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The hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over a Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of the C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in the hydrodeoxygenation of other polyols to some extent but much less active in that of mono-alcohols, at higher temperature (453 K), mono-alcohols can be produced from sugar alcohols. A good total yield (59%) of pentanols can be obtained from xylitol, which is mainly converted to C2 + C3 products in the literature hydrogenolysis systems. It can be applied to the hydrodeoxygenation of other sugar alcohols to mono-alcohols with high yields as well, such as erythritol to butanols (74%) and sorbitol to hexanols (59%) with very small amounts of C-C bond cleavage products. The active site is suggested to be the Pt-WOx interfacial site, which is supported by the reaction and characterization results (TEM and XAFS). WOx/SiO2 selectively catalyzed the dehydration of xylitol to 1,4-anhydroxylitol, whereas Pt-WOx/SiO2 promoted the transformation of xylitol to pentanols with 1,3,5-pentanetriol as the main intermediate. Pre-calcination of the reused catalyst at 573 K is important to prevent coke formation and to improve the reusability.

The present document describes compounds, or pharmaceutically acceptable salt thereof, of a core formula (I) Wherein R1 includes an amino group. These compounds are particularly useful in the formulation and in vivo and ex vivo delivery of nucleic acid and protein therapeutics for preparing and implementing T cell transfection, gene editing, cancer therapies, cancer prophylactics, and in the preparation of vaccines.

Various embodiments provide STOPS? polymers that are S-antigen transport inhibiting oligonucleotide polymers, processes for making them and methods of using them to treat diseases and conditions. In some embodiments the STOPS? modified oligonucleotides include an at least partially phosphorothioated sequence of alternating A and C units having modifications as described herein. The sequence independent antiviral activity against hepatitis B of embodiments of STOPS? modified oligonucleotides, as determined by HBsAg Secretion Assay, is an EC50 that is less than 100 nM.

The large pool of naturally occurring carbohydrates with their diversity in chirality and structure led to the idea of a systematic investigation of carbohydrate based ILs. To this end, we investigated the influence of different ether groups, mainly methyl or ethyl ether, on the secondary OH groups as well as different configurations on physical properties such as melting point, thermostability and especially the influence on cell toxicity. For this investigation we chose α- and β-methyl-, β-allyl- and β-phenyl d-glucopyranose as well as four 1-deoxy-pentoses. In order to be able to classify the results, more ionic liquids with different structural motives were examined for cytotoxicity. Here, we present data that confirm the biocompatibility of such ILs consisting of naturally occurring molecules or their derivatives. The synthesized carbohydrate based ILs were tested for their suitability as additives in coatings for medical applications such as drug-eluting balloons.

The feedstocks from biomass are defined and limited by nature, but through the choice of catalyst, one may change the deoxygenation outcome. We report divergent but selective deoxygenation of sugars with triethylsilane (TESH) and two fluoroarylborane catalysts, B(C6F5)3 and B(3,5-CF3)2C6H3)3 (BAr3,5-CF3). To illustrate, persilylated 2-deoxyglucose shows exocyclic C-O bond cleavage/reduction with the less sterically congested BAr3,5-CF3, whereas endocyclic C-O bond cleavage/reduction predominates with the more Lewis acidic B(C6F5)3. Chiral furans and linear polyols can be selectively synthesized depending on the catalysts. Mechanistic studies demonstrate that the resting states of these catalysts are different.

Carbohydrate biomass represents a potentially valuable sustainable source of raw materials for chemical synthesis, but for many applications, selective deoxygenation/dehydration of the sugars present is necessary to access compounds with useful chemical and physical properties. Selective dehydration of pentose sugars to give tetrahydrofurans can be achieved by treatment of the corresponding N,N-dimethylhydrazones under acidic or basic conditions, with the two approaches showing complementary stereoselectivity. The dehydration process is readily scalable and the THF hydrazones derived from arabinose, ribose, xylose and rhamnose were converted into a range of useful fragments containing primary alcohol, ketone, carboxylic acid or amine functional groups. These compounds have potentially useful physiochemical properties making them suitable for incorporation into fragment/lead generation libraries for medicinal chemistry. It was also shown that l-arabinose hydrazone could be obtained selectively from a crude sample of hydrolysed sugar beet pulp.

