2-Thiophenecarboxylic acid → N-[2-chloro-4-[[(2,3-dihydro-1H-indol-4-ylmethyl)amino]carbonyl]benzoyl]-3-(thiophene-2-carbonyl)amino-L-alanine

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Reaction Steps

To 3-amino-N-[2-chloro-4-[[(1H-indol-4-ylmethyl)amino]carbonyl]benzoyl]-L-alanine on Wang resin (Example 69; 100 mg) was added a solution of HOAT (70 mg, 0.51 mmol), diisopropylcarbodiimide (80 μL, 0.51 mmol), and thiophene-2-carboxylic acid (70 mg, 0.55 mmol) in 1-methyl-2-pyrrolidinone (1 mL). The mixture was agitated for 2 h and then the resin was filtered and washed extensively with dichloromethane and methanol. Cleavage of the product was effected with triethylsilane/trifluoroacetic acid/dichloromethane (2:1:1; 1 mL) at room temperature for 30 min. The solvent was evaporated and the residue was purified by HPLC to give 3-(thiophene-2-carbonyl)amino-N-[2-chloro-4-[[(2,3-dihydro-1H-indol-4-ylmethyl)amino]carbonyl]benzoyl]-L-alanine (10.7 mg).

Provenance & Evidence