5-Methoxy-2-thiopheneglyoxylic acid ethyl ester → 5-Methoxy-2-thiopheneglyoxylic acid

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Reaction Steps

The latter ester (25 g) is stirred in 500 ml of 5% aqueous KOH in methanol (250 ml H2O, 250 ml CH3OH, 25 g KOH) at room temperature for about 2 hr. The mixture is diluted with water and extracted several times with ether to remove all neutral material. The aqueous fraction is cooled with crushed ice, acidified with 10% HCl and extracted with ether. The ether extract is washed with water and brine, dried (MgSO4) and concentrated to give 5-methoxy-2-thiopheneglyoxylic acid (3; X1 = CH3O, X2 and X3 = H and R10 = H); γmaxCHCl3 3000, 1630, 1625, 1530 cm -1.

Provenance & Evidence