4-Piperidinone, 3,5-dibromo-2,2,6,6-tetramethyl-, hydrobromide (1:1) → 2,2,5,5-Tetramethyl-3-pyrroline-3-carboxylic Acid (5-Hydroxy-2,2-dimethyl-1,3-dioxepan-6-yl)-amide

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Reaction Steps

Analogously to Example 7, 78.79 g (200 mmol) of 3,5-dibromo-2,2,6,6-tetramethylpiperidin-4-one hydrobromide, 69.34 g of potassium tert-butylate, and 35.47 g (220 mmol) of 6-amino-2,2-dimethyl-1,3-dioxepan-5-ol are reacted in 800 ml of isopropanol and then extracted with dichloromethane. Yield: 37.66 g (60.3% of theory) of 2,2,5,5-tetramethyl-3-pyrroline-3-carboxylic acid (5-hydroxy-2,2-dimethyl-1,3-dioxepan-6-yl)amide which, crystallized from diethyl ether/hexane, shows a melting point of 125°-127° C.

Provenance & Evidence