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5-(Chloromethyl)furfural (CMF) is a cellulose derivative of increasing appeal as a renewable platform molecule. Although its role as an electrophile has been broadly studied, little is known about ...

Biobased 5-(chloromethyl)furoate and 5-methylfuroate esters can be deprotonated to function as furylogous lithium enolates, and the former can also undergo zinc insertion to access Reformatsky-type chemistry. Carbon nucleophilicity represents hitherto little-explored reactivity in these key carbohydrate-derived platform molecules, expanding their synthetic utility and potentially opening up new sustainable product markets (e. g., in epoxy resins or biobased dyes).

5-(Chloromethyl)furfural (CMF) is a carbohydrate-derived platform molecule that is gaining traction as a more practical alternative to 5-(hydroxymethyl)furfural (HMF). This perspective introduces the chemocatalytic approach to biorefining as the driving force behind the development of multifunctional chemical platforms. The main advantage of CMF over HMF is that it can be produced in high yield under mild conditions directly from raw biomass. Its stability and hydrophobicity markedly facilitate isolation. CMF is also a precursor to levulinic acid (LA), another versatile biobased intermediate. The logistics of CMF production are discussed, including reactor materials, HCl handling and management, byproducts, and the fate of collateral biomass components (hemicellulose, lipids, proteins, lignin). Examples of commercial markets that can be unlocked by synthetic manipulation of CMF are broken out into two derivative manifolds, furanic and levulinic, which are distributed over three product family trees: renew...

Furandioate-adipate copolyesters are an emerging class of bio-based biodegradable polymers with great potential to replace fossil-derived terephthalic acid-based copolyesters such as poly(butylene adipate-co-terephthalate) (PBAT). Furandioate-adipate polyesters have almost exclusively been prepared with conventional primary (1°) alcohol diols, while secondary (2°) alcohol diol monomers have largely been overlooked until now, despite preliminary observations that using methyl-branched diols increases the Tg of the resultant polyesters. Little is known of what impact the use of 2° alcohol diols has on other properties such as material strength, hydrophobicity, and rate of enzymatic hydrolysis—all key parameters for performance and end-of-life. To ascertain the effects of using 2° diols on the properties of furandioate-adipate copolyesters, a series of polymers from diethyl adipate (DEA) and 2,5-furandicarboxylic acid diethyl ester (FDEE) using different 1° and 2° alcohol diols was prepared. Longer transesterification times and greater excesses of diol (diol/diester molar ratio of 2:1) were found to be necessary to achieve Mws > 20 kDa using 2° alcohol diols. All copolyesters from 2° diols were entirely amorphous and exhibited higher Tgs than their linear equivalents from 1° diols. Compared to linear poly(1,4-butyleneadipate-co-1,4-butylenefurandioate), methyl-branched, poly(2,5-hexamethyleneadipate-co-2,5-hexamethylenefurandioate) (0:7:0.3 furandioate/adipate ratio) displayed both higher modulus (67.8 vs 19.1 MPa) and higher extension at break (89.7 vs 44.5 mm). All other methyl-branched copolyesters displayed lower modulus but retained higher extension at break compared with their linear analogues. Enzymatic hydrolysis studies using Humicola insolens cutinase revealed that copolyesters from 2° alcohol diols have significantly decreased rates of biodegradation than their linear equivalents synthesized using 1° alcohol diols, allowing for fine-tuning of polymer stability. Hydrophobicity, as revealed by water contact angles, was also found to generally increase through the introduction of methyl branching, demonstrating potential for these materials in coatings applications., Methyl branching in secondary diols has been found to increase the Tg, hydrophobicity, and resistance to biodegradation relative to linear diols for a family of bio-based copolyesters, providing a valuable tool to fine-tune material performance.

