Furandicarboxylate Polyesters: A Comprehensive ADMET Study of a Novel Class of Furan-Based α,ω-Diene Monomers.

The present research article delves into the preparation of a new class of bio-based polyesters from α,ω-diene furandicarboxylate monomers. In particular, it exploits the use of acyclic diene metathesis polymerisation (ADMET) on 2,5-furandicarboxylic acid (FDCA)-derived compounds. First, a library of furan-based α,ω-diene monomers was prepared via acid- or base-catalyzed transesterification of 2,5-furandicarboxylic acid dimethyl ester (FDME) with commercially available alcohols incorporating terminal olefins, i.

Green Synthesis of UV-Reactive Polycarbonates from Levoglucosenone and 5-Hydroxymethyl Furfural.

This study focuses on the synthesis of fully renewable polycarbonates (PCs) starting from cellulose-based platform molecules levoglucosenone (LGO) and 2,5-bis(hydroxymethyl)furan (BHMF). These unique bio-based PCs are obtained through the reaction of a citronellol-containing triol (Triol-citro) derived from LGO, with a dimethyl carbonate derivative of BHMF (BHMF-DC). Solvent-free polymerizations are targeted to minimize waste generation and promote an eco-friendly approach with a favorable environmental factor (E-factor).

Reaction Pathways in Carbonates and Esters.

This review reports on the competition/collaboration among intertwined base-catalyzed acyl cleavage bimolecular mechanism (B 2)/base-catalyzed alkyl cleavage bimolecular mechanism (B 2) or the related acid catalyzed mechanisms A 2/A 2 and A 1 concerning Carbonates chemistry also in comparison with Esters reactivity. A consistent analysis of the experimental data so far available in the literature led to proposing a theoretical Model outlining the differences in energy profiles among the above-mentioned reaction mechanisms. The reactions involving Carbonates are so tightly interconnected that the formation of the final product is driven by a precise not interfering sequence of B 2-B 2 (or A 2-A 2) mechanisms.

Multigram Synthesis of Pure HMF and BHMF.

5-Hydroxymethylfurfural (HMF) is a bio-based platform chemical that can be used as a building block to produce several compounds with diverse applications. Even though HMF synthesis holds promise for a greener future, the current state of technology and the high production cost limit its competitiveness on an industrial scale. In this prospect, we have developed a multigram-scale procedure for HMF by reacting d-fructose with Purolite CT275DR-an acidic resin-in a dimethyl carbonate (DMC)/tetraethyl ammonium bromide (TEAB) biphasic system.

Sustainable Hyperbranched Functional Materials via Green Polymerization of Readily Accessible Levoglucosenone-Derived Monomers.

The homopolymerization in basic conditions of the recently reported bis(γ-lactone), 2H-HBO-HBO, is herein described for the first time. The solvent-free polymerization of this pentafunctional levoglucosenone (LGO) derivative affords fully renewable poly(vinyl-ether lactone) copolymers with a highly hyperbranched structure. This investigation stems from the polycondensation trials between 2H-HBO-HBO and di(methyl carbonate) isosorbide (DCI) that fails to give the anticipated polycarbonates.

Dialkyl Carbonates in the Green Synthesis of Heterocycles.

This review focuses on the use of dialkyl carbonates (DACs) as green reagents and solvents for the synthesis of several 5- and 6-membered heterocycles including: tetrahydrofuran and furan systems, pyrrolidines, indolines, isoindolines, 1,4-dioxanes, piperidines, and cyclic carbamates. Depending on the heterocycle investigated, the synthetic approach used was different. Tetrahydrofuran systems, pyrrolidines, indolines, isoindoline, and 1,4-dioxanes were synthesized using dimethyl carbonate (DMC) as sacrificial molecule (B2/B2 mechanism).

β-Aminocarbonates in Regioselective and Ring Expansion Reactions.

The reactivity of β-aminocarbonates as anisotropic electrophiles has been investigated with several phenols. Products distribution shows that the regioselectivity of the anchimerically driven alkylation reaction depends on the nucleophiles. The results suggest that in the presence of nucleophiles that are also good leaving groups, the reaction takes place under thermodynamic control favoring the attack on the most sterically hindered carbon of the cyclic aziridinium intermediate.

Isosorbide and dimethyl carbonate: a green match.

In this review the reactivity of the bio-based platform compounds D-sorbitol and isosorbide with green reagents and solvent dimethyl carbonate (DMC) is reported. Dehydration of D-sorbitol via DMC in the presence of catalytic amounts of base is an efficient and viable process for the preparation of the industrially relevant anhydro sugar isosorbide. This procedure is "chlorine-free", one-pot, environmental friendly and high yielding.

Azacrown Ethers from Mustard Carbonate Analogues.

