Sodium hydride → tert-butyl 4-cyano-3-hydroxy-2,2-dimethyl-2,5-dihydro-1H-pyrrole-1-carboxylate

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Reaction Conditions

Reaction Steps

45 g of methyl N-(tert-butoxycarbonyl)-N-(2-cyanoethyl)-2-methylalaninate were dissolved in dioxane (240 ml) under nitrogen and 7.9 g of sodium hydride were added. The mixture was refluxed for 6 hours (120° C. internal temperature), and then left to stand overnight at room temperature (TLC: CH2Cl2/EtOH 90/10). The solvent was evaporated, water was added (1000 ml) and the mixture was brought to pH 3-4 with citric acid. The aqueous layer was extracted 4 times with ethyl acetate, the extracts washed with a limited amount of water and evaporated. Then the residue was taken up with hexane, evaporated and crystallized from hexane. 33.1 g of tert-butyl 4-cyano-3-hydroxy-2,2-dimethyl-2,5-dihydro-1H-pyrrole-1-carboxylate were thus obtained (yield: 85%).

Provenance & Evidence