A Novel Approach toward the Synthesis of Chiral 2,3-Dideoxy Nucleosides and Their Carbocyclic Analogs (original) (raw)
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Tetrahedron Letters, 2000
N-Tritylated l-and d-methionine and l-glutamic acid were used to obtain novel chiral iso-dideoxynucleoside analogues incorporating a tetrahydrofuranyl or a tetrahyropyranyl ring as the pseudosugar part, and at positions 2 and 3 of the ring an hydroxyethyl group and thymine or adenine, respectively.
Stereocontrolled Syntheses of Carbocyclic C-Nucleosides and Related Compounds
The Journal of Organic Chemistry, 2001
Carbocyclic 9-deazapurine nucleosides (1-4), a spiranic pyrimidone carbocyclic compound (5), and an unusual carbocyclic isonucleoside (6) were prepared as enantiomerically pure compounds via the key intermediates 10 and 21 from 1,4-γ-ribonolactone. The key intermediate 10 was prepared by stereoselective reduction with Bu 3 SnH and then converted to carbocyclic C-ribonucleosides 1, 3, and 4. 2′,3′-Didehydro-2′,3′-dideoxycarbocyclic 9-deazainosine (2) was prepared from a 2′,3′dimesylate 17 by treatment with Li 2 Te followed by an acidic deprotection. The key bicyclic intermediate 21 was prepared from a diol 20 by an intramolecular cyclization using CHI 3-Ph 3 Pimidazole and converted to the spiranic compound 5 and an olefinic nucleoside 6 by the construction of the heterocyclic moiety followed by deprotection.
Arkivoc, 2004
Synthesis of enantiomerically pure carbocyclic nucleoside analogues 10-16 with five-, six-and seven-membered rings has been achieved starting from D-glucose derived tetracyclic isoxazolidinocarbocycle precursors 1-3. Cyclization of 6-chloro pyrimidine derivatives 7-9 to purine derivatives was found to be accomplished by nucleophilic displacement of 6-chloro substituent (by dimethylamino and/or methoxy groups). Apparently, hydrogen bonding between N-3 of the purine ring and a hydoxy substituent at C-2 / plays a crucial role in this transformation.
Carbohydrate Research, 2005
The dioxepanofuranose derivatives 4 and 12, obtained through the cyclization of the 3-(2-hydroxyethyl) ether of a D D-xylo-pentodialdose derivative, were appropriately functionalized and elaborated to the first examples of the new class of 3 0-O, and 5 0-O-bicyclic nucleoside analogues 9, 10, and 14 with a fused seven-membered ring. Reactions carried out through the intermediacy of the D D-xylo-pentodialdose derivative 5 yielded racemic products, while prior protection of the 4-formyl group (as in 7) before deprotection of the 1,2-hydroxyl groups led to optically active analogues.
Advances in the enantioselective synthesis of carbocyclic nucleosides
Chemical Society Reviews, 2013
Carbocyclic nucleosides are nucleoside analogues in which the furanosidic moiety has been replaced by a carbocycle. Several members of this family have been isolated from natural sources and include a 5-membered ring carbocycle. The aim of this review is to examine critically the different methodologies for the enantioselective construction of 3-to 6-membered rings, with a particular focus on 5-membered rings and their modifications. The procedures for bonding the heterocyclic moiety and the carbohydrate are treated separately. The methods for synthesising the carbocyclic moiety mainly focus on the construction of the cycle, although precise details about the functionalisation are provided in some cases. The selected methods aim to provide an overview of the synthesis of carbocycles related to the synthesis of carbocyclic nucleosides. The methods of synthesis of 5-membered rings are classified into two types: methods in which the cyclopentane ring is formed by ring closing reactions (CQC and C-C formation) and methods that start from preformed 5-membered rings, based mainly on cycloaddition reactions. With respect to the methods of synthesis of 3-, 4-and 6-membered ring carbocyclic nucleosides, a selection of the more relevant enantioselective procedures is presented in a systematic manner.
Photochemical Synthesis of Nucleoside Analogues from Cyclobutanones: Bicyclic and Isonucleosides
Molecules, 2010
The preparation of two nucleoside analogues are reported. Both syntheses involve a key photochemical ring-expansion of cyclobutanones to an oxacarbene and its subsequent scavenging by 6-chloropurine. The synthesis of a bicyclic (locked) purine starts from a oxabicycloheptanone with a hydroxymethyl pendant. The preparation of an isonucleoside uses a cyclobutanone with an α-substituted 6-chloropurine. Irradiation of the latter produces an isonucleoside and acyclic nucleoside analogues.
CHEMICAL & PHARMACEUTICAL BULLETIN, 2003
Six new carbocyclic nucleosides were prepared by constructing a purine base (in compounds 9-11) or pyrimidine base (in 6-8) on the amino groups of (؎)-(1b b,2a a,4b b)-4-amino-1,2-cyclopentanedimethanol (4) and (؎)-(1b b,3a a,4b b)-4-amino-1,3-cyclopentanedimethanol (5), and their activities against a variety of viruses and tumour cell lines were determined.