- Lactobacillus Fermentum N-Desoxyribosyl Transferases and the Use Thereof for Enzymatic Synthesis of 2', 3' - Didesoxynucleosides and 2',3'- Didehydro-2',3'- Didesoxynucleosides
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The inventive method for evaluating an X protein encoded by an Lactobacillus fermentum (L. fermentum ) ntd gene in such a way that the characteristics thereof are modified consists a) in obtaining the Lactobacillus fermentum (L. fermentum ) ntd gene mutants by random mutagenesis, b) in transforming cells containing a [P-] phenotype provided with vectors containing mutated nucleic acids obtained at the stage a) coding for the thus modified X* proteins, wherein P- means that said cells are auxotrophic for a substance P produced by the action of X on a natural substrate S, c) in culturing said cells in a medium comprising a substrate S*, wherein S* is an analog to the natural substrate S of the protein X and d) in selecting the cells [P-::X*] which survived at the stage c) and ijn which the proteins X* are capable of carrying out the biosynthesis of the product P based on the substrate S*. The mutated L. fermentum N-desoxyribosyl transferases have an N-didesoxyribosyl transferase activity, corresponding nucleic acids, expression vectors, host cells containing said vectors and an application for the enzymatic synthesis of 2′,3′-didesoxynucleosides and 2′,3′-didehydro-2′,3′-didesoxynucleosides.
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Page/Page column 6-8
(2008/06/13)
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- Expeditious syntheses of sugar-modified nucleosides and collections thereof exploiting furan-, pyrrole-, and thiophene-based siloxy dienes
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A series of individual sugar-modified pyrimidine nucleosides including enantiomerically enriched 2',3'-dideoxynucleosides 14a-c (α and β anomers of L- and D-series), 2',3'-dideoxy-4'-thionucleosides 21a-c (α and β anomers of L- and D-series), and 2',3'-dideoxy-4'-azanucleosides 28a-c (β anomers of L- and D-series) were synthesized, with uniform chemistry and high stereochemical efficiency, exploiting a triad of versatile heterocyclic siloxy dienes, namely, 2-(tert-butyldimethylsiloxy)furan (TBSOF), 2-(tert- butyldimethylsiloxy)thiophene (TBSOT), and N-(tert-butoxycarbonyl)-2-(tert- butyldimethylsiloxy)pyrrole (TBSOP). The synthetic procedure advantageously used both enantiomers of glyceraldehyde acetonide (D-1 and L-1) as sources of chirality and as synthetic equivalents of the formyl cation. The outlined chemistry also allowed for the rapid assemblage of a 30-member collection of racemic nucleosides (D,L-L) as well as one 15-member ensemble of chiral analogues (L-L), along with some related sublibraries.
- Rassu, Gloria,Zanardi, Franca,Battistini, Lucia,Gaetani, Enrico,Casiraghi, Giovanni
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p. 168 - 180
(2007/10/03)
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- A Highly Stereoselective Synthesis of Anti-HIV 2',3'-Dideoxy- and 2',3'-Didehydro-2',3'-dideoxynucleosides
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A general total synthesic method for the stereocontrolled synthesis of 2',3'-dideoxy- as well as 2',3'-didehydro-2',3'-dideoxynucleosides is presented.Introduction of an α-phenylselenenyl group at the 2-position of 2,3-dideoxyribosyl acetate directs the glycosyl bond formation to give >/=95percent β-isomer.This 2'-phenylselenenyl nucleoside may be converted to either the 2',3'-dideoxynucleoside by treatment with n-Bu3SnH and Et3B at room temperature or to the unsaturated derivative by treatment with H2O2/cat. pyridine.The application of this method to the syntheses of pyrimidines (ddU, ddT, ddC), 6-substituted purines (ddA, ddI, 6-chloro-ddP, N6-Me-ddA), and 2,6-disubstituted purines (2-F-ddA, 6-chloro-2-amino-ddP) as well as selected 2',3'-didehydro-2',3'-dideoxy derivatives is reported.
- Beach, J. Warren,Kim, Hea O.,Jeong, Lak S.,Nampalli, Satyanarayana,Islam, Qamrul,et al.
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p. 3887 - 3894
(2007/10/02)
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- Synthesis of the Dideoxynucleosides ddC and CNT from Glutamic Acid, Ribonolactone, and Pyrimidine Bases
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2,3-Dideoxyribose in suitably protected form was prepared from glutamic acid and coupled with silylated cytosine to give a mixture of the α-and β-anomers of 2',3'-dideoxycitidine.The anomer ratio depended on the Lewis acid used in the coupling, with EtAlCl2 favoring the β-anomer ddC, a potent anti-HIV drug.Conjugate addition of cyanide to a 4-butenolide prepared from D-ribonolactone gave a mixture of (racemic) α- and β-3-cyanobutyrolactones.Both isomers were reduced to lactols and coupled with thymine to give α/β-anomer pairs.The α-cyano lactone, the struct ure of which was established by X-ray crystallography, afforded an authentic sample of the putative (but in fact inactive) anti-HIV substance known in AIDS research as CNT.
- Okabe, Masami,Sun, Ruen-Chu,Tam, Steve Y.-K.,Todaro, Louis J.,Coffen, David L.
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p. 4780 - 4786
(2007/10/02)
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