- Stereochemistry of internucleotide bond formation by the H-phosphonate method. 7. Stereoselective formation of ribonucleoside (RP)- and (SP)-3′-H-phosphonothioate monoesters
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Ribonucleoside 3′-H-phosphonothioate monoesters exist in the form of (RP)- and (SP)-diastereomers. In order to obtain them in good yields and in high stereochemical purity, stereoselective strategies for their preparation were investigated. For the synthesis of the (RP)-isomer, a stereoselective sulfhydrolysis of an activated nucleoside H-phosphonate was developed, while the monoesters with an (SP)-configuration were prepared by asymmetric transformation of diastereomeric mixtures of nucleoside 3′-H-phosphonothioates using either a condensation with 9-fluorenemethanol, followed by β-elimination, or via pivaloylation-hydrolysis reaction sequence. A tentative assignment of the absolute configurations of the obtained diastereomers of 3′-H-phosphonothioate esters was carried out via a stereochemical correlation analysis.
- Sobkowski, Michal,Stawinski, Jacek,Kraszewski, Adam
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experimental part
p. 410 - 419
(2010/07/04)
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- Thiol-dependent DNA cleavage by 3H-1,2-benzodithiol-3-one 1,1-dioxide
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Hydrodisulfides (RSSH) have previously been implicated as key intermediates in thiol-triggered oxidative DNA damage by the antitumor agent leinamycin. In an effort to better understand DNA damage by RSSH and to expand on the number and type of chemical systems that produce this reactive intermediate, the ability of 3H-1,2-benzodithiol-3-one 1,1-dioxide (11) to serve as a thio-dependent DNA cleaving agent has been investigated. The findings reported here indicate that reaction of 11 with thiols results in release of RSSH and subsequent oxidative DNA strand cleavage. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Breydo, Leonid,Gates, Kent S.
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p. 885 - 889
(2007/10/03)
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- 3-H-2,1-benzoxathiol-3-one 1-oxide - A new reagent for stereospecific oxidation of nucleoside H-phosphonothioate diesters
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Oxidation of diastereomerically pure nucleoside H-phosphonothioate diesters with 3-H-2,1-benzoxathiol-3-one 1-oxide (1) was found to be stereospecific and occurred with retention of configuration. Absolute configurations of diribonucleoside H-phosphonothioate diastereomers were established via stereochemical correlation using m-chloroperoxybenzoic acid for stereospecific conversion of ribonucleoside H-phosphonothioate to the corresponding H-phosphonate diesters.
- Stawinski, Jacek,Thelin, Mats
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p. 3189 - 3192
(2007/10/02)
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- Nucleoside H-Phosphonates. 13. Studies on 3H-1,2-Benzodithiol-3-one Derivatives as Sulfurizing Reagents for H-Phosphonate and H-Phosphonothioate Diesters
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Formation of O-oxidized products during sulfurization of H-phosphonothioate and H-phosphonate diesters with 3H-1,2-benzodithiol-3-one 1,1-dioxide (1) was found to be due to generation of the O-oxidizing agents, most likely 3H-2,1-benzoxathiol-3-one 1-oxide (4) and 3H-2,1-benzoxathiol-3-one (5), during the course of the reactions.Another source of the side products formation may be the disproportionation of 1 that occurs in the presence of triethylamine.To overcome these problems, a new sulfur-transferring reagent, 3H-1,2-benzodithiol-3-one (3), has been developed.Under aqueous reaction conditions, which are compartible with both solution and solid-phase synthesis of oligonucleotides, the reagent 3 furnished clean and fast conversion of H-phosphonothioate and H-phosphonate diesters into the corresponding phosphorodi- and phosphoromonothioates.
- Stawinski, Jacek,Thelin, Mats
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p. 5169 - 5175
(2007/10/02)
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