ethyl 2-aMino-4-(2-ethoxy-2-oxoethyl)thiazole-5-carboxylate synthesis

Yield:-

Reaction Conditions:

Stage #1: diethyl 1,3-acetonedicarboxylatewith thionyl chloride at 0 - 50; for 1.5 h;
Stage #2: thiourea in ethanol; for 0.5 h;Reflux;

Steps:

31.A

To a neat diethyl 3-oxopentanedioate (20.2 g, 0.10 mol) was added sulfurous dichloride (13.5 g, 0.11 mol) dropwise at 0°C, the mixture was then stirred at rt for lh followed by heated at 50°C for 0.5 h. The resulting solution was added dropwise to a solution of thiourea (7.6 g, 1.0 mol) in EtOH (50 mL). The mixture was reflux for 0.5 h and added into ice water then alkaline with aq. Na₂C03, the precipitate was filtered off and dried to afford the title compound (16 g, 62%). 1H NMR (400 MHz, CDC1₃) δ 6.01 (brs, 2H), 4.27 (q, J= 7.2 Hz, 2H), 4.17 (q, J = 7.2 Hz, 2H), 4.03 (s, 2H), 1.34 (t, J = 7.2 Hz, 3H), 1.26 (t, J = 7.2 Hz, 3H).

References:

WO2012/59041,2012,A1 Location in patent:Page/Page column 68; 69