Dimethyl 4-hydroxy-3-nitrophthalate → Dimethyl 4-hydroxy-5-nitrophthalate

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Reaction Steps

A mixture of dimethyl 4-hydroxyphthalate (25.0 g, 0.119 mol) and concentrated sulfuric acid at 0°-5° C., is treated dropwise with nitric acid (90%, 6.10 mL, 0.142 mo)), stirred for 10 minutes, poured into ice water and extracted with ethyl acetate. The combined organic extracts are dried (MgSO4) and concentrated in vacuo to give the title product mixture as a viscous yellow oil, 29.7 g (98.0%), identified by NMR spectral analysis. Flash chromatography (silical gel, 2% ethyl acetate/methylene chloride) of the mixture gives dimethyl 4-hydroxy-5-nitrophthalate as a yellow solid 3.70 g, mp 82°-85° C. and dimethyl 3-nitro-4-hydroxyphthalate as a pale yellow solid, 3.80 g, mp 108°-111° C.

Provenance & Evidence