m-Chloroperbenzoic acid → 6-nitro-2,2,3-trimethyl-3,4-dihydro-3,4-epoxy-2H-1-benzopyran

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Reaction Steps

To a solution of 6-nitro-2,2,3-trimethyl-2H-1-benzopyran (10.0 g, 0.0457 mol) in dichloromethane (200 ml) at 0° C. was added m-chloroperbenzoic acid (13.5 g, 70%, 0.0548 mol). After stirring for eighteen hours at room temperature the mixture was washed successively with water, aqueous sodium hydrogen carbonate, water and then aqueous sodium hydroxide solution. The organic phase was separated and evaporated under reduced pressure to give 9.96 g (93%) of 6-nitro-2,2,3-trimethyl-3,4-dihydro-3,4-epoxy-2H-1-benzopyran, 1H NMR (CDCl3): δ 1.3 (s, 3H) , 1.55 (s, 3H) , 1.60 (s,3H), 3.8 (s,1H), 6.9 (d,1H), 8.15 (d,1H), 8.30 (s,1H).

Provenance & Evidence