Impact of consumer behavior on furan and furan-derivative exposure during coffee consumption : a comparison between brewing methods and drinking preferences

This study examined the influence of consumer behavior on furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran and 2,3-dimethylfuran exposure in coffee. Coffees brewed using a filter, fully automatic, capsule machine or reconstituted instant coffee were found to have a significant different cup concentrations of furan derivatives. Coffee brewed with the fully automatic machine contained the highest furan and furan derivative concentrations (99.05 µg/L furan, 263.91 µg/L 2-methylfuran, 13.15 µg/L 3-methylfuran and 8.44 µg/L 2,5-dimethylfuran) whereas soluble coffee did not contain detectable levels, thereby contributing least to a consumer’s dietary exposure. Furan and furan derivative concentrations were found to decrease significantly upon cooling, reducing consumer exposure by 8.0-17.2% on average once the coffee reached drinking temperature 55-60°C, in ceramic cups. Serving coffee in a ceramic or disposable cup were found to influence the cooling dynamics of the coffee but did not statistically influence the consumers exposure at a given temperature

Expanding the Repertoire of Natural Product-Inspired Ring Pairs for Molecular Recognition of DNA

A furan amino acid, inspired by the recently discovered proximicin natural products, was incorporated into the scaffold of a DNA-binding hairpin polyamide. While unpaired oligomers of 2,4-disubstituted furan amino acids show poor DNA-binding activity, furan (Fn) carboxamides paired with N-methylpyrrole (Py) and N-methylimidazole (Im) rings demonstrate excellent stabilization of duplex DNA as well as discrimination of noncognate sequences, consistent with function as a Py mimic according to the Py/Im polyamide pairing rules

Furan-PNA : a mildly inducible irreversible interstrand crosslinking system targeting single and double stranded DNA

We here report on the design and synthesis of tailor-made furan-modified peptide nucleic acid (PNA) probes for covalent targeting of single stranded DNA through a crosslinking strategy. After introducing furan-containing building blocks into a PNA sequence, hybridization and furan-oxidation based crosslinking to DNA is investigated. The structure of the crosslinked products is characterized and preliminary investigations concerning the application of these systems to double stranded DNA are shown

Halogenation effects in Intramolecular Furan Diels-Alder reactions:broad scope synthetic and computational studies

For the first time a comprehensive synthetic and computational study of the effect of halogen substitution on both furan and dienophile for the intramolecular Furan Diels-Alder (IMDAF) reaction has been undertaken. Contrary to our initial expectations, halogen substitution on the dienophile was found to have a significant effect, making the reactions slower and less thermodynamically favourable. However, careful choice of the site of furan halogenation could be used to overcome dienophile halogen substitution, leading to highly functionalised cycloadducts. These reactions are thought to be controlled by the interplay of three factors: positive charge stabilisation in the transition state and product, steric effects and a dipolar interaction term identified by high level calculations. Frontier orbital effects do not appear to make a major contribution in determining the viability of these reactions, which is consistent with our analysis of calculated transition state structural data

The adsorption structure of furan on Pd(1 1 1)

The structure of molecular furan, C4H4O, on Pd(1 1 1) has been investigated by O K-edge near-edge X-ray absorption fine structure (NEXAFS) and C 1s scanned-energy mode photoelectron diffraction (PhD). NEXAFS shows the molecule to be adsorbed with the molecular plane close to parallel to the surface, a conclusion confirmed by the PhD analysis. Chemical-state specific C 1s PhD data were obtained for the two inequivalent C atoms in the furan, the α-C atoms adjacent to the O atom, and the β-C atoms bonded only to C atoms, but only the PhD modulations for the α-C emitters were of sufficiently large amplitude for detailed evaluation using multiple scattering calculations. This analysis shows the α-C atoms to be located approximately 0.6 Å off-atop surface Pd atoms with an associated C–Pd bondlength of 2.13 ± 0.03 Å. Two alternative local geometries consistent with the data place the O atom in off-atop or near-hollow locations, and for each of these local structures there are two equally-possible registries relative to the fcc and hcp hollow sites. The results are in good agreement with earlier density functional theory calculations which indicate that the fcc and hcp registries are equally probable, but the PhD results fail to distinguish the two distinct local bonding geometries

Electrochromic properties of a poly(dithienylfuran) derivative featuring a redox-active dithiin unit

A teraryl monomer containing a 1,4-dithiin-furan central unit has been synthesised and characterised by single crystal X-ray crystallography. The di(thienyl)furan monomer 11 was successfully polymerised electrochemically and shown to possess a lower electrochemical band gap than its terthiophene analogue (1.97 eV cf. 2.11 eV). The electrochromic properties of this polymer proved to be superior to PEDOT, with fast switching and reversible colour transformation at high colour contrast (CE = 212 cm(2) C-1 cf. 183 cm(2) C-1 for PEDOT at 95% optical switch)

Trialkylphosphine-mediated synthesis of 2-Acyl furans from ynenones

A novel reaction for the synthesis of 2-acyl furans is reported. The reaction is believed to proceed by sequential addition of a trialkylphosphine to an ynenone, 5-exo-dig cyclization to form the furan, and oxidation of the resulting phosphonium ylide with molecular oxygen. Many common functional groups are tolerated during the reaction, and the products are obtained in good to excellent yield under the mild conditions. This methodology offers efficient access to biologically important compounds, including fused polycyclic compounds and furaldehydes, from simple starting materials

Thioether-catalysed tandem synthesis of furans and cyclic ethers or lactones

Acyclic conjugated ynenediones tethered to an alcohol or carboxylic acid are converted into furanyl-substituted cyclic ethers or lactones in a single step by treatment with the tetrahydrothiophene. Modest levels of diastereocontrol can be achieved in some cases where the presence of a substituent on the tether results in the creation of a second stereogenic centre upon formation of the cyclic ether or lactone

Unusual structure-energy correlations in intramolecular Diels–Alder reaction transition states

Detailed analysis of calculated data from an experimental/computational study of intramolecular furan Diels–Alder reactions has led to the unusual discovery that the mean contraction of the newly forming C-C σ-bonds from the transition state to the product shows a linear correlation with both reaction Gibbs free energies and reverse energy barriers. There is evidence for a similar correlation in other intramolecular Diels–Alder reactions involving non-aromatic dienes. No such correlation is found for intermolecular Diels–Alder reactions