Glyoxylic Acid → 5-bromo-3,4-dihydro-1H-isochromene-1-carboxylic acid

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Reaction Steps

A solution of 2-(2-bromophenyl)ethanol (40 g, 0.2 mol) and glyoxylic acid (16 g, 0.22 mol) in 100 mL of trifluoacetic acid was refluxed overnight. The solvent was concentrated. Water and ammonium hydroxide was added to the residue to adjust the pH of the solution over 7. The solution was extracted with diethyl ether, and the aqueous layer was adjusted to about 3 with 1M HCl, and then the solution was extracted with ethyl acetate. The organic layer was dried and evaporated. The residue was without purification to give 5-bromo-3,4-dihydro-1H-isochromene-1-carboxylic acid. 1H-NMR (400 MHz, CDCl3) δ 7.52 (d, J=7.6 Hz, 1H), 7.12 (t, J=7.8 Hz, 2 H), 5.33 (s, 1H), 4.27˜4.33 (m, 1H), 3.99˜4.06 (m, 1H), 2.87˜2.89 (m, 2H).

Provenance & Evidence