反应详情

0.494 gm of tetronic acid (FW=100, 4.94 mmole) and 2.00 gm of ethyl-5-carboxy-2-thiophenecarboxaldehyde (FW=184, 10.9 mole) in 2mL of THF and 10 mL of concentrated HC1 was reacted as before by applying heat and efficient stirring. The total reaction time was 10 minutes. Workup and recrystallization from methanol gave 0.827 gm (63%) of the product. M. p. 204°-205.5° C. C12H10O4S: %C 564.13; %H 3.79; found %C 53.93; %H 4.00. NMR results: 1HNMR (d6DMSO (H2)/TMS δ1.39 (3H, t, 7HZ); 4.39 (2H, q, 7Hz); 7.83 (1H, d, 4Hz); 8.21 (2H, m).

1. temperatureby applying heat
2. customWorkup and recrystallization from methanol