Sodium Hydroxide → HCID 136151230, compound

Participants

Reaction Steps

0.53 g (1.38 mmol) of ethyl 1-(1-ethoxyethyl)-3-(1H-indol-2-yl)-1H-thieno[2,3-c]pyrazole-5-carboxylate is dissolved with stirring in 40 cm3 of ethanol at a temperature in the region of 20° C. 2.8 cm3 (2.8 mmol) of 1N sodium hydroxide solution are then run in, and the resulting solution is then refluxed for 2 hours. The reaction medium is then concentrated to dryness under reduced pressure (2.7 kPa) and the residue is taken up in 30 cm3 of water to which is added 0.17 g of citric acid. The mixture is extracted with twice 50 cm3 of dichloromethane, and acidification of the aqueous phase is continued by addition of citric acid down to pH 2, and the extraction is then continued with twice 50 cm3 of dichloromethane. The various organic phases are combined, dried and then evaporated to dryness under reduced pressure (2.7 kPa). 0.46 g of 1-(1-ethoxyethyl)-3-(1H-indol-2-yl)-1H-thieno[2,3-c]pyrazole-5-carboxylic acid is thus obtained in the form of a yellow solid melting at 204° C.

Provenance & Evidence