- Synthesis and DNA incorporation of an ethynyl-bridged cytosine C-nucleoside as guanosine surrogate
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(Chemical Equation Presented) As a guanosine mimic that lacks the preference for syn or anti conformation a cytosine C-nucleoside was synthesized connecting the nucleobase at the anomeric center by an ethynyl linker. The key step was a Sonogashira cross coupling of 5-iodocytosine with 1′-ethynyl-2′-deoxyribose. The new C-nucleoside incorporated into G/C-alternating oligonucleotides emerged as guanosine substitute, however, with reduced duplex stability. B-Form DNA was strongly stabilized by the new surrogate even in typically Z-DNA forming sequences and in Z-form inducing environment.
- Heinrich, Daniel,Wagner, Thomas,Diederichsen, Ulf
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p. 5311 - 5314
(2008/09/17)
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- Synthesis of a 1′-aminomethylthymidine and oligodeoxyribonucleotides with 1′-acylamidomethylthymidine residues
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Reported here is a 10-step synthesis of a phosphoramidite building block of 1′-aminomethylthymidine that starts from 2-deoxyribose. The framework of the branched aminonucleoside was elaborated from a known 1-cyano-1-bromo glycosyl donor, whose reaction with the silylated nucleobase furnished the 1′-cyanide, which was reduced to the desired aminomethylnucleoside. The N-allyloxycarbonyl (Alloc)-protected nucleoside was converted to a phosphoramidite building block and incorporated into the oligonucleotides 5′-GCAT*TATTAC-3′, and 5′-GCAT*TAT*TAC- 3′, where T* denotes 1′-acylamidomethylthymidine residues. Removal of the Alloc protecting group and acylation with the residue of pyrene-1-yl-butanoic acid were achieved on support, using microwave irradiation to ensure full conversion. The UV-melting point of the duplex of the singly and doubly modified decamers with their fully complementary target sequence is 0.1-6.9 °C higher than that of the unmodified control duplex, depending on the salt concentration. This suggests that the aminomethyl linker may allow for the placing of a functional "payload" in the minor groove of DNA duplexes without disrupting the helix. Oligonucleotides thus endowed with functional modifications may become useful for biomedical applications.
- Gruenefeld, Peter,Richert, Clemens
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p. 7543 - 7551
(2007/10/03)
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- Steric fixation of bromovinyluracil: Synthesis of furo[2,3-d]pyrimidine nucleosides
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A new synthetic proccdure for the preparation of 5,6-dihydrofuro[2,3-d]pyrimidin-2(3H)-one (3) and its deoxyriboside 8 is reported. Compound 3 undergoes nucleophilic reactions with various agents to yield 5-substituted uracil derivatives. The dehydro derivative of 3, furo[2,3-d]pyrimidin-2(3H)-one (18) was synthesized by cyclization of BVU 15, which made us develop a reproducible and high yield method for the synthesis of BV(D)U. Starting from 18, the α-deoxyriboside 20 and the β-riboside 22 were prepared.
- Eger,Jalalian,Schmidt
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p. 211 - 218
(2007/10/02)
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- Synthesis of a potential antiviral compound: 5-Bromoethynyl-2'- deoxyuridine
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5-Bromoethynyluracil and its deoxyriboside can be prepared in good yields starting from dibromovinyluracil, which is accesible by literature methods. 5-Bromoethynyl-deoxyuridine is less effective against HSV-1 than E- (bromovinyl)-deoxyuridine but, similar to BVDU, seems to exhibit a certain selectivity toward HSV-1. Molecular calculations prove the spatial similarity of both compounds.
- Eger,Jalalian,Schmidt
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p. 8371 - 8380
(2007/10/02)
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