Thiodiglycol → 5-Hydroxy-3-thiapentyl N,N,N',N'-tetrakis(2-chloroethyl)phosphorodiamidate

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Reaction Conditions

Reaction Steps

N,N,N′,N′-Tetrakis(2-chloroethyl)phosphorodiamidoyl chloride, 636 mg (1.745 mmol), and bis(2-hydroxyethyl)sulfide, 1 mL (9.67 mmol), were dissolved in 8 mL anhydrous tetrahydrofuran and cooled to 0-5° C. in an ice-water bath. Potassium tert-butoxide, 1.8 mL of 1 M solution in tetrahydrofuran (1.8 mmol), was added over a 10 minute period, and the reaction mixture kept at 0-5° C. for another 30 minutes. The reaction mixture was allowed to warm to room temperature and stirred at room temperature for 18 hours. It was then diluted with ethyl acetate; and the ethyl acetate layer separated, washed with 1 M hydrochloric acid and brine, then dried over anhydrous magnesium sulfate, and the ethyl acetate removed under vacuum. The crude 5-hydroxy-3-thiapentyl N,N,N′,N′-tetrakis(2-chloroethyl)phosphorodiamidate was purified by column chromatography (silica gel, eluting with 25% ethyl acetate/hexane and 100% ethyl acetate), and obtained as a colorless oil, 335 mg (42.6% yield), identified by HPLC and 1H and 31P NMR.

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