Lawesson's reagent → 4-(3-{2-[Tert-butoxycarbonyl-(3,4-difluoro-phenyl)-amino]-thioacetylamino}-4-methyl-benzyl)-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-(3-{2-[tert-butoxycarbonyl-(3,4-difluoro-phenyl)-amino]-acetylamino}-4-methyl-benzyl)-piperazine-1-carboxylic acid tert-butyl ester (160 mg) in toluene (4 ml) was added Lawesson's reagent (100 mg) and the reaction heated at 100° C. for 2.5 hr. After cooling to room temperature, the solvent was removed in vacuo to afford a yellow powder. Purification by NPHPLC (0-5% MeOH in CH2Cl2) afforded 4-(3-{2-[tert-butoxycarbonyl-(3,4-difluoro-phenyl)-amino]-thioacetylamino}-4-methyl-benzyl)-piperazine-1-carboxylic acid tert-butyl ester (120 mg). This was taken up in CH2Cl2 (1 ml) and trifluoroacetic acid (0.63 ml) added. After 2 hr stirring the reaction was poured into aqueous K2CO3 and the organic layer was separated, washed with aqueous K2CO3 and brine, dried (Na2SO4) and concentrated to leave yellow crystals. They were purified further by reverse phase HPLC to afford the title compound (14 mg).

Provenance & Evidence