Sulfuric Acid → HCID 10535400, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-ethoxy-4,5,6,7-tetrahydro-1,2-benzisoxazole 1a (35 g) in glacial acetic acid (500 mL) at 10° C. was added concentrated H2SO4 (29 mL). A solution of sodium dichromate (71 g) in glacial acetic acid (300 mL) kept at 40-45° C. was added dropwise during one hour at 20-25° C. The mixture was stirred for another 3 hours at 25-30° C. The reaction mixture was poured onto ice and diethyl ether (3 L). pH was adjusted to >10 by addition of concentrated aqueous NaOH. The organic phase was separated and worked up. The remaining crude title compound was purified by column chromatography on silica gel (eluted with ethyl acetate/heptane 1:1). Pure 3-ethoxy-4,5,6,7-tetrahydro-1,2-benzisoxazol-4-one was washed with diisopropyl ether and dried. Yield 27 g. Mp 98-99° C.

Provenance & Evidence