Sodium Hydroxide → 6-cyclopentyl-5-phenyl-4H-thieno[3,2-b]pyrrole-2-carboxylic acid

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Reaction Steps

A solution (0.015 M) of methyl 6-cyclopentyl-5-phenyl-4H-thieno[3,2-b]pyrrole-2-carboxylate in THF/MeOH (1:1) was treated with aqueous NaOH (2 N solution, 20 eq.) then the mixture was heated to reflux for 45 min. After cooling down, the mixture was concentrated then the residue diluted with water and acidified to pH 2-3 with aqueous HCl (1 N) and extracted with AcOEt. The combined organic phase was dried and concentrated to give a residue that was purified by RP-HPLC (Conditions: Waters X-TERRA MS C18, 10 micron, 19×150 mm; flow: 20 mL/min; Gradient: A: H2O+0.05% TFA; B: MeCN+0.05% TFA; 90% A isocratic for 2 min then linear to 10% A in 9 min) to afford the title compound (73%) as a solid.

Provenance & Evidence