Synthesis and photophysical evaluation of new fluorescent 7-arylethynyl-7-deazaadenosine analogs

Abstract

Three new fluorescent 7-deaza-2′-deoxyadenosine analogs were synthesized via the Sonogashira cross-coupling reaction of 7-iodo-7-deaza-2′-deoxyadenosine with 1-ethynylpyrene, 2-ethynyl-6-methoxynaphthalene, and 9-ethynylphenanthrene. The spectral properties of these analogs were evaluated in dioxane, EtOH, and H2O to determine their potential for use as environmentally sensitive fluorescent probes. All three analogs displayed large solvatofluorochromicity in H2O, relative to their emission wavelengths in dioxane or EtOH. Moreover, all three analogs exhibited microenvironmental sensitivity of their fluorescence emission intensity, being moderate to high quantum yields in dioxane and EtOH and significantly lower in H2O. Various attempts to perform domino cross-coupling and annuation reactions on 7-deaza-7-alkynyladenine derivatives to form a new fused tricyclic adenine analog were unsuccessful.

The selection of a hydrophobic 7-phenylbutyl-7-deazaadenine-modified DNA aptamer with high binding affinity for the Heat Shock Protein 70

“…For the selection and synthesis of aptamers, we needed the modified nucleoside triphosphate (for enzymatic synthesis) as well as the corresponding nucleoside phosphoramidite (for chemical synthesis). The synthesis started with the preparation of 7-iodo-2ʹ-deoxy-7-deazaadenosine (1, dA I ) by the modified reported procedure 37 where the changes in protocol resulted in overall higher yields (Supplementary Information, section 1.2). dA I was further used in Pd-catalysed Sonogashira cross-coupling with but-3-yn-1ylbenzene in presence of TPPTS, CuI and TEA which resulted in the alkyne-linked modified nucleoside 2 (dA EEPh , Fig.…”

The selection of a hydrophobic 7-phenylbutyl-7-deazaadenine-modified DNA aptamer with high binding affinity for the Heat Shock Protein 70

“…Synthesis of modi ed nucleoside and dA*TP For the selection and synthesis of aptamers, we needed the modi ed nucleoside triphosphate (for enzymatic synthesis) as well as the corresponding nucleoside phosphoramidite (for chemical synthesis). The synthesis started with the preparation of 7iodo-2 -deoxy-7-deazaadenosine (1, dA I ) by the modi ed reported procedure 31 where the changes in protocol resulted in overall higher yields (Supporting Information, section 1.2). dA I was further used in Pd-catalyzed Sonogashira cross-coupling with but-3-yn-1-ylbenzene in presence of TPPTS, CuI and TEA which resulted in the alkyne-linked modi ed nucleoside 2 (dA EEPh , Scheme 1A) in very good yield (93%).…”