N,N-Diphenylcarbamic chloride → N-(N-(N-(N-(diphenylcarbamoyl)-L-alanyl)-L-alanyl)-L-prolyl)-L-valine [11beta,21-dihydroxy-3,20-dioxo-6alpha-methyl-17-propionyloxy-pregna-1,4-dien-21-yl] ester

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Reaction Steps

150 mg (0.17 mmol) of H-Ala-Ala-Pro-Val-O-MPP x TFA (Example 3) and 150 μl (0.89 mmol) of diisopropylethylamine are dissolved in 6 ml of dichloromethane, mixed with 155 mg (0.37 mmol) of diphenylcarbamoyl chloride and stirred for 110 hours at room temperature. The residue that remains after removal of the solvent i.vac. is chromatographed. Gradient chromatography (Lichroprep Si60A pre-packed column, hexane→hexane/dichloromethane/methanol 30:60:10) yields 158 mg (97%) of N-(N -(N-(N-(diphenylcarbamoyl)-L-alanyl)-L-alanyl)-L-prolyl)-L-valine [11β,21-dihydroxy-3,20-dioxo-6α-methyl-17-propionyloxy-pregna -1,4-dien-21-yl] ester, and after recrystallization, 112 mg (68%) in crystalline form from dichloromethane/diisopropyl ether.

Provenance & Evidence