Diethyl squarate → HCID 10682488, compound

Participants

Reaction Steps

4-Amino-3-methylbenzonitrile (1.94 g, 14.7 mmol) was added to a solution of 3,4-diethoxy-3-cyclobutene-1,2-dione (2.53 g, 14.9 mmol) in acetonitrile (5 mL). After refluxing the mixture for 24 h a second portion of 3,4-diethoxy-3-cyclobutene-1,2-dione (1.15 g, 6.76 mmol) was added and heating was continued for an additional 48 h. The reaction mixture was diluted with ethyl acetate (50 mL), stirred vigorously and filtered free of undissolved solid. The filtrate was chromatographed (CH3OH/CH2Cl2) to afford 0.90 g (24%) of product as a yellow solid: 1H NMR (DMSO-d6): δ 10.50 (s, 1H), 7.76-7.63 (m, 2H), 7.31 (d, 1H), 4.71 (q, 2H), 2.33 (s, 3H), 1.38 (t, 3H).

Provenance & Evidence