Solid‐phase synthesis of oligodeoxynucleotides containing 4‐alkoxythymidine residues

Immobilized and fully protected oligodeoxynucleotides containing a 4-(1,2,4-triazolyl)-thymidine residue at a predetermined position were prepared according to a well-established phosphite triester methodology using 2-cyanoethyl phosphoramidites of a 4-(1,2,4-triazolyl)-substituted thymidine and standard protected nucleosides. Treatment of the immobilized oligomer with methanol, ethanol or n-propanol in the presence of DBU at 50°C gave the corresponding oligonucleotides containing 4-methoxy, 4-ethoxy- or 4-n-propoxythymidine residue.