The intramolecular dehydration of biomass-derived sugar alcohols d-sorbitol, d-mannitol, galactitol, xylitol, ribitol, l-arabitol, erythritol, l-threitol, and dl-threitol was investigated in high-temperature water at 523-573 K without the addition of any acid catalysts. d-Sorbitol and d-mannitol were dehydrated into isosorbide and isomannide, respectively, as dianhydrohexitol products. Galactitol was dehydrated into anhydrogalactitols; however, the anhydrogalactitols could not be dehydrated into dianhydrogalactitol products because of the orientation of the hydroxyl groups at the C-3 and C-6 positions. Pentitols such as xylitol, ribitol, and l-arabitol were dehydrated into anhydropentitols. The dehydration rates of the pentitols containing hydroxyl groups in the trans form, which remained as hydroxyl groups in the product tetrahydrofuran, were larger than those containing hydroxyl groups in the cis form because of the structural hindrance caused by the hydroxyl groups in the cis form during the dehydration process. In the case of the tetritols, the dehydration of erythritol was slower than that of threitol, which could also be explained by the structural hindrance of the hydroxyl groups. The dehydration of l-threitol was faster than that of dl-threitol, which implies that molecular clusters were formed by hydrogen bonding between the sugar alcohols in water, which could be an important factor that affects the dehydration process.

The aqueous-phase hydrogenolysis of xylitol into glycols over Ru/C was performed in the presence and absence of a wide range of concentrations of Ca(OH)2 to investigate the reaction pathway. Without base, epimerization and cascade decarbonylation were the predominant reactions with high selectivities to C5 and C4 alditols and light alkanes at full conversion. Glycol production was obtained by the addition of Ca(OH)2 to promote the retro-aldol reaction. It competed with reactions without base and became the main reaction for a OH?/ xylitol molar ratio Rmol(OH/xylitol) of 0.13, and high selectivities to glycols (56 %) and glycerol (16 %) were observed. However, lactate was a byproduct at up to 27 % with a high base amount (Rmol(OH/xylitol)=0.68). Bifunctional Ru/metal oxide/C catalysts (metal: Zn, Sn, Mn, Sr, W) were synthesized and were able to cleave the C?C bond into glycols without a base promoter. The 3.1 wt %Ru/MnO(4.5 %)/C catalyst was the most active (220 h?1) with reasonable selectivity to glycols (22 %) and glycerol (10 %) and a low production of lactate (1 %). Nevertheless, metal oxide leaching of the catalyst was observed likely because of the production of traces of lactate.

A series of novel xylitan derivatives derived from xylitol were synthesized using operationally simple procedures. A xylitan acetonide was the key intermediate used to prepare benzoate, arylsulfonate esters and 1,2,3-Triazole derivatives of xylitan. These compounds were evaluated for their in vitro anti-Trypanosoma cruzi activity against trypomastigote and amastigote forms of the parasite in T. cruzi-infected cell lineages. Benznidazole was used as positive control against T. cruzi and cytotoxicity was determined in mammalian L929 cells. The arylsulfonate xylitan derivative bearing a nitro group displayed the best activity of all the compounds tested, and was slightly more potent than the reference drug benznidazole. The importance of the isopropylidene ketal moiety was established and the greater lipophilicity of these compounds suggests enhancement in cell penetration.

L-Arabinose is an abundant resource available as a waste product of the sugar beet industry. Through use of a hydrazone-based strategy, L-arabinose was selectively dehydrated to form a chiral tetrahydrofuran on a multi-gram scale without the need for protecting groups. This approach was extended to other biomass-derived reducing sugars and the mechanism of the key cyclization investigated. This methodology was applied to the synthesis of a range of functionalized chiral tetrahydrofurans, as well as a formal synthesis of 3R-3-hydroxymuscarine.

