Tetrahydrofuran → Methyl 2,4,5-triamino-3-fluorobenzoate

Participants

Reaction Steps

A mixture of methyl 2,4-diamino-3-fluoro-5-nitrobenzoate (5) (40.0 g, 173.7 mmol) and 5% Pd/C (3.0 g, Type 487; 0.4 mol % Pd relative to starting material), in methanol (300.0 mL) and tetrahydrofuran (300.0 mL) was stirred at 2000 RPM, under hydrogen (˜3.5 bar), at 50° C. in a 1.5 L hydrogenation vessel. After 6 hours the vessel was purged with nitrogen and HPLC analysis indicated that no starting material remained. The mixture was then filtered under nitrogen pressure and the filter washed through with THF (160 mL), to give a clear yellow solution. The solvent was removed by rotary evaporation, to provide methyl 2,4,5-triamino-3-fluorobenzoate (9) 37.5 g (93.3% w/w by NMR) as a solid, yield ˜100%. 1H NMR (400 MHz, d6 DMSO) δ 3.69 (3H, s, NMe), 4.20 (2H, br s, NH2), 5.24 (2H, br s, NH2), 5.70 (2H, br s, NH2), 6.83 (1H, d, J 1, Ar—H). 13C NMR (100 MHz, d6 DMSO) δ 51 (CH3), 98 (C, d, J 5), 110 (CH, d, J 2), 125 (C, d, J 6), 131 (C, d, J 12), 133 (C, d, J 12), 139 (CF, d, J 225), 166 (C═O). vmax/cm-1 3480, 3461, 3373, 3356, 3280, 3163, 1679, 1655, 1314. MS APCI (+) m/z 200 (M+1) detected.

Provenance & Evidence