Polycondensation of a nitrogen mustard carbonate analogue with aromatic diols under dilution conditions affords a series of azacrown ethers previously not easily accessible as they require multistep synthesis including protection, purification, cyclization and methylation. This novel synthesis relies upon the anchimeric effect of the nitrogen mustard carbonate and it does not require the use of any base.

Synthesis of five-membered cyclic ethers by reaction of 1,4-diols with dimethyl carbonate.

The reaction of 1,4-diols with dimethyl carbonate in the presence of a base led to selective and high-yielding syntheses of related five-membered cyclic ethers. This synthetic pathway has the potential for a wide range of applications. Distinctive cyclic ethers and industrially relevant compounds were synthesized in quantitative yield.

The stability of imine-containing dynamic [2]rotaxanes to hydrolysis.

Large amounts (>100 mol equivalents) of water are required to effect by hydrolysis the partial disassembly of the rings from the dumbbell components of two dynamic [2]rotaxanes. The two dynamic [2]rotaxanes are comprised of [24]crown-8 rings-each of which incorporate two imine bonds-encircling a dumbbell component composed of a dibenzylammonium ion in which each of the two benzyl substituents carries two methoxyl groups attached to their 3- and 5-positions. A mechanism for the partial disassembly of the two dynamic [2]rotaxanes, involving the cleavage of the kinetically labile imine bonds by water molecules, is proposed.

Insight into the hard-soft acid-base properties of differently substituted phenylhydrazines in reactions with dimethyl carbonate.

Following the preliminary studies on the reactivity of the ambident nucleophile phenylhydrazine with dimethyl carbonate, investigations involving para-substituted phenylhydrazines were carried out in order to probe differences in the reactivity within this class of nucleophile. Phenylhydrazines substituted by electron withdrawing or donating substituents showed an increase in reactivity of the phenylhydrazine toward dimethyl carbonate. Under the basic conditions used, all phenylhydrazines displayed hard nucleophilicity, signifying that para-substitution on the phenyl ring has little effect on the hard-soft behavior of this class of nucleophile.

Reaction of the ambident electrophile dimethyl carbonate with the ambident nucleophile phenylhydrazine.

To explore the ambident electrophilic reactivity of dimethyl carbonate (DMC), reactions with the ambident nucleophile phenylhydrazine were investigated. When a Brönsted base was used, selective carboxymethylation occurred at N-1, after that several other compounds were produced selectively utilizing various conditions. Formation of these compounds was explained by using the Hard-Soft Acid-Base (HSAB) theory.

Template-directed synthesis of mechanically interlocked molecular bundles using dynamic covalent chemistry.

Mixing the dipyrido[24]crown-8 derivatives carrying one or two formyl group(s) on the 4 position(s) of their pyridine ring(s) with a 3-fold symmetrical trisammonium ion template in a 3:1 ratio in CD3NO2 results in the formation of thermodynamically stable [4]pseudorotaxanes which, upon addition of a 1,3,5-trisaminobenzene cap, form mechanically interlocked molecular bundles with one and two caps, respectively, by virtue of dynamic imine bond formation.

Template-directed synthesis of multiply mechanically interlocked molecules under thermodynamic control.

The template-directed construction of crown-ether-like macrocycles around secondary dialkylammonium ions (R2NH2+) has been utilized for the expedient (one-pot) and high-yielding synthesis of a diverse range of mechanically interlocked molecules. The clipping together of appropriately designed dialdehyde and diamine compounds around R2NH2+-containing dumbbell-shaped components proceeds through the formation, under thermodynamic control, of imine bonds. The reversible nature of this particular reaction confers the benefits of "error-checking" and "proof-reading", which one usually associates with supramolecular chemistry and strict self-assembly processes, upon these wholly molecular systems.

Template-directed dynamic synthesis of mechanically interlocked dendrimers.

The versatility and efficiency of dynamic covalent chemistry (DCC) has been exploited in the convergent synthesis of mechanically interlocked dendrimers that are based upon the mutual recognition expressed between secondary dialkylammonium ions and crown ether-like macrocycles. Reversible imine bond formation is employed to clip two acyclic fragments, one of them a diformylpyridine unit bearing a dendritic side chain, and the other a complementary dianiline in the shape of the di(o-aminophenyl)ether of tetraethylene glycol, around each arm of a tritopic trisammonium ion core, thereby affording a branched [4]rotaxane. This template-directed strategy has been demonstrated to work in very high yields (>90%) with successive generations (G0-G2) of a modified Fréchet-type dendritic wedge attached to the 4-position of the diformylpyridine unit.

Synthesis of a [2]catenane around a Ru(diimine)3(2+) scaffold by ring-closing metathesis of olefins.

[reaction: see text] The synthesis of a ruthenium[2]catenane is described. One ring includes two 1,10-phenanthroline moieties, the other a bipyridinic unit. The interlocking ring system was formed by using a double ring closing metathesis reaction.