O-(Benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate → (S)-6-oxo-1,6-dihydro-pyridazine-4-carboxylic acid-{3-[2-fluoro-4-(4-methoxy-2-tri-fluoromethyl-phenylamino)-benzylcarbamoyl]-tetrahydrofuran-3-yl}-amide

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Reaction Steps

(S)-3-[(6-oxo-1,6-dihydro-pyridazine-4-carbonyl)-amino]-tetrahydrofuran-3-carboxylic acid (0.55 mmol) was dissolved in a mixture of 30 mL tetrahydrofuran, 4 mL DMF and 0.15 mL triethylamine, then TBTU (0.19 g, 0.58 mmol) was added and the mixture was stirred for 30 minutes at ambient temperature. Then 2-fluoro-4-(4-methoxy-2-trifluoromethyl-phenylamino)-benzylamine (0.17 g, 0.55 mMol, from 1b) was added and the mixture was stirred for a further two hours. As there was still some unreacted amine present, another 10 mg of the acid and 20 mg TBTU were added and the mixture was stirred further overnight. Then the solvents were evaporated off and the residue was chromatographed on silica gel (eluant: dichloromethane/methanol/ammonia: 95/5/0.5). In this way the product was obtained in a yield of 19% of theory.

Provenance & Evidence