Betamethasone Valerate → (2S)-2-((1,1-dimethylethoxycarbonyl)-amino)-3-methyl-butyric acid [11beta,21-dihydroxy-3,20-dioxo-9-fluoro-16beta-methyl-17-valeroyloxy-pregna-1,4-dien-21-yl] ester

Beteiligte Stoffe

Reaktionsschritte

21 mmol of betamethasone-17-valerate is reacted with 25 mmol of Boc-valine (Boc-Val-OH), 2.5 mmol of 4-dimethylaminopyridine and 27 mmol of dicyclohexylcarbodiimidazole in dichloromethane/dioxane 1:1 analogously to Example 1. Chromatography (1. ethyl acetate/hexane 2:1 and 2. ethyl acetate/hexane 1:1) yields 10.1 g (73%) of pure (2S)-2-((1,1-dimethylethoxycarbonyl)-amino)-3-methyl-butyric acid [11β,21-dihydroxy-3,20-dioxo-9-fluoro-16β-methyl-17-valeroyloxy-pregna -1,4-dien-21-yl] ester as foam.

Herkunft & Nachweise