Ethyl 2-thiopheneglyoxylate → [(3-Methyl-butyl)-hydrazono]-thiophen-2-yl-acetic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of oxo-thiophen-2-yl-acetic acid ethyl ester (1d) (3.97 g, 21.6 mmol) in absolute ethanol (100 mL), (3-Methyl-butyl)-hydrazine (2b) (2.0 g, 19.6 mmol) was added. The mixture was stirred at 80° C. under N2 atmosphere for 2-25 hours. The reaction mixture was concentrated under reduced pressure and the residue was purified by flash chromatography on silica gel to give the desired product (3d) (2.48 g) that was directly used in the next step. LC-MS (ESI+): m/e 269.2 [M+1]+, 537.4 [2M+1]+, 559.0 [2M+Na]+ (exact ms: 268.12).

Provenance & Evidence