Trifluoroacetic acid → HCID 66626031, compound

Participants

Reaction Steps

In a round bottom flask (50 mL), 2,5-diamino-thiophene-3,4-dicarboxylic acid diethyl ester (50 mg) was added to 20 mL isopropanol to which was added 2-thiophenecarboxaldehyde (24 mg) and a catalytic amount of trifluoroacetic acid (TFA). The mixture was refluxed for 20 hours. Complete removal of the solvent provides an orange solid which was purified by flash chromatography (SiO2), yielding the title compound as an orange solid (81%). M.p.: 114°-116° C. 1H-NMR (300 MHz, [D] acetone): δ=8.24 (s, 1H), 7.63 (d, 1H, 3J=5.0 Hz), 7.52 (dd, 1H, 3J=3.7 Hz and 4J=0.7 Hz), 7.48 (s, 2H), 7.14 (dd, 1H, 3J=5.0 Hz and 3.7 Hz), 4.32 (q, 2H, 3J=7.2 Hz), 4.19 (q, 2H, 3J=7.1 Hz), 1.37 (t, 3H, 3J=7.1 Hz), 1.26 (t, 3H, 3J=7.1 Hz). 13C-NMR (300 MHz, [D] acetone): δ=165.0, 164.3, 161.1, 161.0, 146.1, 143.2, 132.8, 132.1, 130.5, 128.4, 101.8, 61.0, 60.0, 14.3, 14.1.

Provenance & Evidence