Artificial bioconjugates with naturally occurring linkages: the use of phosphodiester

• Takao Shoji,
• Hiroki Fukutomi,
• Yohei Okada and
• Kazuhiro Chiba

Beilstein J. Org. Chem. 2018, 14, 1946–1955, doi:10.3762/bjoc.14.169

• linkages that can be formed between native functional groups would be safe alternatives, and are known as natural conjugates such as nucleopeptides and nucleolipids [49]. We have been developing alkyl chain soluble support (ACSS)-assisted liquid-phase methods, specifically for peptide and oligonucleotide

Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

• Ruth Suchsland,
• Bettina Appel and
• Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

• on soluble polymers, and their use as synthons in standard DNA synthesis. Keywords: gene library; protein engineering; soluble support; synthesis; trinucleotide; Introduction Protein engineering is a highly actual research area with a number of potential applications [1][2][3][4]. The construction

• well suited to it. Also the solution-phase synthesis of protected trinucleotide building blocks has been described in the literature [21][22][23]. In an initial attempt, thymidine as a start nucleoside was tethered to a precipitative tetrapodal soluble support via a disulfide-linker [21] (Table 1

• reductive conditions (disulfide cleavage or hydrogenation) or under mild basic conditions leaving all protecting groups at the trimer undamaged. In particular, soluble support strategies have great potential for an efficient large scale synthesis of fully protected trinucleotides. The essential feature here

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• to kilogram scale. In spite of this, solution-phase synthesis has received continuous interest, on one hand as a technique that could enable synthesis of even larger amounts and, on the other hand, as a gram scale laboratory synthesis without any special equipment. The synthesis on a soluble support

• . While P(III)-based phosphoramidite and H-phosphonate chemistries are almost exclusively used on a solid support, the “outdated” P(V)-based phosphotriester chemistry still offers one major advantage for the synthesis on a soluble support; the omission of the oxidation step simplifies the coupling cycle

• , none of them has really tested at such a scale that the feasibility of their industrial use could be critically judged. Keywords: DNA; oligonucleotides; RNA; soluble support; synthesis; Introduction The synthesis of oligonucleotides (ONs) consists of linking nucleosides to each other in a specified

Preparation of a disulfide-linked precipitative soluble support for solution-phase synthesis of trimeric oligodeoxyribonucleotide 3´-(2-chlorophenylphosphate) building blocks

• Amit M. Jabgunde,
• Alejandro Gimenez Molina,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2015, 11, 1553–1560, doi:10.3762/bjoc.11.171

• of a disulfide-tethered precipitative soluble support and its use for solution-phase synthesis of trimeric oligodeoxyribonucleotide 3´-(2-chlorophenylphosphate) building blocks is described. To obtain the building blocks, N-acyl protected 2´-deoxy-5´-O-(4,4´-dimethoxytrityl)ribonucleosides were

• -protected oligodeoxyribonucleotide trimer 3’-pTpdCBzpdGibu-5’ as its 3’-(2-chlorophenyl phosphate) was achieved by reductive cleavage of the disulfide bond. Keywords: disulfide linker; oligodeoxyribonucleotides; phosphotriester chemistry; precipitation; soluble support; Introduction Synthetic nucleic

• , the disulfide linkage may be reductively cleaved and the phosphate bound 2-mercaptoethyl group is removed. Accordingly, the oligomer expectedly is released in a fully protected form. We now report on the synthesis of such a soluble support, 3, and show that it allows efficient coupling by the 1

Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

• Tommaso Pecchioli,
• Manoj Kumar Muthyala,
• Rainer Haag and
• Mathias Christmann

Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83

• and 4b showed poor solubility in solvents with low polarity, thus allowing for an easy recovery in 60–70% yield after selective precipitation using Et2O. The utility of our soluble support was examined in the catalytic efficiency of recovered PG-57 (4b) (Table 7). Catalyst 4b was used three times in

• afforded higher yields and selectivities, confirming the strong influence of the substituent (Table 5, entries 4 and 5). Contrarily, aliphatic enals 14a,b were well-tolerated and the outcomes were not affected significantly (Table 5, entries 1 and 2). In our studies on the utilization of hPG as a soluble

• support in organocatalysis, hyperbranched PG-95 (4a) and PG-57 (4b) were finally compared with the monovalent G1-dendron imidazolidin-4-one 8 previously prepared and the original MacMillan’s first generation catalyst 16 using the optimum conditions (Table 6). As shown in Table 6, multivalent 4b and

Solution phase synthesis of short oligoribonucleotides on a precipitative tetrapodal support

• Alejandro Gimenez Molina,
• Amit M. Jabgunde,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2014, 10, 2279–2285, doi:10.3762/bjoc.10.237

• been elaborated. Novel 2'-O-(2-cyanoethyl)-5'-O-(1-methoxy-1-methylethyl) protected ribonucleoside 3'-phosphoramidites have been prepared and their usefulness as building blocks in RNA synthesis on a soluble support has been demonstrated. As a proof of concept, a pentameric oligoribonucleotide, 3

• in high yields. Keywords: nucleic acids; oligoribonucleotides; phosphoramidite; soluble support; synthesis; Introduction Recognition of short noncoding RNAs as regulatory elements of gene expression [1][2][3][4][5] has attracted interest in their physico-chemical properties, including structure

• them has so far been applied to the synthesis of RNA. Tetrakis(4-azidomethylphenyl)pentaerythritol has recently been introduced as a practical soluble support for the synthesis of short oligodeoxyribonucleotides [16]. The 3'-terminal nucleoside is attached as a 3'-O-(4-pentynoyl) derivative to the