Water → Carbonic acid 8-dimethylamino-1-methyl-2-oxo-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-4-yl ester ethyl ester

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Reaction Steps

105 mg 8-Dimethylamino-1-methyl-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]decane-2,4-dione (from Step 4) and 62 mg triethylamine are dissolved in 5 ml tetrahydrofuran, and the mixture cooled in an ice bath. Then, 40 mg ethyl chloroformate is added at 0° C. The mixture is allowed to warm to room temperature, and stirred for 2 hours. Then water is added and the mixture extracted with ethyl acetate. The organic layer is washed with brine, dried over sodium sulfate, and the solvent evaporated. The crude product is purified by chromatography on silica gel, with acetone as a solvent, yielding 110 mg Carbonic acid 8-dimethylamino-1-methyl-2-oxo-3-(2,4,6-trimethyl-phenyl)-1,8-diaza-spiro[4.5]dec-3-en-4-yl ester ethyl ester as an oil. 1H-NMR (CDCl3): 6.85 ppm (s, 2H), 4.03 ppm (q, 2H), 3.00 ppm (m, 2H), 2.96 ppm (s, 3H), 2.85 ppm (m, 2H), 2.42 ppm (s, 6H), 2.27 ppm (m, 2H), 2.24 ppm (s, 3H), 2.16 ppm (s, 2H), 1.83 ppm (m, 2H), 1.09 ppm (t, 3H).

Provenance & Evidence