N-ethyl-N,N-diisopropylamine in acetonitrile T=-15 - -10°C; 5 - 8 h;

N-ethyl-N,N-diisopropylamine in dichloromethane T=-35 - -30°C;

1: 4-nitrobenzyl (4R,5R,6S)-6-[(1R)-1-hydroxyethyl]-4-methyl-3,7-dioxo-1-azabicyclo[3.2.0]-heptane-2-carboxylate With N-ethyl-N,N-diisopropylamine; phosphorochloridic acid diphenyl ester in acetonitrile T=10 - 15°C; 5 h; 2: (2S,4S)-2-dimethylaminocarbonyl-4-mercapto-1-(4-nitrobenzyloxycarbonyl)pyrrolidine With N-ethyl-N,N-diisopropylamine in acetonitrile T=10 - 15°C; 5 - 8 h;