Boron tribromide → 5-(4-Chlorophenyl)-6-cyclohexyl-4-(2-morpholin-4-yl-2-oxoethyl)-4H-thieno[3,2-b]pyrrole-2-carboxylic acid

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Reaction Steps

A solution (0.1 M) of methyl 5-(4-chlorophenyl)-6-cyclohexyl-4-(2-morpholin-4-yl-2-oxoethyl)-4H-thieno[3,2-b]pyrrole-2-carboxylate was treated with BBr3 (4 eq.) and the mixture was stirred at RT. After 1 h an additional quantity of BBr3 (2 eq.) was added and the mixture was stirred at RT for 1 h, then quenched with aqueous HCl (1 N) and extracted with AcOEt. The combined organic phase was dried and solvent was evaporated under reduced pressure to give a residue which 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 (47%) as a solid.

Provenance & Evidence