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2′‐Deoxyuridine and 2′‐Deoxyisocytidine as Constituents of DNA with Parallel Chain Orientation: The Stabilization of the iC d ⋅G d Base Pair by the 5‐Methyl Group
Author(s) -
Seela Frank,
He Yang
Publication year - 2000
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20000906)83:9<2527::aid-hlca2527>3.0.co;2-d
Subject(s) - chemistry , phosphoramidite , oligonucleotide , nucleoside , residue (chemistry) , nucleic acid , stereochemistry , deoxyuridine , dna , base pair , oligonucleotide synthesis , combinatorial chemistry , protecting group , nucleotide , duplex (building) , biochemistry , organic chemistry , gene , alkyl
Parallel‐stranded oligonucleotides containing 2′‐deoxyuridine ( 2 ) and 2′‐deoxyisocytidine ( 4 ) were synthesized. The phosphoramidite 11 employed in the solid‐phase synthesis carries a (dimethylamino)methylidene residue as amino‐protecting group. This group stabilizes the acid‐labile glycosylic bond of 4 and enables the base‐catalyzed deprotection of oligonucleotides without degrading the nucleoside 4 residues. Oligonucleotide duplexes incorporating the 5‐Me derivatives of 2 (→2′‐deoxythymidine) and 4 (→2′‐deoxy‐5‐methylisocytidine), which are more stable than those containing the unmethylated nucleosides, were also compared. Depending on the nearest‐neighbor environment, Me groups provide an additional stabilization through Me/Me contacts or Me/backbone interactions.