1.Synthesis of methyl 2-O-allyl-(and 3-O-allyl)-5-O-benzyl-beta-D- ribofuranoside.
Desai T1, Gigg J, Gigg R. Carbohydr Res. 1996 Jan 11;280(2):209-21.
D-Ribose was converted into methyl 5-O-benzyl-beta-D-ribofuranoside and this, on tin-mediated allylation, gave a mixture of the 2-O-allyl and 3-O-allyl derivatives which were separated by chromatography. The more polar isomer was characterised as the 3-O-allyl derivative after conversion via 3-O-allyl-5-O-benzyl-1,2-O-isopropylidene-alpha-D-ribofuranose (which was also synthesised from 3-O-allyl-1,2:5,6-di-O-isopropylidene-alpha-D-allofuranose) into the known 5-O-benzyl-1,2-O-isopropylidene-alpha-D-ribofuranose. Methyl 3-O-allyl-5-O-benzyl-beta-D-ribofuranoside was converted into methyl 2-O-allyl-5-O-benzyl-beta-D-ribofuranoside via methyl 2-O-allyl-5-O-benzyl-3-O-(prop-1-enyl)-beta-D-ribofuranoside.
2.Synthesis and biological evaluation of 3'-C-ethynyl and 3'-C-(1,4-disubstituted-1,2,3-triazolo) double-headed pyranonucleosides.
Kiritsis C1, Manta S, Papasotiriou I, Coutouli-Argyropoulou E, Trakossas S, Balzarini J, Komiotis D. Med Chem. 2012 May;8(3):320-9.
A novel series of 3'-C-ethynyl and 3'-C-(1,4-disubstituted-1,2,3-triazolo) double-headed pyranonucleosides has been designed and synthesized. Reaction of 3-keto glucoside 1 with ethynyl magnesium bromide gave the desired precursor 3-C-ethynyl-1,2:5,6-di-O-isopropylidene-α-D-allofuranose (2). Hydrolysis followed by acetylation led to the 1,2,4,6-tetra-O-acetyl-3-C-ethynyl-β-D-allopyranose (3). Compound 3 was condensed with silylated 5-fluorouracil, uracil, thymine, N4-benzoylcytosine and N6-benzoyladenine, respectively and deacetylated to afford the target 1-(3'-C-ethynyl-β-D-allopyranosyl)nucleosides 5a-c,f,g. Copper-Catalyzed Azide-Alkyne Cycloaddition (CuAAC) reaction was utilized to couple the 3'-C-ethynyl pyranonucleoside derivatives with azidoethyl adenine, 5-fluorouracil and thymine, respectively to afford novel triazole double-headed nucleoside analogs 8a-h. 3'-C-Ethynyl pyranonucleosides and the new double-headed analogues were evaluated for their antiviral and cytostatic activities.
3.[Synthese of 1-(5-deoxy-beta-D-ribo-hexofuranosyl)cytosine and 1-(2,5-dideoxy-beta-D-erythro-hexofuranosyl)cytosine, and their phosphates. Specificity of an mammalian (rat) ribonucleotide-reductase].
David S, de Sennyey G. Carbohydr Res. 1979 Dec;77:79-97.
Mild, acidic hydrolysis of 3-O-benzoyl-1,2,:5,6-di-O-isopropylidene-alpha-D-allofuranose gave a diol that was selectively benzoylated at O-6 in high yield by intermediate conversion to the stannylene derivative. The 3,6-dibenzoate was converted to the 5-O-tosyl derivative and thence to a mixture of iodides, which were reduced with tributylstannane to 3,6-di-O-benzoyl-1,2-O-isopropylidene-alpha-D-ribo-hexofuranose (6). Acetolysis gave an anomeric mixture of diacetates, which, when treated with N-acetylbis(trimethylsilyl)cytosine gave the protected nucleoside, which was deprotected to free "homocytidine", 1-(5-deoxy-beta-D-ribo-hexofuranosyl)cytosine (11), by alklaine methanolysis. This was N-acetylated and then treated with acetone to give a protected nucleoside, which was labelled by oxidation to the aldehyde, reduction with sodium borotritide, and deprotection. Acidic methanolysis of 6 gave a mixture of methyl 2,6- and 3,6-di-O-benzoylfuranosides, the hydroxyl groups of which were treated by the tetrachloromethane-triphenylphosphine reagent to give the 2-chloro-2-deoxy (21) and 3-chloro-3-deoxy derivatives.
4.Sequential ring-closing metathesis and nitrone cycloaddition on glucose-derived substrates: a divergent approach to analogues of spiroannulated carbanucleosides and conformationally locked nucleosides.
Sahabuddin S1, Roy A, Drew MG, Roy BG, Achari B, Mandal SB. J Org Chem. 2006 Aug 4;71(16):5980-92.
The carbohydrate-derived substrate 3-C-allyl-1,2:5,6-di-O-isopropylidene-alpha-D-allofuranose was judiciously manipulated for preparing suitable synthons, which could be converted to a variety of isoxazolidino-spirocycles and -tricycles through the application of ring-closing metathesis (RCM) and intramolecular nitrone cycloaddition (INC) reactions. Cleavage of the isoxazolidine rings of some of these derivatives by transfer hydrogenolysis followed by coupling of the generated amino functionalities with 5-amino-4,6-dichloropyrimidine furnished the corresponding chloropyrimidine nucleosides, which were elaborated to spiroannulated carbanucleosides and conformationally locked bicyclo[2.2.1]heptane/oxa-bicyclo[3.2.1]octane nucleosides. However, use of higher temperature for the cyclization of one of the chloropyrimidines led to the dimethylaminopurine analogue as a sole product, formed via nucleophilic displacement of the chloro group by dimethylamine generated from DMF.