The biomass-derived platform molecule levulinic acid is converted into the angelica lactone dimer (ALD) in high overall yield using simple inorganic catalysts. Hydrodecarboxylation of ALD using a Pd/γ-Al2O3 catalyst under moderate hydrogen gas pressure at high temperatures generates branched C8–C9 hydrocarbons in nearly quantitative yield by consuming as little as a single equivalent of external hydrogen. These molecules are high-octane “drop-in” equivalents of isoalkanes used in commercial gasoline. Catalytic hydrodecarboxylation is presented as a highly effective means to reduce hydrogen demand in biomass-to-biofuel conversion technologies.

The dye and pigment manufacturing industry is one of the most polluting in the world. Each year, over one million tons of petrochemical colorants are produced globally, the synthesis of which generates a large amount of waste. Naturally occurring, plant-based dyes, on the other hand, are resource intensive to produce (land, water, energy), and are generally less effective as colorants. Between these two extremes would be synthetic dyes that are fully sourced from biomass-derived intermediates. The present work describes the synthesis of such compounds, containing strong chromophores that lead to bright colors in the yellow to red region of the visible spectrum. The study was originally motivated by an early report of an unidentified halomethylfurfural derivative which resulted from hydrolysis in the presence of barium carbonate, now characterized as a butenolide of 5-(hydroxymethyl)furfural (HMF). The method has been generalized for the synthesis of dyes from other biobased platform molecules, and a mechanism is proposed.

© 2015 Elsevier Ltd. 5-(Chloromethyl)furfural (CMF) is rapidly being established as a renewable platform chemical of great promise. The effects of mass transfer, reaction temperature, Hansen solvent parameters, solvent fraction, and initial glucose concentrations on yields of CMF, 5-(hydroxymethyl)furfural (HMF), 2-(hydroxyacetyl)furan (HAF), levulinic acid (LA), and humic matter were investigated in a two-phase system of 6M HCl and an organic solvent. The ability of the solvent to extract HMF from the aqueous phase is found to be critical to achieving high CMF yields. Effective solvents must possess at least a small degree of Hansen hydrogen bonding capacity, and a high polarity is beneficial. Yields of CMF and HAF decrease with increasing glucose concentration but the yield of HMF is largely unaffected. The maximum productivity of CMF is achieved at a glucose loading of ca. 1.5M across all solvent fractions tested.

5-(Chloromethyl)furfural (CMF) is a disruptive innovation in the biorefinery. Chemically, it is at least as versatile as the well-known HMF but, unlike HMF, it is accessible in high yield directly from cellulosic biomass due to its lipophilicity and stability under acidic conditions, which facilitate isolation. It has a rich derivative chemistry that includes biofuels, renewable polymers, specialty chemicals, and value-added agrochemical and pharmaceutical products.

An efficient synthetic approach to furan fatty acids starting from the biomass-derived platform chemical 5-(chloromethyl)furfural (CMF) is described. The route involves seven steps and has a 60% overall yield. Furan fatty acids are dietary antioxidants that occur naturally in fish and are proposed to have anti-atherosclerotic properties. The free radical scavenging abilities of synthetic furan fatty acids were evaluated against butylated hydroxytoluene (BHT) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay.

A practical, scalable, metal-free synthesis of succinic acid from the biomass-derived platform chemical levulinic acid is described. Treatment of levulinic acid with the inexpensive, simple oxidant hydrogen peroxide under the catalytic action of trifluoroacetic acid gives succinic acid in high yield and enables facile product isolation by simple distillation of the volatile catalyst and byproducts.

A family of monomers, including 2,5-hexandiol, 2,7-octandiol, 2,5-furandicarboxylic acid (FDCA), terephthalic acid (TA), and branched-chain adipic and pimelic acid derivatives, all find a common derivation in the biomass-derived platform molecule 5-(chloromethyl)furfural (CMF). The diol monomers, previously little known to polymer chemistry, have been combined with FDCA and TA derivatives to produce a range of novel polyesters. It is shown that the use of secondary diols leads to polymers with higher glass transition temperatures (Tg) than those prepared from their primary diol equivalents. Two methods of polymerisation were investigated, the first employing activation of the aromatic diacids via the corresponding diacid chlorides and the second using a transesterification procedure. Longer chain diols were found to be more reactive than the shorter chain alternatives, generally giving rise to higher molecular weight polymers, an effect shown to be most pronounced when using the transesterification route. Finally, novel diesters with high degrees of branching in their hydrocarbon chains are introduced as potential monomers for possible low surface energy materials applications.

