- Modulating the Stability of 2-Pyridinyl Thermolabile Hydroxyl Protecting Groups via the "chemical Switch" Approach
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A novel and effective method is presented for modulating the stability of 2-Pyridinyl Thermolabile Protecting Groups (2-Py TPGs) in the "chemical switch" approach. The main advantage of the discussed approach is the possibility of changing the nucleophili
- Witkowska, Agnieszka,Krygier, Dominika,Brzezinska, Jolanta,Chmielewski, Marcin K.
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- THERMALLY-CLEAVABLE PROTECTING AND LINKER GROUPS
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The present invention relates to chemical linkers and protecting groups, compounds and compositions containing the chemical linkers or protecting groups, and intermediates and processes that can be used to prepare them. The chemical linkers and protecting groups are based on pyrrolidine and piperidine activating groups, which undergo intramolecular cyclisation upon heating with release of carbon dioxide, thereby releasing the organic compound from a substrate. In particular, those chemical linkers and protecting groups are useful in the solid phase synthesis of oligonucleotides according to the following representative schemes.
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Page/Page column 8; 70-72
(2018/11/10)
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- Semisynthetic peptide-lipase conjugates for improved biotransformations
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An efficient chemoselective method for the creation of semisynthetic lipases by site-specific incorporation of tailor-made peptides on the lipase-lid site was developed. These new enzymes showed excellent improved specificity and regio- or enantioselectivity in different biotransformations.
- Romero, Oscar,Filice, Marco,Guisan, Jose M.,Palomo, Jose M.,De Las Rivas, Blanca,Carrasco-Lopez, Cesar,Hermoso, Juan A.,Klett, Javier,Morreale, Antonio,Abian, Olga
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supporting information
p. 9053 - 9055,3
(2020/08/31)
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- Novel thermolabile protecting groups with higher stability at ambient temperature
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Novel thermolabile hydroxyl protecting groups of increased thermostability are proposed. The stability of these groups at different temperatures ranges has been determined. The 2-pyridyl-N-(2,4-difluorobenzyl)aminoethyl unit was selected as stable at ambient temperature and very labile at increased temperature. The half-life times for the best groups were established. Application of this chemistry to the protection of different hydroxyl groups of thymidine was also demonstrated.
- Chmielewski, Marcin K.
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p. 666 - 669
(2012/02/15)
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- CHEMICALLY MODIFIED NUCLEOSIDE 5'-TRIPHOSPHATES FOR THERMALLY INITIATED AMPLIFICATION OF NUCLEIC ACID
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Provided herein are methods and compositions for nucleic acid amplification. These methods involve the use of 3'-substituted nucleoside 5'-triphosphates or 3'-substituted terminated primers in nucleic acid amplification reactions. In certain aspects, the methods are accomplished by use of 3'-substituted NTPs and/or 3'-substituted terminated primers which provide utility in nucleic acid amplification. In preferred embodiments, the NTPs and/or primers are substituted at the 3'-position with particular heat labile chemical groups such as ethers, esters or carbonate esters.
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Page/Page column 59-60
(2010/01/07)
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- Protecting groups transfer: Unusual method of removal of tr and TBDMS groups by transetherification
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The triphenylmethyl (Tr) group undergoes a transfer (transetherification or disproportionation) between the molecules of 5'-O-Tr-2'-deoxynucleosides in a process mediated by anhydrous sulfates of Cu+2, Fe+2, or Ni+2 to yield mixtures of 3',5'-bis-O-Tr and 3'-O-Tr products. If phenylmethanol is present in a reaction medium, detritylation results with concomitant formation of phenylmethyl triphenylmethyl ether. The behavior of t-butyldimethylsilyl (TBDMS) group in 5'-O-TBDMS-2'-deoxynucleosides is exactly the same. Such type of transetherifications was not observed before for the O-Tr and O-TBDMS groups. Copyright Taylor & Francis Group, LLC.
- Cabral, Nadia L. D.,Thiessen, Luciano Hoeltgebaum,Doboszewski, Bogdan
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p. 931 - 948
(2008/12/21)
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- Thermolytic Carbonates for Potential 5′-Hydroxyl Protection of Deoxyribonucleosides
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Thermolytic groups structurally related to well-studied heat-sensitive phosphate/thiophosphate protecting groups have been evaluated for 5′-hydroxyl protection of deoxyribonucleosides as carbonates and for potential use in solid-phase oligonucleotide synthesis. The spatial arrangement of selected functional groups forming an asymmetric nucleosidic 5′-O-carbonic acid ester has been designed to enable heat-induced cyclodecarbonation reactions, which would result in the release of carbon dioxide and the generation of a nucleosidic 5′-hydroxyl group. The nucleosidic 5′-O-carbonates 3-8, 10-15, and 19-21 were prepared and were isolated in yields ranging from 45 to 83%. Thermolytic deprotection of these carbonates is preferably performed in aqueous organic solvent at 90 °C under near neutral conditions. The rates of carbonate deprotection are dependent on the nucleophilicity of the functional group involved in the postulated cyclodecarbonation reaction and on solvent polarity. Deprotection kinetics increase according to the following order: 4 5 10 6 12 7 13 8 14 ? 19-21 and CC14 dioxane MeCN t-BuOH MeCN:phosphate buffer (3:1 v/v, pH 7.0) EtOH:phosphate buffer (1:1 v/v, pH 7.0). Complete thermolytic deprotection of carbonates 7, 8, 13, and 14 is achieved within 20 min to 2 h under optimal conditions in phosphate buffer-MeCN. The 2-(2-pyridyl)amino-1-phenylethyl and 2-[N-methyl-N-(2-pyridyl)]aminoethyl groups are particularly promising for 5′-hydroxyl protection of deoxyribonucleosides as thermolytic carbonates.
- Chmielewski, Marcin K.,Marchan, Vicente,Cieslak, Jacek,Grajkowski, Andrzej,Livengood, Victor,Muench, Ursula,Wilk, Andrzej,Beaucage, Serge L.
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p. 10003 - 10012
(2007/10/03)
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- Conformational Transmission in Nucleotides Containing Trigonal Bipyramidal Phosphorus as the Internucleoside Linkage
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A set of nucleotide analogues containing a stable trigonal bipyramidal phosphorus (PV TBP) moiety (5-11) has been developed, and their conformational properties were studied with 300- and 500-MHz 1H NMR.In the solvent acetone-d6, it is found that the conformation of the model compounds is determined by a hydrogen bond between the backbone atom O5', and the base proton H6 (pyrimidine base) or H8 (purine base), resulting in a preference for the standard gauche(+) conformation around the C4'-C5' bond.In the hydrogen bond disrupting solvent DMSO-d6, the PV TBP nucleotides 5-8 clearly show conformational transmission, i.e., a preference for the unusual gauche(-) (g-) rotamer around the C4'-C5' bond is found.This structural distortion opposes stacking of the bases, as is confirmed by the observation that the preference for g- is strongest for 7 and 8, in which stacking is eliminated.The present results provide support to our earlier proposition that formation of PV TBP locations in DNA can lead to a marked change of the secondary structure (Buck, H.M.Recl.Trav.Chim.Pays-Bas 1980, 99, 181).
- Koole, Leo H.,Genderen, Marcel H. P. van,Buck, Henk M.
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p. 5266 - 5272
(2007/10/02)
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