Synthesis of 4-substituted 1H-benzimidazole 2'-deoxyribonucleosides and utility of the 4-nitro compound as universal base
Autor(en): | Seela, F Bourgeois, W Rosemeyer, H Wenzel, T |
Stichwörter: | ASSIGNMENT; BENZIMIDAZOLE; C-13 MAGNETIC RESONANCE; CHEMICAL-SHIFTS; Chemistry; Chemistry, Multidisciplinary; DNA; PURINE | Erscheinungsdatum: | 1996 | Herausgeber: | NEW SWISS CHEMICAL SOC | Journal: | HELVETICA CHIMICA ACTA | Volumen: | 79 | Ausgabe: | 2 | Startseite: | 488 | Seitenende: | 498 | Zusammenfassung: | The stereoselective synthesis of 4-substituted 1H-benzimidazole 2'-deoxyribonucleosides is described. Regioisomeric (N-1 and N-3) beta-D-deoxyribonucleosides 2a-c and 3a-c were formed. C-13-NMR Chemical shifts of the 1H-benzimidazole 2'-deoxy-beta-D-ribofuranosides were correlated with point charges of C-atoms as well as with Hammett constants of the exocyclic substituents. Phosphonate and phosphoramidite building blocks of 4-nitro-1H-benzimidazole 2'-deoxyribofuranoside (2a) were prepared (see 4a, b). Oligonucleotides of the d(A(20)) type were synthesized in which the two central dA bases were replaced by 4-nitro-1H-benzimidazole residues. They were hybridized with oligomeric dT and related oligomers having the other conventional bases opposite to the 4-nitro-1H-benzimidazole moieties. Within these duplexes (12 . 13, 12 . 14, 12 . 15, and 12 . 16), the destabilization was almost independent of the mismatch which is required for a universal base. The thermodynamic data indicate that the 4-nitro-1H-benzimidazole residues do not form H-bonds with opposite bases but are stabilizing the duplex by stacking interactions and favorable entropic changes. |
ISSN: | 0018019X | DOI: | 10.1002/hlca.19960790216 |
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geprüft am 13.05.2024