2140-73-0Relevant academic research and scientific papers
Noncanonical RNA Nucleosides as Molecular Fossils of an Early Earth—Generation by Prebiotic Methylations and Carbamoylations
Schneider, Christina,Becker, Sidney,Okamura, Hidenori,Crisp, Antony,Amatov, Tynchtyk,Stadlmeier, Michael,Carell, Thomas
supporting information, p. 5943 - 5946 (2018/04/30)
The RNA-world hypothesis assumes that life on Earth started with small RNA molecules that catalyzed their own formation. Vital to this hypothesis is the need for prebiotic routes towards RNA. Contemporary RNA, however, is not only constructed from the four canonical nucleobases (A, C, G, and U), it also contains many chemically modified (noncanonical) bases. A still open question is whether these noncanonical bases were formed in parallel to the canonical bases (chemical origin) or later, when life demanded higher functional diversity (biological origin). Here we show that isocyanates in combination with sodium nitrite establish methylating and carbamoylating reactivity compatible with early Earth conditions. These reactions lead to the formation of methylated and amino acid modified nucleosides that are still extant. Our data provide a plausible scenario for the chemical origin of certain noncanonical bases, which suggests that they are fossils of an early Earth.
Kinetics and mechanism of the defluorination of 8-fluoropurine nucleosides in basic and acidic media
Liu, Jie,Barrio, Jorge R.,Satyamurthy, Nagichettiar
, p. 1175 - 1187 (2008/12/20)
For investigating the stability of C(8)-fluorine bond in 8-fluoropurine nucleosides some protected 8-fluoroguanosine, 8-fluoroinosine and 8-fluoroadenosine derivatives were prepared by direct fluorination of acetyl-protected purine nucleosides with elemental fluorine in solvents such as chloroform, acetonitrile and nitromethane. Fluorination reactions conducted in chloroform medium gave better yields of 8-fluoropurines. The fluorination yields were slightly lower when acetonitrile or nitromethane was used as solvent, but the product purification was found to be much easier. When the synthesized, protected fluoronucleosides were subjected to standard basic (NH3 in methanol or 2-propanol) and acidic (HCl in methanol) deprotection conditions relevant to nucleoside chemistry, an efficient defluorination reaction took place. The kinetics of these defluorination reactions were conveniently followed, under pseudo-first-order reaction conditions, using 19F NMR spectroscopy. 1H NMR, LC-MS and mass spectroscopy identified the products of the kinetic reaction mixtures. The defluorination reaction rate constants (kobs) in basic media depended upon the electron density at C(8) while the kobs data in acidic medium were determined by the pKa of N7. An addition-elimination based mechanism (SNAr) has been proposed for the defluorination reactions of these 8-fluoropurine nucleosides.
The Synthesis of 2′-O-[(Triisopropylsilyl)oxy] methyl (TOM) Phosphoramidites of Methylated Ribonucleosides (m1G, m2G, m22G, m1I, m3U, m4C, m6A, m62A) for Use in Automated RNA Solid-Phase Synthesis
Hoebartner, Claudia,Kreutz, Christoph,Flecker, Elke,Ottenschlaeger, Elke,Pils, Werner,Grubmayr, Karl,Micura, Ronald
, p. 851 - 873 (2007/10/03)
The straightforward synthesis of eight methylated ribonucleoside phosphoramidites is described. These building blocks allow for incorporation of the naturally occuring nucleosides 1-methylguanosine (m1G), N 2-methylguanosine (m2G), N2N 2-dimethylguanosine (m22G), 1-methylinosine (m1I), 3-methyluridine (m3U), N4- methylcytidine (m4C), N6-methyladenosine (m6A), and N6,N6-dimethyladenosine (m62A) into oligoribonucleotides by automated RNA solid-phase synthesis. In all cases, the ribose 2′-hydroxyl group of the building blocks is masked by the recently introduced [(triisopropylsilyl)oxy]methyl (TOM) group.
Micellar Methylating Agents: (Long-chain-alkyl)dimethylsulphonium Iodides
Yamauchi, Kiyoshi,Hisanaga, Yorisato,Kinoshita, Masayoshi
, p. 1941 - 1942 (2007/10/02)
Dodecyl-, hexadecyl-, and octadecyl-dimethylsulphonium iodide were found to methylate efficiently various nucleosides, hydroxy aromatic compounds, and thiols at pH 8-11 and 50 - 70 deg C.The optimum conditions and the mechanism of the reaction are discussed briefly in relation to the micellar reaction characteristics.
The Methylation of Ribonucleosides by Trimethyl Phosphate or Dimethyl Sulfate in the Presence of Boric Acid
Hisanaga, Yorisato,Tanabe, Toshizumi,Yamauchi, Kiyoshi,Kinoshita, Masayoshi
, p. 1569 - 1570 (2007/10/02)
Uridine, inosine, adenosine, and thymidine were methylated selectively at the base moieties by the use of trimethyl phosphate or dimethyl sulfate in the presence of boric acid.A suppressing effect of boric acid on the methylation of the ribose-hydroxyl groups was discussed briefly.
Methylation study of ribonucleosides, deoxyribonucleosides, and 2′-O-methylribonucleosides with trimethylsulphonium hydroxide and trimethylsulphonium iodide. Influence of the 2′-hydroxy-groups on the reactivity of the base moieties of ribonucleosides
Yamauchi, Kiyoshi,Nakagima, Toru,Kinoshita, Masayoshi
, p. 2787 - 2792 (2007/10/02)
Methylations of the naturally occuring ribonucleoside (1), deoxyribonucleoside (2), and 2′-O-methylribonucleoside (3) were carried out using trimethylsulphonium hydroxide (Me3SOH) and trimethylsulphonium iodide (Me3Sl). The base moiety of (2) and (3) are more reactive than the corresponding base moiety of (1). The sites and extent of methylation of (2) are considerably different from those of (1), but are almost identical with those of (3). The reactivities of (1)-(3) are discussed in connection to an intramolecular interaction of the 2′-OH groups with the base moiety of (1). The methylating characteristics of Me 3SOH and Me3Sl are also described. The kinetics indicate an SN2 mechanism for methylation of nucleosides by Me 3S+ ions.
