Trifluoroacetic acid → HCID 12041753, compound

Participants

Reaction Steps

A solution of ethyl-7,8-diamino-chroman-2-carboxylate (927 mg, 3 mmol) in trifluoroacetic acid (20 mL) was heated to reflux for 6 hours and then concentrated in vacuo to give a residue. The residue was dissolved in ethyl acetate (100 mL) and then washed with saturated NaHCO3 solution (30 mL) and water (2×30 mL), dried over anhydrous Na2SO4. Purification by flash chromatography (30% CH2Cl2-hexanes) afforded 612 mg (65% yield) of the title compound as white solid: mp 134° C.; 1H NMR (400 MHz, CDCl3):[tautamer a]: δ:1.19 (t, J=7.1, 3H), 2.22 (m, 2H), 2.40 (m, 1H), 2.70 (m, 1H), 4.15 (q, J=7 Hz, 2H), 5.14 (m, 1H), 7.02 (d, J=8.0 Hz, 1H), 7.25 (d, J=8.0 Hz, 1H), 14.09 (bs, 1H). [tautamer b]: δ1.19 (t, J=7.1, 3H), 2.22 (m, 2H), 2.40 (m, 1H), 2.70 (m, 1H), 4.15 (q, J=7 Hz, 2H), 5.03 (m, 1H), 7.07 (s, 2H), 13.77 (bs, 1H); IR 3450, 3250, 2980, 2600, 1730, 1600, 1500, 1230 cm−1.

Provenance & Evidence