triethylamine; tetra-(n-butyl)ammonium iodide in tetrahydrofuran T=10 - 20°C; 4 h;

1: With methanol; potassium carbonate T=20°C; 5 - 7 h; 2: With hydrogenchloride in water T=20°C; pH=1.5 - 2.0; Product distribution / selectivity;

methanol; potassium carbonate T=20°C; 1 - 5 h; Product distribution / selectivity;

1: 17β-((N,N-dimethyl-carbamyl)-thio)formoxyl-6α,9α-difluoro-11β-hydroxyl-16α-methyl-17α-propionyloxy-3-oxoandrosta-1,4-diene With sodium hydrogensulfide in isobutyramide T=0 - 20°C; 4 h; 2: fluoromethyl bromide in isobutyramide T=-5°C; 1 h; 3: With dihydrogen peroxide in isobutyramide; water T=20°C; 0.5 h; Product distribution / selectivity;

1: Et2NH / Heating 2: 67.1 percent / KHCO3 / dimethylformamide / 0.25 h / 22 - 25 °C View Scheme