5-(Halomethyl)furfurals (XMFs) are biomass-derived platform chemicals that are gaining traction as practical alternatives to 5-(hydroxymethyl)furfural (HMF). This chapter provides an overview of the historical role of XMFs in the chemical investigation of carbohydrates and describes multiple approaches to their preparation, including recent breakthroughs by which XMFs, and in particular 5-(chloromethyl)furfural (CMF), are obtained in high yield directly from raw biomass. Halomethylfurfurals have two basic derivative manifolds: furanic and levulinic, and this chapter will highlight commercial markets that can be unlocked by synthetic manipulation of CMF and its immediate derivatives.

Prothrin, a synthetic pyrethroid insecticide, was synthesized from the biomass-derived platform chemical 5-(chloromethyl)furfural in six steps and overall 65% yield. Two structural analogues of prothrin were also prepared following the same synthetic approach. Preliminary testing of these furan-based pyrethroids against the yellow fever mosquito Aedes aegypti indicates promising insecticidal activities.

3-Hydroxypropanoic acid (HPA), a precursor to acrylic acid, can be produced in high yield by oxidation of the biomass-derived platform chemical levulinic acid. While treatment of levulinic acid with H2 O2 under acidic conditions gives predominantly succinic acid, a remarkable reversal of selectivity is observed under basic conditions, leading either directly to HPA or, under modified conditions, initially to 3-(hydroperoxy)propanoic acid, which can be quantitatively hydrogenated to HPA.

Acid chloride derivatives of 5-(chloromethyl)furan-2-carboxylic acid and furan-2,5-dicarboxylic acid (FDCA) can be produced in high yield by treatment of the precursor aldehydes 5-(chloromethyl) furfural (CMF) and 2,5-diformylfuran (DFF) with tert-butyl hypochlorite, which is inexpensively prepared from commercial bleach and tert-butanol. 5-(Chloromethyl)furan-2-carbonyl chloride (CMFCC) and furan-2,5-dicarbonyl chloride (FDCC) are highly useful intermediates for the production of furoate ester biofuels and polymers of FDCA.

Recently, a new processing technique was developed that converts the carbohydrates found in plant biomass into ethyl levulinate, which has properties making it a possible diesel fuel oxygenate additive. Additionally, the new processing technique applied to oil-containing seeds can create a biodiesel fuel at high yields, while possibly enhancing the cold flow properties that commonly plague biodiesel fuels. The first part of this two-part study focused on ethyl levulinate as a possible diesel fuel oxygenate additive, by investigating the volatility of petroleum diesel/ethyl levulinate mixtures. Volatility was measured with the advanced distillation curve (ADC) method for mixtures containing 1, 2.5, 5, 10, and 20% ethyl levulinate (v/v) and compared with unblended petroleum diesel fuel. In addition, the concentration of ethyl levulinate was tracked during the distillation for each mixture by use of the composition explicit data channel. The second part of this study investigated fatty acid−levulinate ester ...

2,5-Dimethylfuran (DMF) is one of the most actively pursued biomass-derived chemicals due to the fact that it can serve both as a biofuel and an intermediate for drop-in terephthalate polymers. DMF can be accessed via catalytic hydrogenation of 5-(hydroxymethyl)furfural (HMF), but the difficult accessibility of HMF from cellulosic biomass is a major impediment to the commercial development of such a process. Alternatively, 5-(chloromethyl)furfural (CMF) is freely accessible in high yield directly from raw biomass and is shown here to be efficiently reduced to DMF under mild conditions via simple derivatives (aldimine, acetal).

5-(Hydroxymethyl)furfural, levulinic acid, ethyl levulinate and butyl levulinate are produced by the solvolysis of 5-(chloromethyl)furfural (CMF). Since CMF can be derived in high yield from sugars, cellulose, or lignocellulosic feedstocks, the process described here presents an efficient entry into the value-added manifold of biomass-derived products of relevance to the organic materials and fuel industries.

