453 research outputs found
Recommended Tests for the Self-Disproportionation of Enantiomers (SDE) to Ensure Accurate Reporting of the Stereochemical Outcome of Enantioselective Reactions
The purpose of this review is to highlight the necessity of conducting tests to gauge the magnitude of the self-disproportionation of enantiomers (SDE) phenomenon to ensure the veracity of reported enantiomeric excess (ee) values for scalemic samples obtained from enantioselective reactions, natural products isolation, etc. The SDE always occurs to some degree whenever any scalemic sample is subjected to physicochemical processes concomitant with the fractionation of the sample, thus leading to erroneous reporting of the true ee of the sample if due care is not taken to either preclude the effects of the SDE by measurement of the ee prior to the application of physicochemical processes, suppressing the SDE, or evaluating all obtained fractions of the sample. Or even avoiding fractionation altogether if possible. There is a clear necessity to conduct tests to assess the magnitude of the SDE for the processes applied to samples and the updated and improved recommendations described herein cover chromatography and processes involving gas-phase transformations such as evaporation or sublimation
A Call for a Change in Policy Regarding the Necessity for SDE Tests to Validate the Veracity of the Outcome of Enantioselective Syntheses, the Inherent Chiral State of Natural Products, and Other Cases Involving Enantioenriched Samples
We wish to draw attention to an important issue concerning scientific practice with regard to enhancing the quality of publications in Molecules (as well as for other journals) [...
Yak production in central Asian highlands: Proceedings of the third international congress on yak held in Lhasa, P.R. China, 4-9 September 2000
FIRST: A Million-Entry Dataset for Text-Driven Fashion Synthesis and Design
Text-driven fashion synthesis and design is an extremely valuable part of
artificial intelligence generative content(AIGC), which has the potential to
propel a tremendous revolution in the traditional fashion industry. To advance
the research on text-driven fashion synthesis and design, we introduce a new
dataset comprising a million high-resolution fashion images with rich
structured textual(FIRST) descriptions. In the FIRST, there is a wide range of
attire categories and each image-paired textual description is organized at
multiple hierarchical levels. Experiments on prevalent generative models
trained over FISRT show the necessity of FIRST. We invite the community to
further develop more intelligent fashion synthesis and design systems that make
fashion design more creative and imaginative based on our dataset. The dataset
will be released soon.Comment: 11 pages, 8 figure
Kitamura Electrophilic Fluorination Using HF as a Source of Fluorine
This review article focused on the innovative procedure for electrophilic fluorination using HF and in situ generation of the required electrophilic species derived from hypervalent iodine compounds. The areas of synthetic application of this approach include fluorination of 1,3-dicarbonyl compounds, aryl-alkyl ketones, styrene derivatives, α,β-unsaturated ketones and alcohols, homoallyl amine and homoallyl alcohol derivatives, 3-butenoic acids and alkynes.This research was funded by the National Natural Science Foundation of China (No. 21761132021), and IKERBASQUE, Basque Foundation for Science
Synthesis of Aminoalkyl Sclareolide Derivatives and Antifungal Activity Studies
Sclareolide was developed as an efficient C-nucleophilic reagent for an asymmetric Mannich addition reaction with a series of N-tert-butylsulfinyl aldimines. The Mannich reaction was carried out under mild conditions, affording the corresponding aminoalkyl sclareolide derivatives with up to 98% yield and 98:2:0:0 diastereoselectivity. Furthermore, the reaction could be performed on a gram scale without any reduction in yield and diastereoselectivity. Additionally, deprotection of the obtained Mannich addition products to give the target sclareolide derivatives bearing a free N-H group was demonstrated. In addition, target compounds 4–6 were subjected to an antifungal assay in vitro, which showed considerable antifungal activity against forest pathogenic fungi.Financial support from the National Natural Science Foundation of China (Nos. 21761132021 and 21606133) and IKERBASQUE, Basque Foundation for Science
New Approved Drugs Appearing in the Pharmaceutical Market in 2022 Featuring Fragments of Tailor-Made Amino Acids and Fluorine
The strategic fluorination of oxidatively vulnerable sites in bioactive compounds is a relatively recent, widely used approach allowing us to modulate the stability, bio-absorption, and overall efficiency of pharmaceutical drugs. On the other hand, natural and tailor-made amino acids are traditionally used as basic scaffolds for the development of bioactive molecules. The main goal of this review article is to emphasize these general trends featured in recently approved pharmaceutical drugs.This research was funded by the National Natural Science Foundation of China (No. 21761132021) and IKERBASQUE, Basque Foundation for Science
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