A Convenient Method for C-Azanucleosides Synthesis

Metalated Heterocycles and Their Applications in Synthetic Organic Chemistry

“…2-Lithiated thiophenes have found frequent applications reacting as nucleophiles, for example, with aldehydes in the synthesis of core-modified porphyrins 62 or azanucleosides, and with ketones for the synthesis of bithiophene-containing calixpyrrole analogues, sulfur-containing heteroaromatics, angular triquinanes,38b heteroaryl-substituted zirconium complexes, or some carboranylbutenolides . There are also examples of reactions of 2-thienyllithiums with esters, amides 68 (including Weinreb amides 69 ), the carbonyl group of 2-pyrrolidinones, the Vilsmaier reagent, and carbon dioxide 72 or the regioselective synthesis of esters by addition of the organolithium 27 to cyclic carbonates such as compound 26 , which affords the corresponding ester 28 as the only isomer, used in studies on taxoids (Scheme ) …”

Addition of Lithiated 9-Deazapurine Derivatives to a Carbohydrate Cyclic Imine: Convergent Synthesis of the Aza-C-nucleoside Immucillins

“…While we have investigated several possible alternative routes to the immucillins based on literature precedents, these were either unsuccessful or proved impractical for large scale synthesis . An apparently useful synthesis of C -linked (1,4-dideoxy-1,4-imino-β- d -ribofuranosyl)heterocycles by reductive amination of 1- C -substituted d - erythro - pentose-4-uloses cannot be applied, because it has subsequently been shown to afford only products with the β- l - lyxo -configuration, that is, the 1‘,4‘ epimers of the required products. Consequently, we decided to refocus on the iminoribitol 3 as a key compound; it has the advantages of being relatively readily available and having all but one of the chiral centers in place.…”

Synthesis and Properties of C-Azalyxonucleosides

“…With the above results in hand, we reinvestigated the structures of C -azanucleosides which were reported by us previously . The C -azanucleoside bearing a 2-benzofuryl group as the base moiety was acetylated to give 6a as good crystals.…”

“…To our best knowledge, such types of nucleosides have been known in some reports, but their chemistry has not been investigated in detail. Thus, we intended to synthesize the C -azanucleosides in gram quantities and by a simple method . Here we report the following results: (1) stereoselective synthesis of C -azalyxonucleosides starting from O -( tert -butyldimethylsilyl)-2,3- O -isopropylidene- d -ribo-furanose 1 via a sequential procedure by the addition of metal salts of uracil or imidazole, Swern oxidation, and reductive aminocyclization using ammonium formate and NaBH 3 CN; (2) X-ray analysis of C -azanucleosides including three C -azafuranosylnucleosides reported previously; (3) two rotational isomers of their acyl derivatives; and (4) their biological activity.…”