N,N,N',N',N'',N''-Hexamethylmethanetriamine → 5-diethylcarbamoyl-4-((E)-2-dimethylamino-vinyl)-5-ethyl-2-oxo-2,5-dihydro-furan-3-carboxylic acid ethyl ester

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Reaction Steps

To a solution of 500.0 mg of compound (12) as obtained from example 5 (22.73 mmol) in 3.0 mL dimethyl formamide were added at room temperature 3.0 mL tris(dimethylamino)methane (17.3 mmol, 10.3 eq). The color of the reaction mixture changed from orange to brown and further to green. After 17 h, the mixture was diluted with 50 mL dichloromethane, washed with 25mL aqueous hydrochloric acid (1.0 M) and washed again three times with 50 mL brine. The organic phase was dried over 2 g sodium sulfate and was filtered. The filter cake was washed with 4 mL dichloromethane. After evaporation of the solvent in a rotary evaporator (50° C., 5 mbar), the crude product was obtained as an orange oil (627.0 mg, 106% by weight), which was liberated from residual dimethyl formamide in a high vacuum rotary evaporator (50° C., 0.5 mbar) yielding the title product (536.0 mg, 1.517 mmol, 90% by weight) as orange crystals.

Provenance & Evidence