d, J=3.8 Hz, 1H), 3.09 (br. s., 1 H), 3.28-3.54 (m, 1H), 3.80-4.03 (m, 1H), 4.50-4.70 (m, 3H), 4.71-4.86 (m, 1H), 7.21-7.30 (m, 1H), 8.18-8.28 (m, 1H), 8.45 (dd, J=6.8, 2.8 Hz, 1H)

Provenance & Evidence