Sodium Hydroxide → 5-(4-chlorophenyl)-6-cyclohexyl-4H-thieno[3,2-b]pyrrole-2-carboxylic acid

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Reaction Steps

A solution (0.5 M) of methyl 4-(tert-butoxycarbonyl)-5-(4-chlorophenyl)-6-cyclohexyl-4H-thieno[3,2-b]pyrrole-2-carboxylate in DCM/TFA (1:1) was stirred at RT for 1 h. Evaporation of the solvent gave a solid that was dissolved in MeOH. The resulting solution (0.1N) was treated with aqueous NaOH (1 N solution, 12 eq.). The mixture was heated to reflux for 3 h then concentrated and acidified to pH 1 with aqueous HCl (1 N), the aqueous solution was diluted with MeCN and purified by RP-HPLC (Conditions: Waters X-TERRA MS C18, 5 micron, 19×150 mm; flow: 15 mL/min; Gradient: A: H2O+0.05% TFA; B: MeCN+0.05% TFA; 60% A isocratic for 2 min then linear to 0% A in 10 min) to afford the title compound (53%) as a solid.

Provenance & Evidence