Aromatic molecules have a strong affinity for silver(I) and dissolve to a limited extent in Ag 0.51K 0.42Na 0.07NO 3, a low-melting eutectic mixture of silver, potassium, and sodium nitrates. Aromatic nitration in this inorganic ionic liquid leads to products which arise from nonelectrophilic substitution pathways.

Heteroatom-substituted acepentalene derivatives which are isoelectronic with the known acepentalenediide dianion are nonplanar, fused aromatic tricycles which are hemifullerenes of the corresponding C20 heteroanalogue. Depending on the number and position of heteroatoms, they may be anionic, neutral, or cationic. A nucleus-independent chemical shift study indicates that substitution of the central carbon of the acepentalenediide system with N or O results in a substantial increase in aromaticity. Peripheral aza substitution on the other hand tends to increase curvature and decrease aromaticity. Alkylation or protonation at the central position of asymmetrically substituted heteroacepentalenides leads to chiral, bowl-shaped, 10 pi aromatic species.

The lignin by-product of the conversion of lignocellulosic biomass to 5-(chloromethyl)furfural (CMF) has been characterised by thermogravimetric analysis, N2 physisorption porosimetry, attenuated internal reflectance IR spectroscopy, elemental analysis and solid-state NMR spectroscopy. The lignin (LCMF) has a moderate level of mesoporosity before thermal treatment and a surface area of 63 m(2) g(-1) , which increases dramatically on pyrolysis at temperatures above 400 °C. An assessment of the functionality and textural properties of the material was achieved by analysing LCMF treated thermally over a range of pyrolysis temperatures. Samples were sulfonated to test their potential as heterogeneous acid catalysts in the esterification of levulinic acid. It was shown that unpyrolysed catalysts gave the highest ester yields of up to 93 %. To the best of our knowledge, this is the first example of mesoporous lignin with an appreciable surface area that is produced directly from a bio-refinery process and with further textural modification of the material demonstrated.

The growth and structures of three new cocrystalsC9Cl6Br3N·C60, C9Cl6Br3N·C70, and C9Cl6H3N·3C70·3C6H5Clinvolving fullerenes and halogenated azatriquinacenes are reported. In each case, the fullerene is completely ordered and avoids the orientational disorder found in many crystalline fullerenes and fullerene cocrystals. In each structure, the upper Cl6 surface of the halogenated azatriquinacene molecule cups a fullerene. In C9Cl6Br3N·C60 and C9Cl6Br3N·C70, the molecules are arranged alternately in columns with the lower Br3 face of the azatriquinacene also interacting with a neighboring fullerene. In C9H3Cl6N·3C70·3C6H5Cl, one of the fullerenes is cupped by the upper surface of the azatriquinacene, while four chlorobenzene molecules also form a belt around it.

Molecules which possess the hydrogen bonding codes of both guanine and cytosine (“G−C DNA base hybrids”) are known to organize in a hexagonal array both in solution and the solid state. Including an easily derivatizable functional group in the molecule allows the co-organization of virtually any species in the hexagonal periphery. Simple 5- and 6-step procedures are described for the synthesis of DNA base hybrids with tail groups which are terminated by electrophilic (primary bromide) and nucleophilic (primary alcohol) functions, respectively.

In a recent paper entitled "Efficient One-Pot Synthesis of 5-Chloromethyl-furfural (CMF) from Carbohydrates in Mild Biphasic Systems," published in Molecules [1], Gao and coworkers describe the use of a biphasic aq. HCl-H3PO4/CHCl3 reagent for the preparation of CMF from various feedstocks. The maximum yield (46.8%) was obtained from fructose by reaction at 45 °C for 20 h. While sucrose gave a similar yield, the same reaction with glucose and cellulose gave 7.3% and 7.8% yields, respectively. Remarkably, the same process applied to Kraft pulp and powdered wood samples gave between 16.0% and 31.4% CMF, based on sugar content. Looking to the Experimental section for insight into this unusual outcome, the statement, "the procedure of treating lignocellulose sample (Table 6) was almost the same as the carbohydrate, except adding the selected simple 1.0 mg each trial " [sic] appears, which is difficult to interpret.

