A NEW METHOD FOR SYNTHESIS OF 4,4'-DIMETHOXYTRITYL CHLORIDE

The selection of appropriate protecting groups forms an essential part of oligonucleotide synthesis. 4,4'-Dimethoxytrityl group (DMT-), orig inally developed by Khorana et al.(1), is still the most frequently us ed acid labile protecting group for selective blocking of 5'-hydroxyl function of the sugar moiety in the nucleosides or nucleotides. The co nventional method of synthesis of 4,4'-dimethoxytrityl chloride (DMTCl , 7), involves the reaction of ethyl benzoate with anisyl magnesium br omide in dry benzene to give the crude product, di-p-anisylphenyl carb inol as a reddish oil which is subsequently converted into DMTCl on re fluxing with acetyl chloride.