Diisopropyl vinylphosphonate

Scheme 3.2 Chain scission reaction of poly(diisopropyl vinylphosphonate).

Because the exploitation of the chemistry of unprotected phosphonylated acetaldehydes is handicapped by the sensitivity of the P-C bond in acidic media, a reliable alternative procedure for the preparation of dialkyl 1-chloro-1-formylmethylphosphonates from dialkyl 2-ethoxy-vinylphosphonates has been developed. Room-temperatme chlorination of 2-ethoxyvinylphosphonates with dry chlorine in CCI4 followed by hydrolysis of the phosphonylated a,p-dichloro ethers with water at 50-60°C gives the expected monochlorinated aldehydes in 73-82% yields (Scheme 5.70). A similar treatment with bromine in water at 0°C converts diisopropyl 2-ethoxyvinylphosphonate smoothly into diisopropyl 1-bromo-1-formylmethylphosphonate in 92% yield. ... 

The syntheses of carbocyclic analogs of phosphononucleosides (29) and (30a-c) have been reported. Phosphonic acid (29) was obtained by introduction of the benzoylated thymine on the 2(4-hydroxycyclopent-2-enyl)ethyl phosphonic acid diisopropyl ester under Mitsunobu conditions while (30a-c) were prepared by building-up the base around a phosphono-cyclopentylamine moi-ety. The vinylphosphonate derivatives of uridine, cytidine and cytosine ara-binoside (31a-c) have been prepared by Wittig condensation of [(diethoxyphos-phinyl)methylidene]triphenylphosphorane with the appropriately protected 5-aldehydic nucleoside derivatives. Dihydroxylation of the novel vinyl phosphon-ates offered the dihydroxylated phosphonate derivatives (32a-c). Each of these novel compounds was evaluated as substrates for the enzyme nucleotide monophosphate kinase, and their toxicity to K562 cells. All analogues were found to be poorly phosphorylated by the kinase and exhibited poor in vivo toxicity. ... 

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