Sulfuric Acid → Methyl 2-iodo-3-nitrobenzoate

反応式

[I:1][C:2]1[C:10]([N+:11]([O-:13])=[O:12])=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].S(=O)(=O)(O)O.[CH:19](OC)(OC)OC>CO>[CH3:19][O:5][C:4](=[O:6])[C:3]1[CH:7]=[CH:8][CH:9]=[C:10]([N+:11]([O-:13])=[O:12])[C:2]=1[I:1]

参加物

実験手順

2-iodo-3-nitro-benzoic acid (61 g, 208 mmol, prepared as described in Org. Syn. Coll. Vol. I, 56-58, and 125-127), sulfuric acid (40.8 g, 416 mmol), and trimethyl orthoformate (88.4 g, 833 mmol) were dissolved in 500 mL dry MeOH. The reaction was refluxed under argon for 20 h. The reaction mixture was concentrated to 100 mL then partitioned between saturated NaHCO3(aq) and CH2Cl2. The layers were separated and the aqueous layer extrated three times with CH2Cl2. The combined organic layers were dried (MgSO4) and concentrated in vacuo. The yellow solid was crystallized from CH2Cl2/hexanes yielding 2-iodo-3-nitro-benzoic acid methyl ester, 57.8 g (90%) as a yellow solid: m.p.64.0-64.5° C.; 1H NMR (300 MHz, CDCl3) δ 3.99 (s, 3H), 7.54 (app t, J=7.8 Hz, 1H), 7.70 (dd, J=8.1, 1.8 Hz, 1H), 7.77 (dd, J=7.8, 1.8 Hz, 1H).