Ruthenium- and Cobalt-Catalyzed Chelation-Assisted C-H Functionalizations

Ruthenium- and cobalt-catalyzed C-H activations have been discribed in this thesis, which provided expedient routes to the synthesis of synthetically useful compounds. Moreover, detailed mechanistic studies were also investigated for the ruthenium- and cobalt-catalyzed C-H annulation, hydroarylation, arylation, cyanation and aminocarbonylation

A Redox-Neutral Catechol Synthesis

Ubiquitous tyrosinase catalyses the aerobic oxidation of phenols to catechols through the binuclear copper centres. Here, inspired by the Fischer indole synthesis, we report an iridium-catalysed tyrosinase-like approach to catechols, employing an oxyacetamide-directed C–H hydroxylation on phenols. This method achieves one-step, redox-neutral synthesis of catechols with diverse substituent groups under mild conditions. Mechanistic studies confirm that the directing group (DG) oxyacetamide acts as the oxygen source. This strategy has been applied to the synthesis of different important catechols with fluorescent property and bioactivity from the corresponding phenols. Finally, our method also provides a convenient route to 18O-labelled catechols using 18O-labelled acetic acid

Antioxidants, Minerals, and Vitamins in Relation to Crohn’s disease and Ulcerative Colitis:A Mendelian Randomization Study

Background Evidence for antioxidants, minerals and vitamins in relation to the risk of Crohn's disease (CD) and ulcerative colitis (UC) is limited and inconsistent. This mendelian randomization (MR) study aimed to examine the causal associations of circulating levels of antioxidants, minerals and vitamins with CD and UC. Methods Single-nucleotide polymorphisms associated with antioxidants (beta-carotene, lycopene and uric acid), minerals (copper, calcium, iron, magnesium, phosphorus, zinc and selenium), and vitamins (folate, vitamins A, B6, B12, C, D, E and K1) were employed as instrumental variables. Genetic associations with CD and UC were extracted from the UK Biobank, the FinnGen study and the International Inflammatory Bowel Disease Genetics Consortium. The inverse variance weighted method and sensitivity analyses were performed. Results Genetically predicted higher lycopene (OR = 0.94, 95% CI: 0.91–0.97), vitamins D (OR = 0.65, 95% CI: 0.54–0.79) and K1 (OR = 0.93, 95% CI: 0.90–0.97) levels were inversely associated with CD risk, whereas genetically predicted higher magnesium (OR = 1.53, 95% CI: 1.23–1.90) levels were positively associated with CD risk. Higher levels of genetically predicted lycopene (OR = 0.91, 95% CI: 0.88–0.95), phosphorus (OR = 0.69, 95% CI: 0.58–0.82), selenium (OR = 0.91, 95% CI: 0.85–0.97), zinc (OR = 0.91, 95% CI: 0.89–0.94), folate (OR = 0.71, 95% CI: 0.56–0.92) and vitamin E (OR = 0.78, 95% CI: 0.69–0.88) were associated with reduced UC risk, whereas genetically predicted high levels of calcium (OR = 1.46, 95% CI: 1.22–1.76) and magnesium (OR = 1.24, 95% CI: 1.03–1.49) were associated with increased risk of UC. Conclusions Our study provided evidence that circulating levels of antioxidants, minerals and vitamins might be causally linked to the development of IBD

A Bioinspired and Biocompatible ortho-sulfiliminyl phenol Synthesis

Synthetic methods inspired by Nature often offer unique advantages including mild conditions and biocompatibility with aqueous media. Inspired by an ergothioneine biosynthesis protein EgtB, a mononuclear non-haem iron enzyme capable of catalysing the C–S bond formation and sulfoxidation, herein, we discovered a mild and metal-free C–H sulfenylation/intramolecular rearrangement cascade reaction employing an internally oxidizing O–N bond as a directing group. Our strategy accommodates a variety of oxyamines with good site selectivity and intrinsic oxidative properties. Combining an O–N bond with an X–S bond generates a C–S bond and an S¼N bond rapidly. The newly discovered cascade reaction showed excellent chemoselectivity and a wide substrate scope for both oxyamines and sulfenylation reagents. We demonstrated the biocompatibility of the C–S bond coupling reaction by applying a coumarin-based fluorogenic probe in bacterial lysates. Finally, the C–S bond coupling reaction enabled the first fluorogenic formation of phospholipids, which self-assembled to fluorescent vesicles in situ

Penaeid shrimp genome provides insights into benthic adaptation and frequent molting

Crustacea, the subphylum of Arthropoda which dominates the aquatic environment, is of major importance in ecology and fisheries. Here we report the genome sequence of the Pacific white shrimp Litopenaeus vannamei, covering similar to 1.66 Gb (scaffold N50 605.56 Kb) with 25,596 protein-coding genes and a high proportion of simple sequence repeats (>23.93%). The expansion of genes related to vision and locomotion is probably central to its benthic adaptation. Frequent molting of the shrimp may be explained by an intensified ecdysone signal pathway through gene expansion and positive selection. As an important aquaculture organism, L. vannamei has been subjected to high selection pressure during the past 30 years of breeding, and this has had a considerable impact on its genome. Decoding the L. vannamei genome not only provides an insight into the genetic underpinnings of specific biological processes, but also provides valuable information for enhancing crustacean aquaculture