[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]([CH:12](OCC)[O:13]CC)=[CH:8][C:9]=1[CH2:10][CH3:11])=[O:4].C(O)=O>O1CCOCC1>[CH3:1][O:2][C:3]([C:5]1[S:6][C:7]([CH:12]=[O:13])=[CH:8][C:9]=1[CH2:10][CH3:11])=[O:4]A solution of 5-Diethoxymethyl-3-ethyl-thiophene-2-carboxylic acid methyl ester (1.76 g, 6.46 mmol) in dioxane (16 ml) was cooled to 0° C. (ice bath). 88% formic acid (20 ml) was added in one portion and the mixture was stirred at 0° C. for 5 min and then at rt for 90 min. The reaction mixture was quenched by pouring into EtOAc. The organic layer was washed with water, dried over Na2SO4 and concentrated under reduced pressure to afford the desired product (1.22 g, 95% yield).
Wird geladen…