Synthesis and biological evaluation of a series of thieno-expanded tricyclic purine 2′-deoxy nucleoside analogues
摘要:
Introducing structural diversity into the nucleoside scaffold for use as potential chemotherapeutics has long been considered an important approach to drug design. In that regard, we have designed and synthesized a number of innovative 2'-deoxy expanded nucleosides where a heteroaromatic thiophene spacer ring has been inserted in between the imidazole and pyrimidine ring systems of the natural purine scaffold. The synthetic efforts towards realizing the expanded 2'-deoxy-guanosine and -adenosine tricyclic analogues as well as the preliminary biological results are presented herein. (C) 2012 Elsevier Ltd. All rights reserved.
Synthesis and Properties of Oligonucleotides with Iodo-Substituted Aromatic Aglycons: Investigation of Possible Halogen Bonding Base Pairs
摘要:
[GRAPHICS]Ab initio calculations of halogen bond energies of artificial base pairs constructed between iodinated aromatic nucleobase mimics and nitrogen-containing acceptor molecules such as pyridine and imidazole suggest that modified base pairs are converted to optimized planar base pairs with weak Delta E values of -0.19 to -3.93 kcal/mol. To evaluate the contribution of halogen bonding toward duplex stabilization of such modified nucleobase mimics introduced into artificial base pairs, we synthesized three C-nucleoside analogues 1-3 with several iodinated aromatic rings and an imidazole nucleoside derivative 4 and incorporated them into oligodeoxynucleotides. Hybridization studies of modified oligodeoxynucleotides incorporating iodoaromatic bases showed their unique universal base-like ability; however, no indication of halogen bond formation was observed. A more sophisticated design is required for the development of new base pairs stabilized by halogen bonding.