N,N,N',N'-Tetramethylethylenediamine → HCID 14494148, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of the title compound of Example 1 (3.45 g, 10.0 mmol) and N,N,N',N'-tetramethylethylenediamine (0.75 mL, 5.0 mmol) in dry ether (70 ml) was cooled to 0° C. and treated with a solution of n-BuLi (2.5M) in hexane (8.0 mL, 20 mmol). The mixture was stirred at 0° C. for 0.25 hours and then at room temperature for an additional 3 hours. At this point the mixture was cooled to -78° C. A solution of 4,5-dihydro-6H-cyclopenta[b]thiophen-6-one (1.5 g, 10.8 mmol) in dry THF (15 ml) was then added dropwise and the resulting mixture was stirred at 78° to -60° C. over 1 hour. The reaction was quenched by addition of saturated NH4C1 solution and was allowed to warm to room temperature. The mixture was diluted with ether and H2O. The ether layer was separated and concentrated to leave an oil which was taken up in a mixture of 1N HCl (70 mL) and THF (105 mL). The resulting solution was stirred at room temperature overnight. The mixture was then diluted with H2O and extracted twice with ether. The extracts were set aside for later recovery of unreacted ketone while the aqueous layer was made basic by addition of solid NaOH and extracted twice again with ether. These extracts were combined, dried (Na2SO4) and concentrated in vacuo to leave a dark oil. This was placed under high vacuum and warmed at 50° C. for 1 hour to remove benzenemethanamine leaving 540 mg (23%) of the title compound. An NMR spectrum of this material showed it to be of sufficient purity to use directly in the next step. In other runs of this reaction, however, this material could be purified by flash chromatography on SiO2 using successively 1) CHCl3 and 2) 10% MeOH/CHCl3 as eluants.

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