SYNTHESIS OF 9-(2-PHOSPHINOMETHOXYETHYL)ADENINE AND RELATED-COMPOUNDS

Alkyl 2-chloroethoxymethyl(diethoxymethyl)phosphinates VII and XIII were prepared by reaction of silyl esters of dialkoxymethylphosphinic acid with 2-chloroethyl chloromethyl ether. Adenine was alkylated with VII and XIII to give [2-(adenin-9-yl)ethoxyl]methyl(diethoxymethyl)phosphinates VIII and XIV, bearing the dialkoxymethyl protecting group on the phosphorus atom. Acid hydrolysis of compounds VIII and XIV afforded 9-(2-phosphinoethoxymethyl)adenine (X). Alkyl dialkoxymethylphosphinates V and XI reacted with paraformaldehyde to give hydroxymethylphosphinates XV and XIX which were converted into the synthons XVI, XVII and XVIII capable of introducing a protected hydroxymethylphosphino group on a hydroxy or amino group.