Pyridine → 2-(4-Nitrobenzyl)-1,3,2-dioxaphosphinane 2-oxide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Oxalyl chloride (22.09 g) was added dropwise to a mixture of 4-nitrobenzylphosphonic acid (17.99 g), pyridine (13.76 g) and tetrahydrofuran (500 ml) at -78° C. After this mixture was stirred at -78° C. for 30 minutes and then at room temperature for 1.5 hours, the insoluble solid was filtered off. The filtrate was concentrated under reduced pressure; the residual oil was dissolved in tetrahydrofuran (500 ml). To this solution, a solution of 1,3-propanediol (2.58 g) in acetonitrile (30 ml) was added dropwise at -78° C. over a period of 15 minutes. Pyridine (5.62 g) was then added dropwise at the same temperature over a period of 5 minutes; the mixture was stirred at room temperature for 15 hours. After the insoluble substance was filtered off, the filtrate was concentrated under reduced pressure. The residue was subjected to silica gel column chromatography and eluted with ethyl acetate-chloroform-methanol (10:10:1, v/v) to yield 2-(4-nitrobenzyl)-1,3,2-dioxaphosphorinan-2-oxide (5.62 g, 26%), which was then recrystallized from ethanol-hexane to yield colorless needles having a melting point of 144°-145° C.

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