Phosphorylation of 2-(3-methyl-1,3-diazabuten-1-yl)-3-ethoxycarbonylthiophenes with phosphorus(III) halides

2-(3-Methyl-1,3-diazabuten-1-yl)-3-ethoxycarbonylthiophenes are phosphoryla ted with phosphorus(III) halides in basic media at position 5 of the thioph ene ring. Up to three heteroaromatic substituents can be introduced one by one at the same phosphorus atom. On this basis, mono-, bis-, and trishetary l substituted P(III) and P(V) derivatives have been obtained. Phosphorylate d 2-(N,N-dimethylformamidino)-3-ethoxycarbonylthiophenes provide a syntheti c access to phosphorylated thienopyrimidines. (C) 2001 John Wiley & Sons, I nc.