Hydrochloric Acid → 2-Methyl-5-(2-nitro-4-[2-(3,4,5-trimethoxy-phenyl)-acetylamino]-phenyl)-furan-3-carboxylic acid

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Reaction Steps

Dissolve 2-Methyl-5-{2-nitro-4-[2-(3,4,5-trimethoxy-phenyl)-acetylamino]-phenyl}-furan-3-carboxylic acid methyl ester (41) (50 mg, 0.10 mmol) in THF (11.0 mL) and MeOH (0.5 mL) at rt and add 1M aqu LiOH (525 μL, 0.52 mmol). Stir the reaction mixture for 17 h at rt. Add dropwise 1M aqu. HCl (580 μL, 0.58 mmol) and extract the mixture with EtOAc (3 times), wash the combined organic layer with brine and dry it with Na2SO4. Purify the obtained crude product by preparative TLC (silica gel, EtOAc/MeOH 9+1) to obtain 2-Methyl-5-{2-nitro-4-[2-(3,4,5-trimethoxy-phenyl)-acetylamino]-phenyl}-furan-3-carboxylic acid (42) (35 mg, 71%) as a brown sticky solid. 1H NMR (400 MHz, CDCl3): 2.61 (s, 3H); 3.70 (s, 2H); 3.86 (s, 3H); 3.87 (s, 6H); 6.51 (s, 2H); 6.85 (s, 1H); 7.29 (br.s, 1H); 7.58 (d, 1H, J=8.6 Hz); 7.62 (dd, 1H, J1=9.0 Hz, J2=2.2 Hz); 7.98 (d, 1H, J=2.0 Hz).

Provenance & Evidence