Sodium Hydroxide → 3-Methyl-1,6-diazaspiro[3,5]nonane-1-carboxylic acid 1-benzyl ester

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Reaction Steps

To a solution of an optically-active compound of 3-methyl-1,6-diazaspiro[3,5]nonane-1,6-dicarboxylic acid 1-benzyl ester 6-tert-butyl ester (5.54 g) in chloroform (83 ml) cooled to 4° C. was added a solution of trifluoroacetic acid/chloroform (28 ml/55 ml), and the mixture was warmed to room temperature and stirred for additional 2 hours. The reaction mixture was cooled to 4° C., and thereto was added 4M aqueous sodium hydroxide solution (90 ml). The mixture was basified to be pH 9 to 10, and extracted with chloroform/methanol (4/1, 60 ml×2) twice. The combined organic layer was sequentially washed with 5% aqueous sodium bicarbonate solution, 10% aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluent: chloroform/methanol/28% ammonia water=90/10/1) to give the titled compound (2.20 g).

Provenance & Evidence