Solvent‐Free Conversion of Alcohols to Alkyl Iodides and One‐Pot Elaborations Thereof

Traboni, Serena; Bedini, Emiliano; Iadonisi, Alfonso

doi:10.1002/slct.201800130

Cited by 12 publications

(6 citation statements)

References 95 publications

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“…Coupling with 1,2- O -isopropylidene glycerol by trichloroacetimidate methodology gave 3- O -(2′,3′,4′,6′-tetra-acetyl)-β- d -glucosyl-glycerol that was after derivatized by stearoyl groups to obtain the key intermediate 1,2-distearoyl-3- O -β- d -glucosyl glycerol. , In the original work (route A of Scheme ), , sulfonation at carbon-6′ of glucose was achieved by multiple steps of protection and deprotection that affected negatively the overall synthetic yield. In order to overtake this issue, we tested the direct sulfonation of the 6′-carbon through an iodinate derivative in agreement with Traboni and co-workers …”

Section: Resultsmentioning

confidence: 93%

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Diasteroselective Colloidal Self-Assembly Affects the Immunological Response of the Molecular Adjuvant Sulfavant

et al. 2019

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Adjuvants are components of vaccine that enhance the specific immune response against co-inoculated antigens. Recently, we reported the characterization of a synthetic sulfolipid named Sulfavant A ( 1 ) as a promising candidate of a novel class of molecular adjuvants based on the sulfoquinovosyl-diacylglycerol skeleton. Here, we report an improved synthesis of the sulfolipid scaffold, as well as the preparation of two analogs named Sulfavant-S ( 2 ) and Sulfavant-R ( 3 ) with enhanced property to modulate master immune targets such as human dendritic cells (DCs). According to the present approach, synthesis of 1 is reduced from 14 to 11 steps with nearly triplication of the overall yield (11%). The new members 2 and 3 elicit DC maturation at a concentration of 10 nM, which is 1000 times more potent than the parent molecule 1 . Analysis of dynamic light scattering indicates self-assembly of Sulfavants and formation of colloidal particles with a small hydrodynamic radius (50 nm) for the epimers 2 and 3 and a larger radius (150 nm) for 1 . The colloidal aggregates are responsible for the bell-shaped dose–response curve of these products. We conclude that the particle size also affects the equilibrium with free monomers, thus determining the effective concentration of the sulfolipid molecule at the cellular targets and the different immunological efficacy of 1–3 . Sulfavants ( 1–3 ) do not show in vitro cytotoxicity at concentrations 10 5 higher than the dose that triggers maximal immune response, thus predicting a low level of toxicological risk in their formulation in vaccines.

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Section: Resultsmentioning

confidence: 93%

“…In order to overtake this issue, we tested the direct sulfonation of the 6′-carbon through an iodinate derivative in agreement with Traboni and co-workers. 20…”

Section: Resultsmentioning

confidence: 99%

Diasteroselective Colloidal Self-Assembly Affects the Immunological Response of the Molecular Adjuvant Sulfavant

et al. 2019

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“…Preparation of the glucosyl-trichloroacetimidate donor under strictly anhydrous conditions allowed the reduction of the amount of trichloroacetonitrile reagent (from 10 to 3 equiv) with consequent lower costs and almost quantitative conversion into 1,2- O -isopropylidene-3- O -β-(2′,3′,4′,6′-tetra- O -acetyl)- d -glucosylglycerol ( 8 ). The subsequent Zemplén deacetylation (MeO – Na + /MeOH) led to the key intermediate 4 that was directly functionalized on carbon 6′ by consecutive iodination and thioacetylation. , It is worth noting that the scaling up of the methodology allowed the use of a much lower excess of lutidine in the iodination step as an additional improvement with respect to the previous synthesis. The opening of glycerol acetonide by Lewis acid, followed by DCC-based condensation with a slight excess of stearic acid gave thioacetate 12 .…”

Section: Resultsmentioning

confidence: 99%

Short Gram-Scale Synthesis of Sulfavant A

Ziaco

Fioretto

Nuzzo³

et al. 2020

Org. Process Res. Dev.

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Recently, we reported the promising activity of a novel class of sulfoquinovosyl-diacylglycerols named Sulfavants as molecular vaccine adjuvants. Herein, we describe a modified and improved chemical synthesis of the lead product Sulfavant A (1), with the aim to produce from milligrams to 10 g of the pure compound that is necessary for the preclinical development. Starting from the versatile synthesis based on the trichloroacetimidate methodology, up-scaled preparation of Sulfavant A (1) was achieved in 11 steps by elimination and modification of those reactions that negatively affected the overall yield by the previous procedure. The novel strategy gave 17% overall yield of the target compound 1 and also paved the way for the gram-scale preparation of a wide range of other charged and neutral glycoglycerolipids.

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“…Besides reactions concerning protecting-group chemistry, other solvent-free protocols were developed for the halogenation of carbohydrates, a process allowing the functionalization with useful leaving groups. The combination of a moderate excesses of iodine, triphenyl phosphine, and lutidine proved useful for the selective iodination of primary alcohols of carbohydrates (for an example, see the first step of Scheme 11) [63]. Iodinated products thus obtained can be further elaborated in situ through solvent-free processes.…”

Section: Solvent-free Halogenation Of Saccharide Substratesmentioning

confidence: 99%

Solvent-Free Approaches in Carbohydrate Synthetic Chemistry: Role of Catalysis in Reactivity and Selectivity

et al. 2020

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Owing to their abundance in biomass and availability at a low cost, carbohydrates are very useful precursors for products of interest in a broad range of scientific applications. For example, they can be either converted into basic chemicals or used as chiral precursors for the synthesis of potentially bioactive molecules, even including nonsaccharide targets; in addition, there is also a broad interest toward the potential of synthetic sugar-containing structures in the field of functional materials. Synthetic elaboration of carbohydrates, in both the selective modification of functional groups and the assembly of oligomeric structures, is not trivial and often entails experimentally demanding approaches practiced by specialized groups. Over the last years, a large number of solvent-free synthetic methods have appeared in the literature, often being endowed with several advantages such as greenness, experimental simplicity, and a larger scope than analogous reactions in solution. Most of these methods are catalytically promoted, and the catalyst often plays a key role in the selectivity associated with the process. This review aims to describe the significant recent contributions in the solvent-free synthetic chemistry of carbohydrates, devoting a special critical focus on both the mechanistic role of the catalysts employed and the differences evidenced so far with corresponding methods in solution.

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Solvent‐Free Conversion of Alcohols to Alkyl Iodides and One‐Pot Elaborations Thereof

Cited by 12 publications

References 95 publications

Diasteroselective Colloidal Self-Assembly Affects the Immunological Response of the Molecular Adjuvant Sulfavant

Diasteroselective Colloidal Self-Assembly Affects the Immunological Response of the Molecular Adjuvant Sulfavant

Short Gram-Scale Synthesis of Sulfavant A

Solvent-Free Approaches in Carbohydrate Synthetic Chemistry: Role of Catalysis in Reactivity and Selectivity

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