2-Ethoxy-1-(ethoxycarbonyl)-1,2-dihydroquinoline → (2S,4S)-4-acetylthio-1-(4-nitrobenzyloxycarbonyl)-2-(3-allyloxycarbonylphenylcarbamoyl)pyrrolidine

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Reaction Steps

The above allyl 3-aminobenzoate (26.6 g, 0.15M) was condensed with 4-acetylthio-1-(4-nitrobenzyloxycarbonyl)-2-carboxypyrrolidine (55.2 g, 0.15M) by suspension in toluene (750 ml) and addition of EEDQ (44.5 g, 0.18M). The mixture was stirred overnight, diluted with EtOAc (2 l) and washed with dilute HCl, water and brine. The EtOAc phase was dried and evaporated, and the residue recrystallised from ethanol giving (2S,4S)-4-acetylthio-1-(4-nitrobenzyloxycarbonyl)-2-(3-allyloxycarbonylphenylcarbamoyl)pyrrolidine (67.7 g). Nmr (DHSO-d6): δ 1.93 (quintet, 1H); 2.9 (m, 1H); 3.35 (m, 1H); 3.91-4.14 (m, 2H); 4.49 (quintet, 1H); 4.81 (dd, 2H); 5.22 (dd, 2H); 5.2-5.44 (m, 2H); 5.95-6.10 (m, 1H); 7.47 (d, 2H); 7.66 (t, 2H); 7.8-7.93 (m, 2H); 8.18-8.3 (m, 2H); 10.31 (s, 1H).

Provenance & Evidence