Sodium Bicarbonate → HCID 178498675, compound

Participants

Reaction Steps

The refrigerated solution of 4-(3,4-diamino-5-chloro-benzenesulfonyl)-5-methylsulfanyl-thiophene-2-carboxylic acid methyl ester ((from above step b) 0.224 g, 0.570 mmol) in formic acid (4.5 mL) from above was allowed to slowly warm to room temperature and then heated to reflux (110° C.) 3 h. The mixture was cooled to room temperature and poured over ice. The pH was adjusted to pH 8 by carefully adding solid NaHCO3 portionwise with stirring. The aqueous solution was extracted with EtOAc (2×150 mL). The combined organic layers were washed with brine and dried over Na2SO4. The solvent was removed in vacuo to afford the product 4-(7-chloro-1H-benzoimidazole-5-sulfonyl)-5-methylsulfanyl-thiophene-2-carboxylic acid methyl ester (0.201 g, 87%) as a brown foamy solid. The crude material was used directly in the next reaction.

Provenance & Evidence