112141-36-3Relevant articles and documents
Nucleotides. Part LXV. Synthesis of 2'-Deoxyribonucleoside 5'-Phosphoramidites: New Building Blocks for the Inverse (5'-3')-Oligonucleotide Approach
Wagner, Thomas,Pfleiderer, Wolfgang
, p. 2023 - 2035 (2007/10/03)
The syntheses of the 3'-O-(4,4'-dimethoxytrityl)-protected 5'-phosphoramidites 25-28 and 5'-(hydrogen succinates) 29-32, which can be used as monomeric building blocks for the inverse (5'-3')-oligodeoxyribonucleotide synthesis are described (Scheme). These activated nucleosides and nucleotides were obtained by two slightly different four-step syntheses starting with the base-protected nucleosides 13-20. For the protection of the aglycon residues, the well-established 2-(4-nitrophenyl)ethyl (npe) and [2-(4-nitrophenyl)ethoxy]carbonyl (npeoc) groups were used. The assembly of the oligonucleotides required a slightly increased coupling time of 3 min in application of the common protocol (see Table 1). The use of pyridinium hydrochloride as an activator (instead of 1H-tetrazole) resulted in an extremely shorter activation time of 30 seconds. We established the efficiency of this inverse strategy by the synthesis of the oligonucleotide 3'-conjugates 33 and 34 which carry lipophilic caps derived from cholesterol and vitamin E, respectively, as well as by the formation of (3'-3')- and (5'-5')-internucleotide linkages (see Table 2).
Nucleosides. Part LI. The 2-(4-Nitrophenyl)ethoxycarbonyl (npeoc) and 2-(2,4-Dinitrophenyl)ethoxycarbonyl (dnpeoc) Groups for Protection of Hydroxy Functions in Ribonucleosides and 2'-Deoxyribonucleosides
Schirmeister, Helga,Himmelsbach, Frank,Pfleiderer, Wolfgang
, p. 385 - 401 (2007/10/02)
The common 2'-deoxypyrimidine and -purine nucleosides, thymidine (4), O4-thymidine (17), 2'-deoxy-N4-cytidine (26), 2'-deoxy-N6-adenosine (39), and 2'-deoxy-N2--O6-guanosine (52) were further protected by the 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) and the 2-(2,4-dinitrophenyl)ethoxycarbonyl (dnpeoc) group at the OH functions of the sugar moiety to form new partially and fully blocked intermediates for nucleoside and nucleotide syntheses.The corresponding 5'-O-monomethoxytrityl derivatives 5, 18, 30, 40, and 56 were also used as starting material to synthesize some other intermediates which were not obtained by direct acylations.In the ribonucleoside series, the 5'-O-monomethoxytrityl derivatives 14, 36, 49, and 63 reacted with 2-(4-nitrophenyl)ethyl chloroformate (1) to the corresponding 2',3'-bis-carbonates 15, 37, 50, and 64 which were either detritylated to 16, 38, 51, and 65, respectively, or converted by 1,8-diazabicycloundec-7-ene (DBU) treatment to the 2',3'-cyclic carbonates 66-69.The newly synthesized compounds were characterized by elemental analyses and UV and 1H-NMR spectra.
