Potassium Nitrate → 1-Methoxy-2-nitro-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-one

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Reaction Steps

To potassium nitrate in acetonitrile (50 mL) and trifluoroacetic anhydride (100 mL) at 0° C. was added dropwise 1-methoxy-5,7,8,9-tetrahydro-benzocyclohepten-6-one (25 g, 0.131 mol) in 50 mL acetonitrile. The reaction was stirred for 2.5 hours while warming to RT. The reaction was concentrated without heat on a rotary evaporator. MeOH was added and stirred briefly. Reconcentrated and worked-up by partitioning between dichloromethane and sat. sq. sodium bicarbonate solution. The organic layer was separated and dried (Mg2SO4), concentrated and purified by chromatography ISCO (330 g silica cartridge: gradient elution—10 to 50% EA:HEX over 60 minutes) affording two isomers. The title compound was the later eluting (10.7 grams, 34.6% yield). 1H-NMR (400 MHz, CDCl3) 7.70 (d, J=8.3 Hz, 1H), 7.06 (d, J=8.3 Hz, 1H), 3.92 (s, 3H), 3.80 (s, 2H), 3.13-3.09 (m, 2H), 2.60 (t, J=7.0 Hz, 2H), 2.10-2.03 (m, 2H).

Provenance & Evidence