Using a combined theoretical and experimental strategy, the heats of hydrogenation of the nucleotide bases uracil, thymine, cytosine, adenine, and guanine have been determined. The most easily hydrogenated base is uracil, followed by thymine and cytosine. Comparison of these hydrogenation enthalpies with those of ketones and aldehydes derived from sugar models indicates the possibility of near-thermoneutral hydrogen transfer between uracil and the sugar phosphate backbone in oligonucleotides. (Figure Presented)

A practical process for the preparation of anhydroalditols from commodity carbohydrates has been described. Reductive cleavage of the glycosidic linkage in perallylated carbohydrates with triethylsilane gave the protected anhydroalditols, which were then deallylated using a PdCl2-CuCl2-Activated Charcoal system. Valuable anhydroalditols, such as 1,5-anhydro-D-glucitol, 1,5-anhydro-D-mannitol, 2,5-anhydro-D-glucitol, 2,5-anhydro-D-mannitol and 1,4-anhydro-Dribitol, were prepared in high yields and purity from carbohydrates, such as glucose, mannose, ribose, sucrose, cellulose, starch and levan.

To elucidate the role of the sugar moiety in the two natural nucleotides of the 3′-overhang region of small interfering RNA (siRNA), we synthesized siRNAs that incorporated two abasic nucleosides, 1-deoxy-d-ribofuranose (R H). We improved the method for preparing an O-protected abasic nucleoside, 1-deoxy-2,3,5-tri-O-benzoyl-β-d-ribofuranose, via the reductive cleavage of the anomeric position of 1-O-acetyl-2,3,5-tri-O-benzoyl-β-d- ribofuranose. To incorporate RH into oligonucleotides by the standard phosphoramidite solid phase method, RH was converted into its phosphoramidite derivative and the solid support linked to a controlled pore glass resin. Chemically modified RNAs possessing RH at the 3′-overhang region were easily prepared in good yields. siRNAs containing RH showed moderate nuclease-resistance and a desirable knockdown effect.

It is an object of the instant invention to provide a method for the rapid evaluation of novel sugar modifications to be used in siRNA synthesis including the rapid evaluation of chemical modification patterns within the siRNA to effectuate increased stability and ultimately increased efficacy of a siRNA therapeutic. It is a further object of the instant invention to provide novel nucleosides useful for siRNA therapy.

The present disclosure relates to the preparation of ketal compounds from anhydropentitols and oxocarboxylates; derivatives, homopolymers, and copolymers thereof; and various compositions, formulations, and articles derived therefrom.

Dehydration of D-arabinitol, ribitol, and xylitol at high temperature in the presence of molecular sieves without solvent in an argon atmosphere is described. Products arising after the dehydration-cyclization (cyclodehydration) reaction with retention or inversion of the configuration of asymmetric carbon atoms, were observed. Complete analytical separations of exhaustively O-acetylated reaction products were achieved by means of GC. The chemical structures of the compounds obtained were assigned using co-injection with standards. Copyright

The syntheses have been developed for quaternary N-(1,4-anhydro-5-deoxy-2, 3-O-isopropylidene-d,l-ribitol-5-yl)ammonium salts derived from five aromatic amines, pyridine, 2-methylpyridine, 3-carbamoylpyridine, 4-(N,N-dimethylamino) pyridine, and quinoline, as well as two tertiary aliphatic amines, trimethylamine and triethylamine. Reactions of 1,4-anhydro-2,3-O-isopropylidene- 5-O-tosyl-d,l-ribitol with tri-n-propylamine and tri-n-butylamine were unsuccessful. The products were identified on the basis of their 1H and 13C NMR spectra. The structure of N-(1,4-anhydro-5-deoxy-2,3-O- isopropylidene-d,l-ribitol-5-yl)trimethylammonium tosylate was additionally elucidated by X-ray diffractometry.

The synthesis and directed dihydroxylation of a range of cyclic alkenes was investigated. Both homoallylic alcohols and homoallylic trihaloacetamides were found to be efficient directing groups, giving rise to good to excellent levels of remote asymmetric induction with OsO4-TMEDA. Interestingly, in all cases examined, trifluoroacetamides were found to be superior to trichloroacetamides as directing groups and an argument is presented which rationalises this observation.

Six different ribonucleoside phosphoramidites with fluorobenzenes or fluorobenzimidazoles as base analogues, one abasic site, and inosine were synthesized and incorporated into oligoribonucleotides. The oligomers were investigated by means of UV and CD spectroscopy to assess the contribution of H-bonding, base stacking, and solvation to the stability of the RNA duplex. CD Spectra show that the incorporation of modified nucleosides does not lead to changes in the structure of RNA. The T(m) differences determined are based on changes in base stacking and solvation. Individual contributions of base stacking and solvation of the modified nucleosides could be determined. In fluorobenzene·fluorobenzimidazole-modified base pairs, a duplex-stabilizing force was found that points to a weak F ··· H H-bond.

