N,N,N',N'-Tetrakis(2-chloroethyl)phosphorodiamidic Chloride → Di[2-[[bis[bis(2-chloroethyl)amino]phosphinyl]oxy]ethyl]sulfide

Participants

Reaction Conditions

Reaction Steps

5-Hydroxy-3-thiapentyl N,N,N′,N′-tetrakis(2-chloroethyl)phosphorodiamidate, 174 mg (0.387 mmol), and N,N,N′,N′-tetrakis(2-chloroethyl)phosphorodiamidoyl chloride, 363 mg (0.996 mmol), were dissolved in 15 mL anhydrous tetrahydrofuran and cooled to 0-5° C. in an ice-water bath. Potassium tert-butoxide, 0.4 mL of 1 M solution in tetrahydrofuran (0.4 mmol), was added over a 10-15 minute period, and the reaction mixture kept at 0-5° C. for another 30 minutes under nitrogen. The reaction mixture was allowed to warm to room temperature and stirred at room temperature for 43 hours. Additional potassium tert-butoxide and N,N,N′,N′-tetrakis(2-chloroethyl)phosphorodiamidoyl chloride were added over the next 4 days to drive the reaction to completion. After 4.5 days, the reaction mixture was diluted with ethyl acetate; and the ethyl acetate layer separated, washed with water and brine, then dried over anhydrous magnesium sulfate, and the ethyl acetate removed under vacuum. The crude di[2-[[bis[bis(2-chloroethyl)amino]phosphinyl]oxy]ethyl]sulfide, 630 mg, was twice purified by preparative HPLC, and the product fractions combined and lyophilized, giving di[2-[[bis[bis(2-chloroethyl)amino]phosphinyl]oxy]ethyl]sulfide, compound 1CC, as a colorless oil, compound 1CC, 56 mg (18% yield), identified by HPLC and 1H and 31P NMR. Mass spectrum: 779 (C20H40Cl8N4O4P2S+4+H+).

Provenance & Evidence