A facile incorporation of the aldehyde function into DNA: 3-formylindole nucleoside as an aldehyde-containing universal nucleoside

The first facile incorporation of an aldehyde function into DNA without any protection/deprotection of the aldehyde was achieved by the use of 3-formylindole 2′-deoxynucleoside (1). This building block is very easily prepared and efficiently incorporated into oligonucleotides. In addition, 1 acted as a universal nucleoside in duplex. The post-synthetic modification of oligonucleotides bearing 1 with functionalized molecules was also effective.