The synthesis and chemistry of 5-(hydroxymethyl)furfural (HMF), 5-(chloromethyl)furfural (CMF), and levulinic acid (LA), three carbohydrate-derived platform molecules produced by the chemical-catalytic processing of lignocellulosic biomass, is reviewed. Starting from the historical derivation of these molecules and progressing through modern approaches to their production from biomass feedstocks, this review will then survey their principal derivative chemistries, with particular attention to aspects of commercial relevance, and discuss the relative merits of each molecule in the future of biorefining.

Cheap fossil oil resources are becoming depleted and crude oil prices are rising. In this context, alternatives to fossil fuel-derived carbon are examined in an effort to improve the security of carbon resources through the development of novel technologies for the production of chemicals, fuels, and materials from renewable feedstocks such as biomass. The general concept unifying the conversion processes for raw biomass is that of the biorefinery, which integrates biofuels with a selection of pivot points towards value-added chemical end products via so-called “platform chemicals”. While the concept of biorefining is not new, now more than ever there is the motivation to investigate its true potential for the production of carbon-based products. A variety of renewable chemicals have been proposed by many research groups, many of them being categorized as drop-ins, while others are novel chemicals with the potential to displace petrochemicals across several markets. To be competitive with petrochemicals, carbohydrate-derived products should have advantageous chemical properties that can be profitably exploited, and/or their production should offer cost-effective benefits. The production of drop-ins will likely proceed in short term since the markets are familiar, while the commercial introduction of novel chemicals takes longer and demands more technological and marketing effort.

Azatriquinenamine (5) is the entry point into the azatriquinane heterocycles. Its convex morphology and enamine function involving a bridgehead double bond lead to unusual reactivity. Bromination of 5 gives either a mono- (7) or tetrabromo (8) derivative depending on conditions, the latter of which is highly congested sterically and undergoes unexpected ring opening, rearrangement, and hydrolysis reactions. Careful elimination of HBr from 8 gives a potential precursor (14) to azatriquinene 6, and a dehydrobromination, bromination protocol leads to a potential precursor (18) to azatriquinacene 2.

The synthesis of 1,4,7-trimethyloxatriquinane (1), a 3-fold tertiary alkyl oxonium salt, is described. Compound 1 is inert to solvolysis with alcohols, even at elevated temperatures, but undergoes facile substitution with the strongly nucleophilic azide anion. Since an S(N)1 pathway is excluded, the only reasonable mechanistic interpretation for the reaction between 1 and N(3)(-) is S(N)2, despite the fact that substitution is occurring at a tertiary carbon center. This finding is supported by computational modeling and a study of the reaction kinetics, and is also consistent with observed solvent and salt effects.

The guanine−cytosine base hybrid 1 is synthesized in five steps from the malononitrile dimer. One face of the molecule possesses the cytosine AAD hydrogen bonding code and the other the guanine DDA...

Azatriquinane, a tricyclic amine with rigid, hemispherical topology, is synthesized in six steps from pyrrole. This first example of a [2.2.2]cyclazine can be oxidatively dimerized to a novel, highly strained heptacycle or oxidized with chlorine to give an azatriquinacene, a theoretical precursor to diazadodecahedrane via Woodward dimerization.

N-substituted pyrido[4,3-d]pyrimidines are heterocycles which exhibit the asymmetric hydrogen bonding codes of both guanine and cytosine at 60° angles to each other, such that the molecules self-organize unambiguously into a cyclic hexamer, assembled via 18 intermolecular hydrogen bonds. The synthesis is straightforward and can be concluded in six steps from the commercially available malononitrile dimer. X-ray crystallographic analysis of the supermacrocyclic structure shows an undulating disk with a ca. 10.5 A cavity, the centers of which do not overlap sufficiently to describe a channel in the solid state. However, AFM, SEM, and TEM imaging in solution reveals the formation of 1D nanostructures in agreement with their self-assembly into rosette supermacrocycles, which then stack linearly to form rosette nanotubes.

