Water → tert-butyl 4-((5R,7R)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

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Reaction Steps

Lithium hydroxide hydrate (0.779 mL, 28.0 mmol) was added to a solution of tert-butyl 4-((5R,7R)-7-(4-bromobenzoyloxy)-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (5.8 g, 11.2 mmol) in THF:H2O (150 mL, 2:1) at 0° C. The mixture was allowed to warm to room temperature and stirred at for 1 hour. The mixture was concentrated in vacuo, taken up into saturated sodium bicarbonate (100 mL) and extracted into EtOAc (2×200 mL). The reaction was dried over Na2SO4 and concentrated in vacuo to give tert-butyl 4-((5R,7R)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (3.8 g, 11.4 mmol, 100% yield) as a foam. Similarly, tert-butyl 4-((5R,7S)-7-(4-bromobenzoyloxy)-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate (1.29 g, 2.49 mmol) was dissolved in THF:H2O (10 mL, 2:1), cooled to 0° C. and then treated with solid lithium hydroxide hydrate. The solution was stirred at ambient temperature for 16 hours. The reaction was quenched with saturated NH4Cl and concentrated in vacuo. The resulting residue was diluted with ethyl acetate and a small amount of water. The layers were separated, and the aqueous layer was washed with ethyl acetate. The combined organic layers were washed with saturated NaHCO3 (2×), saturated NaCl, dried over Na2SO4 and concentrated in vacuo. The resulting residue was dried under high vacuum to give tert-butyl 4-((5R,7S)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate as a foam (0.843 g, 100%).

Provenance & Evidence