The 3'-β-C-branched anhydrohexitol nucleosides have been conveniently synthesised starting from commercially available D-ribose following the reaction sequence: (i) conversion of protected pentofuranose sugar to the corresponding hexopyranosyl nitrosugar (ii) addition of the conjugate base of nitrosugar to formaldehyde to obtain C-branched nitro sugar (iii) removal of nitro group by n-tributyltin hydride treatment and (iv) Mitsunobu type alkylation to build up the nucleobase.

A series of 3'-β-C-branched anhydromannitol nucleosides were conveniently synthesized starting from commercially available D-ribose. The reaction sequences were: (i) conversion of the protected pentofluranose to the corresponding nitrohexopyranose; (ii) addition of the conjugated base of the nitrosugar to formaldehyde; (iii) removal of the nitro group by n-tributyltin hydride treatment and (iv) Mitsunobu type alkylation to introduce the nucleobase. The conformation of intermediates and final compounds were deduced from NMR analysis. The thymine congener showed potent activity against herpes simplex virus (HSV).

Several per-O-methylated monosaccharides and polysaccharides were used as models in an attempt to identify more convenient reagents for accomplishing reductive cleavage of glycosidic linkages. Included in the model studies were methyl α- and β-D-glucopyranoside, methyl α- and β-D-mannopyranoside, and methyl α- and β-D-ribofuranoside. These studies led to the identification of a new promoter, butyltin trichloride, for carrying out reductive cleavage when borane-methyl sulfide complex was used as the reducing agent. These reagents were found to accomplish the reductive cleavage of per-O-methylated amylose, cellulose, and pullulan to give only the expected derivatives of 1,5-anhydro-D-glucitol. These reagents also accomplished reductive cleavage of per-O-methylated inulin to give only the expected derivatives of 2,5-anhydro-D-mannitol and 2,5-anhydro-D-glucitol. Reductive cleavage using these reagents is easy to perform, and subsequent acetylation of the products is readily accomplished in situ.

1-deoxy-1-dimethylarsinoylribitol-5-sulfate has been synthesised from ribitol and shown to be identical with a natural constituent of Chondria crassicaulis and other red algae, some of which contribute to the human diet in Japan.

Approaches to 1,4-anhydro-3-azido-2,3-dideoxy-2-[3,4-dihydro-2,4-dioxo-5- methyl-1(2H)-pyrimidinyl]-D-arabinitol, and the related uracil derivative, have been developed. These conceptually new, optically active analogs of AZT, derived from 1,4-anhydro-D-ribitol, are among the first examples of regioisomeric analogs of AZT.

Approaches to representative examples of 3'-isomeric dideoxynucleosides with 2'(S),3'(R) and 2'(R),3'(S) absolute stereochemistry have been developed.These are among the first cases of isomeric dideoxynucleosides with the base moiety at the 3'-position.The chemistry developed has generality and can be applied to the synthesis of other related isomeric nucleosides.

A simple procedure, which consists of direct heating of pyridinium chloride and the starting material, is described for the dehydration of alditols. Anhydroalditols, of great interest for various applications, are thus obtained, and the selectivity of the reaction is discussed. Some selective protections for further uses of these products are studied.

D-Ribono-1,4-lactone, after acetalation, tritylation, and reduction, leads to a cyclization compound which gave with tosyl chloride 1,4-anhydro-2,3-O-isopropylidene-5-O-trityl-D-ribitol.The latter was transformed (acid hydrolysis, periodate oxidation, reduction, tritylation, and tosylation) into a ditosylated derivative 16, which was cyclized into morpholines by the action of primary amines.Acid hydrolysis, followed by acetylation, gives the (2S)-acetoxymethyl-4-isopropyltetrahydro-1,4-oxazine (21).A similar sequence has been applied to D-gulonolactone to give access to oxazines 33, 34, and 35. Keywords: Synthesis; D-Ribono-1,4-lactone; D-Gulono-1,4-lactone; Morpholine derivatives

Approaches to the enantiospecific syntheses of shikimic acid and immunoactivator FR 900483 utilising Rabbit Muscle Aldolase condensations have been described.