Incorporation of triquinane ring systems into a macrobicyclic framework enables the stabilization of unusual bonding arrangements, including 3-center-2-electron cation, 3-center-3-electron radical, and 3-center-4-electron anion systems, linear divalent fluorine, triplet carbenes, record short C-C bonds, a powerful proton sponge effect, and oxadionium (R4O(2+)) ions. The means to stabilize and conceivably isolate such species derives from the rigid, convex nature of the triquinane ring system, as well as the substitution of positions adjacent to the bridgeheads atoms which would otherwise be vulnerable to elimination. The potential realization of hitherto undescribed bonding outcomes makes these macrocycles provocative synthetic targets.

Azatriquinane, an amine with a rigid, hemispherical topology, is synthesized in six steps from pyrrole. It is shown to be more basic than quinuclidine, and can be dimerized by N-oxidation and treatment with base to give novel, highly strained heptacycle. Oxidation with chlorine gives an azatriquinacene, a theoretical precursor to diazadodecahedrane.

Irradiation of the trichloroacetates 2, 4 and 5, derived from the corresponding tryptophols, in methanolic acetonitrile results In photocyclisation to the indole 4-position, and the formation of the pyrrolobenzoxocines 9–11. Attempted photocyclisation of the ‘reversed’α-chloro esters 15a, 15b and 18 was thwarted by readily occurring elimination of HCl, although the dimethyl compound 15c did cyclise to give the cycloheptaindole 20 upon irradiation in acetonitrile.

From biomass to mass transportation: Waste biomass (newspaper, corn stover, straw, and wood) is converted into biofuel precursors and value-added products in excellent yield using a simple, inexpensive process involving concurrent hydrolysis, dehydration, and substitution reactions in a biphasic reactor. The hemicellulose fraction of these substrates is simultaneously converted into furfural, and together these constitute an efficient means for the total exploitation of the carbohydrate content of biomass.

The first example of a vinylogous Witkop cyclisation produces a novel azonino[c,d]indole, a carbocyclic analogue of the tumour-promoting indolactam family of natural products. A similar reaction previously reported to give azecino[c,d]indoles leads only to azocino[c,d]indoles, even when the radical centre is stabilised by the presence of halogens.

[reaction: see text] Crystal structures of the one-to-one co-crystals of C(60).perchloroazatriquinacene and C(70).perchloroazatriquinacene show that the rigid, chalice-like azatriquinacene packs between completely ordered fullerene molecules with multiple, close Cl...fullerene contacts.

The activation barriers and energy profiles along the inclusion coordinate for the penetration of H+, He, Li+, Be+, Be2+, and Mg2+ into dodecahedrane 1 vary considerably with the nature of the projectile. Using Hartree-Fock and MP2 derived structures and energies, the overall process of creating endohedral X n+@1 complexes is examined in detail.

Cellulose-derived 5-(chloromethyl)furfural is converted into δ-aminolevulinic acid in three chemical steps involving conversion to 5-(azidomethyl)furfural, photooxidation, and catalytic hydrogenation in 68% overall yield. δ-Aminolevulinic acid is a natural product with important agrochemical and pharmaceutical applications.

Oxatriquinane, a fused, tricyclic alkyl oxonium ion of unprecented stability, was synthesized in five steps from 1,4,7-cyclononatriene. It survives reflux in H2O, chromatography, and attack by alcohols, alkyl thiols, halide ions, and hindered amine bases. The X-ray crystal structure shows longer C-O bond distances and more acute C-O-C bond angles than any reported alkyloxonium salt. The corresponding oxatriquinene and oxatriquinacene were also synthesized and represent the first examples of stable allyl oxonium species.

[reaction: see text] Tryptophan-derived azoninoindole imines select partners of the same chirality for dimerization to helical macrocycles.