Abstract
5'-Phosphoryl-N-benzoyldeoxyadenylyl-(3'-5')-N-anisoyl-3'-O-acetyldeoxycytidine (IVa) and 5'-phosphoryl-N-isobutyryldeoxyguanylyl-(3'-5')-N-anisoyl-3'-O-acetyldeoxy-cytidine (IVb) were synthesized by condensation of 5'-O-(N-trityl-p-aminophenyl) phosphoryl-N-benzoyldeoxyadenosine (Ia) or 5'-O-(N-trityl-p-aminophenyl) phosphoryl-N-isobutyryldeoxyguanosine (Ib) with N-anisoyldeoxycytidine 5'-phosphate using triisopropyl-benzenesulfonyl chloride (TPS). The intermediates (III) were isolated by extraction with organic solvents and the N-trityl-p-aminophenyl group was removed by oxidative hydrolysis. The dinucleotides (IV) were obtained without ion-exchange chromatography in yields of 50 to 60% and used for synthesis of the oligonucleotides. The tetranucleotide (VI) was synthesized by condensing V with IVa using TPS and was also isolated from the starting materials by the extraction method in a yield of 49%. The tetranucleotide (VI) was further condensed with the dinucleotides IVa and IVb to yield the hexanucleotide (VII) and the octanucleotide (VIII).
