Multi-step reaction with 5 steps
1: 87 percent / 2 M aq. HBr / acetic acid
2: 1.) N-hydroxypyrrolidine-2,5-dione, DCC, 2.) NMM / 1.) THF, CH2Cl2, a) 0 deg C, 2 h, b) RT, overnight, 2.) THF, CH2Cl2, H2O, a) 0 deg C, 2 h, b) from 0 deg C to RT, 12 h
3: 50 percent / EEDQ / tetrahydrofuran; methanol
4: 74 percent / 2 M methanolic HCl / 40 h
5: 92 percent / Huenig's base / tetrahydrofuran; methanol / 2.5 h / 0 °C
With
4-methyl-morpholine; hydrogenchloride; 1-hydroxy-pyrrolidine-2,5-dione; hydrogen bromide; N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline; N-ethyl-N,N-diisopropylamine; dicyclohexyl-carbodiimide;
In
tetrahydrofuran; methanol; acetic acid;
DOI:10.1055/s-1996-4368