title: Synthesis and duplex stability of oligonucleotides containing cytosine-thymine analogues.
abstract: The synthesis of the deoxynucleoside derived from the base P, 6H,8H-3,4-dihydro-pyrimido[4,5-c] [4,5-c] [1,2]oxazin-7-one, 2, and its introduction by established phosphoramidite and H-phosphonate chemistry into oligonucleotides is described. The melting transition temperatures (Tm) of a range of heptadecamer duplexes containing P/A and P/G base-pairs are compared with corresponding ones having N4-methoxycytosine (M) 1 and mismatched normal bases. P/A and P/G pairs allow closely similar duplex stabilities and have the potential to reduce the multiplicity of probes and primers based on amino acid sequences by removing the T/C degeneracy.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: P K
authors.initials: PK
authors.lastname: Lin
authors.forename: D M
authors.initials: DM
authors.lastname: Brown
mesh_terms: D000577:Amides; D001482:Base Composition; D001483:Base Sequence; D055598:Chemical Phenomena; D002621:Chemistry; D003596:Cytosine / Q000031:analogs & derivatives*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D063065:Organophosphonates; D010078:Oxazines; D010756:Phosphoric Acids; D011119:Polynucleotides / Q000138:chemical synthesis*; D011743:Pyrimidines; D013941:Thymine / Q000031:analogs & derivatives*
chemical_list: D000577:Amides; D063065:Organophosphonates; D010078:Oxazines; D010756:Phosphoric Acids; D011119:Polynucleotides; D011743:Pyrimidines; C062254:6H,8H-3,4-dihydropyrimido(4,5-c)(1,2)oxazin-7-one; D003596:Cytosine; C011067:phosphoramidic acid; D013941:Thymine