Dichloromethane → {(3R,6R)-3-(2,3-dihydro-1H-inden-2-yl)-6-[(1S)-1-methylpropyl]-2,5-dioxo-1-piperazinyl}(2,6-dimethyl-3-pyridinyl)acetic acid hydrochloride

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Reaction Steps

2-{(3R,6R)-3-(2,3-dihydro-1H-inden-2-yl)-6-[(1S)-1-methylpropyl]-2,5-dioxo-1-piperazinyl}-2-(2,6-dimethyl-3-pyridinyl)-N-(2-hydroxyphenyl)acetamide (24.25 g, 45 mmol) (intermediate 2) and 1,1′-carbonyldiimidazole (11.7 g, 72 mmol) were dissolved in dry dichloromethane (200 ml) and left to stand under nitrogen for 20 hours. The solvent was removed in vacuo and the residue was dissolved in acetone (200 ml) and 2N hydrochloric acid (20 ml). After stirring for 20 hours the solvent was removed in vacuo and the residue was dissolved in methanol (50 ml). The solution was applied to an aminopropyl cartridge (2×70 g) and eluted with methanol (250 ml) and then 10% acetic acid in methanol (250 ml). The required fractions were combined and evaporated in vacuo. The residue was treated with 2N hydrochloric acid and the resulting solution evaporated in vacuo to give the title compound {(3R,6R)-3-(2,3-dihydro-1H-inden-2-yl)-6-[(1S)-1-methylpropyl]-2,5-dioxo-1-piperazinyl}(2,6-dimethyl-3-pyridinyl)acetic acid hydrochloride as a tan solid (12.21 g, 56%).

Provenance & Evidence