Methyl 7-nitro-2,3-dihydro-1,4-benzodioxine-5-carboxylate → Methyl 7-amino-2,3-dihydro-1,4-benzodioxine-5-carboxylate

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Reaction Steps

Methyl 7-nitro-2,3-dihydro-1,4-benzodioxine-5-carboxylate (5.6 g, 23.4 mmol) and palladium on carbon (250 mg, 30 wt. %) were suspended in ethyl acetate (200 mL). The reaction vessel was evacuated and then immediately filled with hydrogen gas. This deoxygenation process was repeated three times at atmospheric pressure. The black suspension was stirred under a hydrogen atmosphere for 18 h, at which time it was filtered through a bed of Celite and rinsed with ethyl acetate. The filtrate was concentrated, and the residue was triturated with diethyl ether to give 4.89 g (100%) of methyl 7-amino-2,3-dihydro-1,4-benzodioxine-5-carboxylate as an off-white powder: 1H NMR (400 MHz, CDCl3): 6.74 (d, J=2.8 Hz, 1H), 6.40 (d, J=2.8 Hz, 1H), 4.26-4.25 (m, 4H), 3.86 (s, 3H).

Provenance & Evidence