Regioselective synthesis, isomerisation, in vitro oestrogenic activity, and copolymerisation of bisguaiacol F (BGF) isomers

Abstract

Biobased ortho-methoxy groups ameliorate classic bisphenol chemistry in terms of synthesis, safety and processing; bisguaiacol F is used as a test case.

Experimental resin-modified calcium-silicate cement containing N-(2-hydroxyethyl) acrylamide monomer for pulp tissue engineering

“…Regarding HEMA, this small hydrophilic monomer promotes water uptake, as well as it was shown to be cytotoxic towards human cells [27,28]. On the other hand, new alternative monomers from natural origin have recently been developed with potential to be used in dental materials [21,29]. The above sketched rationale is the main reason why we decided in this research to substitute Bis-GMA and HEMA, respectively, with UDMA (25wt%), already used in resin-based dental materials, and FAM-401 (5wt%).…”

A guide towards safe, functional and renewable BPA alternatives by rational molecular design: structure–property and structure–toxicity relationships

“…When p-vanillyl alcohol was coupled with guaiacol in the presence of a heterogeneous ion-exchanging catalyst (i.e., Amberlyst-15), only three different regioisomers of BGF were obtained: the p,p′-(2), m,p′-( 22) and o,p′-isomer (21), with an isomer distribution of 82%, 15% and 3%, respectively. To investigate the physical appearance and properties of the m,p′and o,p′-isomer, Koelewijn et al (2019) 59 selectively synthesized these isomers using vanillyl alcohol isomers (e.g., mand o-vanillyl alcohol), thereby shifting the isomer distribution. Interestingly, the m,p′-isomer showed a significantly higher melting point (119-120 °C) than the p,p′-(99-100 °C) and o,p′-isomer (103-105 °C).…”

Estrogenic activity of lignin-derivable alternatives to bisphenol A assessed via molecular docking simulations

“…5,[7][8][9] BPA also is a suspected endocrine disruptor compound because it can mimic the natural estrogen hormone 17b-estradiol (E2) by binding to estrogen receptor alpha (ERa). 5,6,[9][10][11][12][13] The disruption of the endocrine system can lead to severe human health impacts, including diabetes, 14 obesity, 15 cardiovascular diseases, 16 reproductive disorders, 17 and cancer. 2,18 Therefore, several countries have restricted or eliminated BPA use in food contact applications.…”

“…Moreover, the methoxy groups on lignin-aromatics are likely helpful to mitigate the toxicity concerns of conventional aromatics. 5,6 Recently, lignin-derivable bisguaiacols (renewable bisphenols) have been reported as potentially safer alternatives to commercial bisphenols, 2,10,11,[47][48][49] with the suggestion being that their methoxy substituents ortho to the hydroxyl group sterically reduce binding to estrogen receptors mediated by those phenolic hydroxyls. 5,6,10 Additionally, these bisguaiacol-based polymeric systems retained desirable thermomechanical properties.…”

“…5,6 Recently, lignin-derivable bisguaiacols (renewable bisphenols) have been reported as potentially safer alternatives to commercial bisphenols, 2,10,11,[47][48][49] with the suggestion being that their methoxy substituents ortho to the hydroxyl group sterically reduce binding to estrogen receptors mediated by those phenolic hydroxyls. 5,6,10 Additionally, these bisguaiacol-based polymeric systems retained desirable thermomechanical properties. 47 For example, 4,4-methylenedianiline (MDA)-cured diglycidyl ethers of the bisguaiacols exhibited glass transition temperatures (T g s) between $111 C and $151 C, 5 wt% degradation temperatures (T d5% s) between $344 C and $368 C, and glassy storage moduli (E 0 ) between $2.0 GPa and $3.2 GPa at 30 C. 47 These thermomechanical properties were comparable to those of the MDAcured diglycidyl ether of BPF (T g $ 138 C; T d5% $ 375 C; E 0 $ 2.4 GPa at 30 C) likely because of the structural similarities of the bisguaiacols to BPF.…”