Aerobic Oxidative Hydroxylation of Arylboronic Acids under Visible-Light Irradiation without Metal Catalysts or Additives.

Phenols are versatile synthetic intermediates and key structural motifs in many natural products and biologically active compounds. We herein report a visible-light-induced aerobic oxidative hydroxylation of arylboronic acids/pinacol esters using air as oxidant and without using any catalysts and base, etc., additives, providing a green entry to a variety of phenols in a highly efficient and concise fashion. This novel reaction is enabled by photoactivation of an electron donor-acceptor complex, in which THF serves as both the solvent and electron donor. DFT studies indicated that the oxidation process involves a concerted hydrogen abstraction transfer from THF and dehydroxylation of boronic acid undergoing spin crossover from triplet to singlet to produce an active peroxoboronic acid intermidiate. Salient merits of this chemistry include broad substrate scope and excellent functional group tolerance, gram-scale synthesis, and versatile late-stage functionalizations as well as the use of air, visible light, and catalyst- and additive-free conditions. This strategy introduces a novel photoreaction mode with the aid of a solvent, offering a succinct and environmentally sustainable route for synthesizing phenols. The strong practicability and highly efficient access to modifying complex biorelevant molecules bode well for the potential applications of this chemistry in pharmaceutical chemistry.

Total Synthesis and Anti-Inflammatory Evaluation of Osajin, Scandenone and Analogues.

In this study, the total synthesis of osajin, scandenone and their analogues have been accomplished. The key synthetic steps include aldol/intramolecular iodoetherification/elimination sequence reactions and a Suzuki coupling reaction to assemble the tricyclic core, chemoselective propargylation and Claisen rearrangement reactions to obtain natural compounds. In addition, we also designed and synthesized twenty-five natural product analogues. All synthetic compounds were screened for anti-inflammatory activity against tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Collectively, Compound 39e and 39d were considered as promising lead compounds for further development.

miR319 and its target TCP4 involved in plant architecture regulation in Brassica napus.

Plant architecture is a collection of genetically controlled crop productivity and adaptation. MicroRNAs (miRNAs) have been proved to function in various biological processes, but little is known about how miRNA regulates plant architecture in rapeseed (Brassica napus L.). In this study, four small RNA libraries and two degradome libraries from shoot apex of normal and rod-like plants were sequenced. A total of 639 miRNA precursors and 16 differentially expressed miRNAs were identified in this study. In addition, 322 targets were identified through degradome sequencing. Among them, 14 targets were further validated via RNA ligase-mediated 5' rapid amplification of cDNA ends. Transgenic approach showed that increased TCP4 activity in Arabidopsis resulted in premature onset of maturation and reduced plant size along with early flowering and shortened flowering time. miR319-OE lines in Brassica napus exhibited serrated leaves and abnormal development of shoot apical meristem (SAM), which led to the deformed growth of stem and reduced plant height. In conclusion, our study lays the foundation for elucidating miRNA regulate plant architecture and provides new insight into the miR319/TCP4 module regulates plant architecture in rapeseed.

Identification and Fine Mapping of the Candidate Gene Controlling Multi-Inflorescence in Brassica napus.

As a desirable agricultural trait, multi-inflorescence (MI) fulfills the requirement of mechanized harvesting and yield increase in rapeseed (Brassica napus L.). However, the genetic mechanism underlying the multi-inflorescence trait remain poorly understood. We previously identified a difference of one pair of dominant genes between the two mapping parental materials. In this study, phenotype and expression analysis indicated that the imbalance of the CLAVATA (CLV)-WUSCHEL (WUS) feedback loop may contribute to the abnormal development of the shoot apical meristem (SAM). BnaMI was fine-mapped to a 55 kb genomic region combining with genotype and phenotype of 5768 BCF1 individuals using a traditional mapping approach. Through comparative and expression analyses, combined with the annotation in Arabidopsis, five genes in this interval were identified as candidate genes. The present findings may provide assistance in functional analysis of the mechanism associated with multi-inflorescence and yield increase in rapeseed.

Combined Transcriptomics and Metabolomics Analysis Reveals the Molecular Mechanism of Salt Tolerance of Huayouza 62, an Elite Cultivar in Rapeseed (Brassica napus L.).

Soil salinity is one of the most significant abiotic stresses affecting crop yield around the world. To explore the molecular mechanism of salt tolerance in rapeseed (Brassica napus L.), the transcriptome analysis and metabolomics analysis were used to dissect the differentially expressed genes and metabolites in two rapeseed varieties with significant differences in salt tolerance; one is an elite rapeseed cultivar, Huayouza 62. A total of 103 key differentially expressed metabolites (DEMs) and 53 key differentials expressed genes (DEGs) that might be related to salt stress were identified through metabolomics and transcriptomics analysis. GO and KEGG analysis revealed that the DEGs were mainly involved in ion transport, reactive oxygen scavenging, osmotic regulation substance synthesis, and macromolecular protein synthesis. The DEMs were involved in TCA cycle, proline metabolism, inositol metabolism, carbohydrate metabolic processes, and oxidation-reduction processes. In addition, overexpression of BnLTP3, which was one of the key DEGs, could increase tolerance to salt stress in Arabidopsis plants. This study reveals that the regulation mechanism of salt tolerance in rapeseed at the transcriptome and metabolism level and provides abundant data for further in-depth identification of essential salt tolerance genes.