CLEAVAGE OF OLIGONUCLEOTIDES FROM SOLID-PHASE SUPPORTS USING O-NITROBENZYL PHOTOCHEMISTRY

Oligonucleotides are cleaved from modified solid phase supports using the o-nitrobenzylintramolecular photochemical redox reaction. Oligonucleotides can be cleaved before or after removal of protecting groups. Employment of phosphoramidites containing allyloxy protecting groups that are labile to Pd-O enables one to deprotect oligonucleotides without the use of base. The yields of isolated oligonucleotides relative to yields obtained using conventional hydrolytic cleavage vary between 59% and 87%. Tritium labeling indicates that small amounts of thymidine thymidine photodimers are formed during the photolysis time required to obtain good yields of oligonucleotides from the succinate linked photolabile support (4). Photodimer formation is minimized (<7%) during the prolonged irradiation required when cleaving oligonucleotides from 7 by employing bandpass filtering.