NUCLEOTIDES PART: LXXVII NEW TYPES OF FLUORESCENCE LABELING OF 2'-DEOXYGUANOSINE

摘要

Protected 3',5'-diacetyl- (5) and 3',5'-O-(tetraisopropyldisiloxan-1,3-diyl)-2'-deoxyguanosine (6) have been labeled with 5-aminofluorescein (9) to form 10 and 11 which reacted under Mitsunobu conditions with 2-(4-nitrophenyl)ethanol to 13 and 14, respectively. 14 could also been synthesized directly from 6 with 15 in one step. Selective desililation with fluoride ion led from 1 to 12 and from 14 to 16. Dimethoxytritylation of 16 gave 18 which was further converted into the building blocks 19-21. The synthesis of the 2'-deoxyguanosylyl[3'→ 5']-2'-deoxy-N2-{[(fluorescein-5-yl)amino]carbonyl}guano-sylyl[3'→ 5']-2'-deoxyguanosine trimer (28) was achieved by step-wise built-up from 20 with 22 to 23 and followed by coupling of 24 with 26 yielding 27. Due to the unified blocking group pattern in 27 fully deprotection afforded afforded only one step by treatment with DBU to give 28. Several oligo-2'-deoxynucleotides containing fluorescein labeled 2'-deoxyguanosines at various positions of the chain were formed in a DNA-synthesizer and their fluorescence properties and the T_m s of the corresponding duplexes measured.