Ammonium Hydroxide → (4S,6S)-4-(5-amino-2-fluorophenyl)-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-2-amine

Participants

Reaction Conditions

Reaction Steps

A sealable vial was charged with (4S,6S)-4-(5-bromo-2-fluorophenyl)-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-2-amine (4h, 585 mg, 1.647 mmol), sodium L-ascorbate (Acros; 32.6 mg, 0.165 mmol), sodium azide (Aldrich; 321 mg, 4.94 mmol), and copper(I) iodide (Aldrich; 94 mg, 0.494 mmol). The vial was evacuated and backfilled with Argon. EtOH (5.0 mL) and water (2.1 mL) were added, the reaction mixture purged with Argon, and then treated with N,N′-dimethyl-trans-1,2-cyclohexanediamine (Aldrich; 52.0 μL, 0.330 mmol). The reaction mixture was heated to 80° C. for 5 h and then stirred at ambient temperature for 16 h. A mixture of saturated aqueous NH4Cl and concentrated ammoniumhydroxide (5 mL; 9:1) was added, followed by EtOAc (10 mL). After 30 min, the reaction mixture was poured into a mixture of saturated aqueous NH4Cl/concentrated ammoniumhydroxide (50 mL; 9:1) and extracted with EtOAc (3×50 mL). The combined organic extracts were dried over Na2SO4 and concentrated to give a brown foam, which was dissolved in THF/water (8 mL; 3:1) and treated with trimethylphosphine (Aldrich; 1.0 M in THF) (2.0 mL, 2.000 mmol). The reaction mixture was stirred for 2 days and then concentrated under reduced pressure. The crude product was purified by flash chromatography on silica gel (Gradient: 0%→10% MeOH/CH2Cl2) to give (4S,6S)-4-(5-amino-2-fluorophenyl)-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-oxazin-2-amine (419 mg, 1.439 mmol) as a white foam. MS m/z=292.1 [M+H]+. Calculated for C12H13F4N3O: 291.2

Provenance & Evidence