Syntheses with Partially Benzylated Sugars. III.¹ A Simple Pathway to a “cis- Nucleoside,” 9-β-D-Arabinofuranosyladenine (Spongoadenosine)

Abstract

V O L . 28 ml.) was then added and the mutarotation observed at 20'. The specific rotations and first-order rate constants are given in Table 111. Based on an average rate of 0.00016, the "half-life" of the reaction was 1881 min.When mutarotation had ceased, the solvent was removed in vacuo to give a sirup which ww crystallized from ethyl acetatepentane. The short, colorless needles thus obtained were recrystallized from the same solvent mixture 0.2 g. (660/,), m.p. 133-135", [~I~O D +145.4" -* +102.5" (methanol, c 1.27). G. McCann.These values agree with those reported earlier in this paper for 2- 0-benzoyl-8-L-arabinopyranose.Acknowledgment.-We are indebted to Mr. Harry w . Diehl for the preparation of Some starting materials. h a l y s e s were performed by the ~~~l~~ services Unit Of this laboratory under the direction Of Mr. H. Condensation of 2,3,5-tri-O-benzyl-~-arabinofuranosyl chloride with methanol leads predominantly to methyl 2,3,5-tri-O-benzyl-p-~-arabinofuranoside. Condensation of the same halide with N-benaoyladenine and subsequent removal of the protecting groups readily gives 9-p-D-arabinofuranosyladenine, a type of glycoside which is difficultly accessible by other means.

D-Arbinose-Based Synthesis of homo-C-d4T and homo-C-thymidine

“…The chloride 24 was obtained from p-nitrobenzoates 17 by the published procedure [78] as an α:β = 95:5 mixture by 1 H 200 MHz measurement. Attempts to obtain 24 directly from 2,3,5-tri-O-benzyl-D-arabinofuranose 23 by the method of Perlin et al [79] (MsCl, sym-collidine) were negative and resulted only in black, heterogeneous mixtures, whereas triphosgene and 23 was published to yield 24 with a higher content of the unwanted β anomer (α:β = 86 :14).…”

“…[78] 17 (2.1 g, 3.7 mmol) was added to a cold (ice bath) saturated solution of HCl in CH 2 Cl 2 (50 ml). After 1 hour a slow stream of HCl was passed through the resulting heterogeneous mixture during 10 minutes, and incubation was continued for 50 minutes more at ca.…”

A One-Pot Synthesis of 1-α- And 1-β-D-Arabinofuranosyl-2-Nitroimidazoles: Synthons to the Markers of Tumor Hypoxia

“…Efforts to avoid this retention of configuration have included replacing the benzoyl protective groups with benzyl-or substituted silyl-(non-carbonylated) groups. [9] An alternative approach to synthesize b-AZA via inversion of configuration at C-2' of the corresponding b-azomycin riboside has been reported. [6] To date there have been no reports of a one pot synthesis to provide useful yields of both a-and b-arabinofuranosyl azomycin nucleosides in reasonable yields.…”

Synthesis of 1-.BETA.-D-(5-Deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (.BETA.-IAZA): A Novel Marker of Tissue Hypoxia.

“…20) This problem can often be circumvented by using a protecting group at C-2Ј that does not participate in displacement of the halide at C-1Ј (e.g. benzyl), 21) or by C-2Ј inversion of configuration of the corresponding b-ribonucleoside. 21) In the present work, the utilization of benzyl protection at C-2Ј is complicated by the reductive deblocking step, which threatens the integrity of the nitro substituent on the azomycin moiety.…”

“…benzyl), 21) or by C-2Ј inversion of configuration of the corresponding b-ribonucleoside. 21) In the present work, the utilization of benzyl protection at C-2Ј is complicated by the reductive deblocking step, which threatens the integrity of the nitro substituent on the azomycin moiety. Consequently, inversion of configuration at C-2Ј of 1-b-D-(ribofuranosyl)-2-nitroimidazole (b-AZR) was the preferred approach to the synthesis of b-IAZA.…”