Oxidative esterification of biomass-derived 5-(hydroxymethyl) furfural (HMF) and furfural and their derivatives has been performed using a simple MnO2/NaCN system.
An efficient strategy
was developed for directing-group-free C–H
functionalization of biomass-derived C6 furanic building
block. Palladium-catalyzed C–H functionalization of the low-reactive
C3 position was successfully performed in 2,5-diformylfuran, an important
derivative of the biobased platform chemical 5-(hydroxymethyl)furfural.
The ligand-free catalytic arylation was carried out without using
protecting or directing groups, which is of key importance for the
studied area to achieve waste-minimized and step-economic biomass
processing. The experimental results combined with density functional
theory calculations revealed a reaction mechanism and indicated that
the presence of the aldehyde group is essential for catalytic reaction.
Enolization of the aldehyde group and Pd binding play an important
role in governing the overall C–H functionalization pathway.
One of the obtained arylated furanic compounds was tested as a model
substrate for reduction and oxidation of carbonyl groups to highlight
its versatile synthetic potential.
An atom-economic ring construction approach to the synthesis of α-(hetero)arylfurans based on renewable furanic platform chemicals has been developed. Corresponding compounds have been prepared in good to excellent yields via [2 + 2 + 2] and [4 + 2] cycloaddition reactions using metal-catalyzed or photoredox protocols. Easily available HMF-based 2-hydroxymethyl-5-ethynylfuran and 2hydroxymethyl-5-cyanofuran were used as starting materials.A synthetic route with an improved carbon economy factor has been implemented to achieve sustainability aim. The possible application of arylfurans as molecular conductors has been investigated by DFT calculations, which revealed excellent charge transfer properties. As a future perspective, integration of biomass processing strategy into manufacturing of molecular electronics was pointed out to achieve the aim of sustainability.
Visual search (VS) for multiple targets is especially error prone. One of these errors is called subsequent search misses (SSM) and represents a decrease in accuracy at detecting a second target after a first target has been found. One of the possible explanations of SSM errors is working memory (WM) resource depletion. Three experiments investigated the role of WM in SSM errors using a dual task paradigm. The first experiment investigated the role of object WM using a classical color change detection task. In the second and the third experiments, a modified change detection task was applied, using shape as the relevant feature. The results of our study revealed no effect of additional WM task on second target detection in dual-target VS. To this end, SSM errors are not related to WM resource depletion. On the contrary, WM task performance was violated by dual-target VS as compared to single-target VS, when the targets in VS task were defined by the same feature used in the WM task.
Biomass-derived C6-furanic compounds have become the cornerstone of sustainable technologies. The key feature of this field of chemistry is the involvement of the natural process only in the first step, i.e., the production of biomass by photosynthesis. Biomass-to-HMF (5-hydroxymethylfurfural) conversion and further transformations are carried out externally with the involvement of processes with poor environmental factors (E-factors) and the generation of chemical wastes. Due to widespread interest, the chemical conversion of biomass to furanic platform chemicals and related transformations are thoroughly studied and well-reviewed in the current literature. In contrast, a novel opportunity is based on an alternative approach to consider the synthesis of C6-furanics inside living cells using natural metabolism, as well as further transformations to a variety of functionalized products. In the present article, we review naturally occurring substances containing C6-furanic cores and focus on the diversity of C6-furanic derivatives, occurrence, properties and synthesis. From the practical point of view, organic synthesis involving natural metabolism is advantageous in terms of sustainability (sunlight-driven as the only energy source) and green nature (no eco-persisted chemical wastes).
Visual search for multiple targets is especially error prone. One of these errors is called subsequent search misses (SSM) and represents a decrease in accuracy at detecting a second target after a first target has been found. One of the possible explanations of SSM errors is working memory resource depletion. Four experiments investigated the role of different kinds of working memory in SSM errors. The first experiment investigated the role of object working memory using a classical color change detection task. In the second and the third experiments, a modified change detection task was applied, using shape as the relevant feature. In the fourth experiment, a spatial working memory task was used to reveal the role of spatial working memory in SSM. The second and the third experiments revealed interference between working memory and visual search tasks, whereas in the first and the fourth experiments interference was not found. The results are discussed in terms of specific working memory deficit in SSM errors. JEL Classification: Z.
Subsequent search misses can occur during visual search for several targets. SSM is a decrease in accuracy at finding a second target after successful detection of a first one. Two experiments investigated the effect of object working memory load, target stimuli similarity and the similarity of stimuli in visual search task and working memory tasks on the SSM. It was found that targets perceptual similarity is significant, as well as memory load in case of working memory task and visual search task stimuli similarity. In addition, we found a significant interaction between working memory load and number of shared features between two target stimuli, which may indicate a common mechanism underlying the role of working memory load and perceptual similarity factors.
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