N,N,N',N'-Tetramethylethylenediamine → [5-(1,3-Dimethyl-imidazolidin-2-yl)-thiophen-2-yl]-phosphonic acid diethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 1,3-Dimethyl-2-thiophen-2-yl-imidazolidine (10 g, 60.17 mmol) in THF was added TMEDA (9.1 ml, 60.17 mmol), cooled to −78° C., then added 1.6 M nBuLi (47 ml, 75.21 mmol). After stirring at −78° C. for 30 min the mixture was warmed up to 0° C. in 1 hr and treated with diethyl chlorophosphonate (10.4 ml, 72.2 mmol). The reaction mixture was stirred at 0° C. for another 30 min. The reaction was then quenched by adding EtOAc and water. The EtOAc layer was separated and the water layer was further extracted with EOAc once. The combined EtOAc layers were dried over MgSO4, filtrated and concentrated to afford the crude product [5-(1,3-dimethyl-imidazolidin-2-yl)-thiophen-2-yl]-phosphonic acid diethyl ester (17 g). 1H NMR (300 MHz, DMSO-d6): δ 7.44 (m, 1H), 7.24 (m, 1H). 4.01 (m, 4H), 3.18 (m, 2H), 2.53 (m, 2H), 1.22 (m, 9H).

Provenance & Evidence