4-Methylmorpholine → N-(N-(N-(N-((1,1-dimethyl)ethoxycarbonyl)-L-alanyl)-L-alanyl)-L-prolyl)-L-valine [9alpha-fluoro-11beta,21-dihydroxy-16beta-methyl-3,20-dioxo-17-valeroyloxy-pregna-1,4-dien-21-yl] ester

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Reaction Steps

1.04 g (1.50 mmol) of H-Val-O-BMV x TFA (Example 37), 500 mg (1.40 mmol) of Boc-Ala-Ala-Pro-OH and 168 mg (1.40 mmol) of Nhydroxybenzotriazole are dissolved in this sequence in 50 ml of dichloromethane, and 330 μl (3.00 mmol) of N-methylmorpholine is added. Then, a solution of 289 mg (1.40 mmol) of dicyclohexylcarbodiimide in 2 ml of dichloromethane is added and stirred for 20 hours at room temperature. Then, it is suctioned off from precipitated urea, the filtrate is concentrated by evaporation and filtered again. Chromatography of this amount of raw material (300 g of silica gel, hexane/acetone 1:1) yields 806 mg(63% ) of N-(N-(N-(N-((1,1-dimethyl)ethoxycarbonyl)-L-alanyl) -L-alanyl)-L-prolyl)-L-valine [9α-fluoro-11β,21-dihydroxy-16β-methyl-3,20-dioxo-17-valeroyloxy-pregna-1,4-dien-21-yl ] ester. Crystallization from dichloromethane/diisopropyl ether 542 mg (42%).

Provenance & Evidence