The p-Nitrophenylethyl Group - An Universal Blocking Group in Nucleoside and Nucleotide Chemistry

Synthesis and reactivity of intermediates formed in the T4RNA ligase reaction

“…5'-0-(9-phenylxanthene-9-yl)thymidine could be phosphorylated with 2,4-dichlorophenyl-O,O-bis(l-benzotriazolyl)phosphate ( 14) and the initially formed monobenzotriazolyl adduct converted to the triester j1 (Scheme 1) by the addition of 4-nitrophenylethanol and a small amount of N-methylimidazole. The triester 1. could ultimately be converted to a 3'-phosphomonoester first by reaction with the oximate anion to remove the 2,4dichlorophenyl group (25) and in a second step, reaction with a strong base to remove the 4-nitrophenyl ethyl group by B-elimination (18,26,27). After removal of the 5' protecting group, the triester 2.& was reacted with morpholino-O,O-bis(l-benzotriazaoly)phosphate (4, 17, 20) to form the bisphosphotriester 3a.…”

Nucleobase Protection of Deoxyribo‐ and Ribonucleosides

“…Allyloxycarbonyl protecting groups (Hayakawa, Kato, Uchiyama, Kajino, & Noyori, ; Hayakawa, Wakabayashi, Kato, & Noyori, ; Hyodo, & Hayakawa, ) have also been introduced and can be chemoselectively removed under neutral [using Pd(0)] or mildly basic conditions. However, the p ‐nitrophenylethyl (NPE) and ( p ‐nitrophenyl)ethoxycarbonyl (NPEOC) groups (Pfleiderer et al, ; Pfleiderer, ; Pfister, Farkas, Charubala, & Pfleiderer, ; Schirmeister & Pfleiderer, ; Trichtinger et al, ) and the 2‐dansylethoxy cabonyl group (Wagner & Pfleiderer, ) are selectively removed using DBU following a β ‐elimination nucleobase protection strategy. The NPE/NPEOC β ‐elimination nucleobse‐protection strategy in conjunction with a succinyl linker has been used for the preparation of oligonucleotide arrays and high‐quality primers (Weiler & Hoheisel, ) by solid‐phase synthesis.…”

Nucleobase Protection of Deoxyribo‐ and Ribonucleosides

“…(5) Himmelsbach et al, 1984Pfleiderer et al, 1985Pfister and Pfleiderer, 1989 -Happ et al, 1987Hagen and Chládek, 1989Heikkilä and Chattopadhyaya, 1983Marugg et al, 1984Nagaich and Misra, 1989 4-nitrophenylethyloxycarbonyl Nyilas et al, 1988 G (N2); A (N6); C (N4) Brown et al, 1989Rao et al, 1987Tanimura et al, 1988Schaller et al, 1963Balgobin et al, 1981 Köster et al, 1981Sinha et al, 1993Boal et al, 1996 4-(tert-butyl)phenoxyacetyl diphenylacetyl 3,4-dichlorobenzoyl 3-methoxy-4-phenoxybenzoyl and removal of N-acyl protecting groups can also be achieved by enzymatic methods (Prasad and Wengel, 1996).…”

“…New protecting groups have also been introduced that can be chemoselectively removed under neutral or mildly basic conditions. Indeed, the allyloxycarbonyl protecting group (Hayakawa et al, 1986(Hayakawa et al, , 1990) is chemoselectively removed using Pd(0), whereas the (p-nitrophenyl)ethoxycarbonyl group (Trichtinger et al, 1983;Pfleiderer et al, 1985;Pfister et al, 1988) and the 2-dansylethoxy cabonyl group Current Protocols in Nucleic Acid Chemistry 2.1.12 Nucleobase Protection of Deoxyribo-and Ribonucleosides (Wagner and Pfleiderer, 1997) are selectively removed using DBU. Consequently, supportbound oligonucleotides can be prepared using building blocks that carry these protecting groups.…”