3-Chloro-5-nitrobenzotrifluoride synthesis

Yield:-

Reaction Conditions:

with hydrogenchloride;sulfuric acid;sodium nitrite in (2S)-N-methyl-1-phenylpropan-2-amine hydrate;ethanol

Steps:

3.1 Step 1
Step 1 56.7 ml of 96% sulphuric acid are added dropwise over 30 min to a brown solution of 90 g (374 mmol) of 4-amino-3-chloro-5-nitro-benzotrifluoride (Maybridge; Tintagel/England) in 500 ml of ethanol (exothermic). After heating to 75° C., 64.53 g (935 mmol) of sodium nitrite are added in portions over 1 h (gas evolution). Stirring is effected for 2.5 h at 75° C., followed by cooling to RT. The reaction mixture is poured onto 1.5 l of ice water and extracted 4 times with diethylether. Washing of the organic phase with 0.1 N HCl, sat. NaHCO₃ solution and brine, drying (Na₂SO₄) and concentrating by evaporation yield a brown oil. Column chromatography (SiO₂; hexane) yields 5-chloro-3-trifluoromethyl-nitrobenzene as an oil; ¹H-NMR (DMSO-d₆) δ8.62 (m, 1 H), 8.46 (m, 2H).

References:

Bold, Guido;Manley, Paul William US2003/158409, 2003, A1