Diisopropylethylamine → (S)-N-(1-benzyloxycarbonyl-5-benzyloxycarbonyl-amino-pent-1-yl)-N-[2'-(1-triphenylmethyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-amine

Participants

Reaction Steps

5.0 g of (S)-2-amino-6-benzyloxycarbonylamino-hexanoic acid benzyl ester are dissolved in 250 ml of N,N-dimethylformamide. The solution is treated with 4.33 ml of N,N-diisopropyl-N-ethyl-amine, and the mixture is warmed to 80°, stirred for 30 minutes, treated with 4.44 g of 4-bromomethyl-2'-(1-triphenylmethyl-1H-tetrazol-5-yl)-biphenyl, stirred for 16 hours at 80° and then evaporated. The residue is worked up using water and ethyl acetate. The organic phase is dried and purified by means of flash-chromatography (200 g of silica gel; system N4). The (S)-N-(1-benzyloxycarbonyl-5-benzyloxycarbonyl-amino-pent-1-yl)-N-[2'-(1-triphenylmethyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-amine is obtained in the form of a brown oil [Rf : 0.18 (system N3)].

Provenance & Evidence