Nucleotides -: Part LVII -: Synthesis of phosphoramidite building blocks of 2′-amino-2′-deoxyribonucleosides:: New compounds for oligonucleotide synthesis

The chemical synthesis of 2'-amino-2'-deoxyribonucleosides of uracil, cytosine, adenine, and guanine, and their conversion into suitably protected 3'-phosphoramidite building blocks 35-40 for oligonucleotide synthesis are described. The aglycone and the 2'-amino functions were protected using the 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) group. The synthesis of the 3'-O-succinyl (3'-0-(3-carboxypropanoyl))-substituted starting nucleoside 41 is described and its behavior examined in solution and on solid phase with regard to an anticipated migration during 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) deprotection. Oligonucleotides were prepared using the new building blocks, and their hybridization properties were studied by UV-melting techniques.