The conformational characteristics of abasic 1-deoxy sugars 1, 2, and 3 and pentofuranose moieties in 2′,3′-dideoxy-[ddA (6), ddG (7), ddC (8)], 2′-deoxy-[dA (9), dG (10), dC (11)], and ribo-β-D-nucleosides [Ade (12), Gua (13), Cyt (14)] were established through the analysis of vicinal proton-proton coupling constants extracted from their 500-MHz 1H-NMR spectra recorded at 20 K intervals in the temperature range from 278 to 358 K in D2O solution. Two novel deuterated analogues of (S)-tetrahydrofurfuryl alcohol (1), 2-(S)-(hydroxymethyl)-4-(R)-deuteriotetrahydrofuran (4) and 2-(S)-(hydroxymethyl)-3-(S)-deuteriotetrahydrofuran (5), have enabled unequivocal assignment of the complex nine-spin system in its 1H-NMR spectrum. The van't Hoff plots of (ln(XS/XN)] as a function of 1/T gave ΔH° and ΔS° values of pseudorotational equilibrium in pentofuranoses 1-3 and pentofuranose moieties in nucleosides 6-14. The values of ΔH° were dissected into various stereoelectronic effects (gauche versus anomeric effects) of exocyclic substituents on the pentofuranose moiety. Clearly, the gauche effect of the O4′-C4′-C3′-O3′ fragment drives the pseudorotational equilibrium to the S-type conformations, while the gauche effect of the O4′-C1′-C2′-O2′ fragment pushes the pseudorotational equilibrium to the N. These gauche effects are the strongest factors responsible for driving the N ? S pseudorotational equilibrium. The strength of the gauche effect of the O4′-C4′-C3′-O3′ fragment in abasic sugars 1-3 is further tuned by the presence of a heterocyclic base at C1′ in nucleosides 6-14. The relatively weaker anomeric effect of the heterocyclic base drives the N ? S equilibrium to the N. The assessment of the relative strengths of the anomeric effects in 2′,3′-dideoxy, 2′-deoxy-, and ribo-β-D-nucleosides has shown that the anomeric effect of the cytosine base is stronger than the anomeric effect of the adenine or guanine base. The experimental data suggest that the anomeric effect is considerably reduced as O4′ experiences the electron-withdrawing effect(s) of 2′(3′)-hydroxyls. The differences in the conformational preferences found in purine and pyrimidine ribonucleosides were additionally attributed to the distinct relative strength of the gauche effect of the N-C1′-C2′-O2′ fragment. The preference for the gauche orientation of the N-C1′-C2′-O2′ fragment and therefore S-type sugar conformation is affected by the nature of the purine or pyrimidine glycosyl nitrogen atom.

Methanesulfonyl chloride in N,N-dimethylformamide transformed unprotected D-arabinitol into its 1,5-dichloro derivative in 50percent yield.Other pentitols also reacted to give the corresponding 1,5-dichloropentitols, but with lower yields.The structures of the products were determined by n.m.r. spectroscopy.

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Efforts to expedite production of anhydroalditols have led to a new, efficient synthesis of these compounds from alkyl glycosides.Silylation of the glycoside followed by reductive cleavage in the presence of triethylsilane and trimethylsilyl trifluoromethanesulfonate were carried out in the same reaction flask.Subsequent aqueous workup gave excellent yields of anhydroalditol(s).In some cases ring contraction was observed, but the use of bulkier silyl protecting groups gave greater yields of the expected product.This method was also shown to be an efficient means to prepare allyl C-glycosides, without any independent protecting or activating step, by simply replacing triethylsilane with allyltrimethylsilane in the synthetic scheme.

Using D-(-)-ribose as chiral starting material, we have prepared 1-deoxy-D-ribofuranose by a novel route, and then employed both compounds as precursors of the dioxaprostacyclin analogues (2).

The products of dehydration of pentitols in aqueous sulfuric acid have been studied by g.l.c.-m.s.Four isomeric 1,4-anhydropentitols were formed from D-arabinitol, but only two from xylitol and ribitol.The number of products could only be explained by assuming inversion of configuration at C-2 or C-4 during 1,4- or 2,5-cyclisation reactions.No product which involved inversion of configuration at C-3 was observed.Various mechanisms of isomerisation are considered.