tert-Butoxy bis(dimethylamino)methane → tert-butyl 3-[(dimethylamino)methylene]-4-oxotetrahydro-1(2H)-pyridinecarboxylate

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Reaction Steps

To a solution of 4-oxo-piperidine-1-carboxylic acid tert-butyl ester (prepared according to the method of Example 101, Step A, 4.0 g, 20.0 mmol) in dimethylformamide (40 mL) was added tert-butoxybis(dimethylamino)methane (4.35 mL, 22 mmol). This mixture was stirred at reflux for 15 h, cooled to room temperature, diluted with water, and extracted with ethyl acetate (5×). The combined organic extracts were washed with water (3×) and brine (1×), dried over sodium sulfate, filtered, and evaporated to give 3.64 g (72%) of the title compound of Example 101, Step B as a brown oil that was sufficiently pure to carry on to the next step. 1H NMR (CDCl3, 400 MHz) δ7.47 (s, 1H), 4.53 (s, 2H), 3.58 (t, 2H), 3.09 (s, 6H), 2.43 (t, 2H), 1.46 (s, 9H); MS (APCI) 255 (MH+).

Provenance & Evidence