八步连续流全合成维生素B_(1)工艺研究

Vitamin B_(1) is widely applied in the healthcare and food industry as an antineuritic and antioxidant to maintain the normal functioning of nerve conduction,the heart,and the gastrointestinal tract.This study reports on an integrated eight-step continuous-flow synthesis of vitamin B_(1) from commercially available 2-cyanoacetamide.The proposed continuous-flow process is based on advances in chemistry,engineering,and equipment design,and affords improved performance and safety compared with batch-mode manufacturing.Several challenges were precisely investigated and controlled,including mixing,unexpected clogging,solvent switches,an exothermic reaction,and the prevention of side reactions,using various micro-channel flow reactors,mixers,separators,and continuous filters.Vitamin B_(1) was produced with a separated yield of 47.7% and high purity,with a total residence time of about 3.5 h.This eight-step continuous-flow protocol enables technology involving up to six of the key principles of green chemistry.Hence,the application of flow technology is of paramount importance for improving security,reducing waste,and,in particular,improving the efficiency of batch operations that require several days for manufacturing.

瑞德西韦核碱基单元的连续流合成

本研究采用五步连续流法合成了抗病毒药物瑞德西韦的碱基单元7-溴吡咯[2,1-f][1,2,4]三嗪-4-胺。采用间歇式合成化学方法,以吡咯为原料,通过序流操作成功制备了7-溴吡咯[2,1-f][1,2,4]三嗪-4-胺。在最优流动条件下,7-溴吡咯[2,1-f][1,2,4]三嗪-4-胺的分离率为14.1%,总停留时间为79min,通量为2.96 g·h^(-1)。总停留时间明显短于批处理过程所消耗的总时间(>26.5 h)。在流动中,有利于高放热的Vilsmeier-Haack反应和N-胺化反应,这些反应涉及危险和不稳定的中间体、氧化液-液两相转化以及需要严格低温条件的溴化反应。这种合成的显著特点是,通过部署专用设备和分离单元,将后处理程序完全集成到反应序列中,从而形成一个流线型的连续流系统,最大限度地提高了整体工艺效率。该方法是一种更环保、更可持续的高效、安全制备这种碱基单元的方法。

Genome-wide Analysis of a Plant AT-rich Sequence and Zinc-binding Protein (PLATZ) in Triticum Aestivum

Plant AT-rich sequence and zinc-binding protein(PLATZ)is a plant transcription factor that has been studied in corn.PLATZ can non-specifically bind to sequences rich in A/T bases to induce transcriptional repression.It is involved in the regulation of dehydration tolerance in seeds.In this study,we performed bioinformatics analysis to identify and characterize wheat PLATZ(TaPLATZ)genes.We identified 49 wheat PLATZ genes by searching the wheat genome by using known PLATZ gene sequences from rice,Arabidopsis,and maize.Phylogenetic analysis on PLATZ gene sequences from different species was performed.We found that PLATZs could be divided into three groups.The chromosome(chr)distribution analysis revealed that the 49 identified wheat PLATZ genes are distributed in 15 chrs.Gene structure and motif analyses indicated that most PLATZ genes possess conserved exon/intron arrangements and motif compositions.Our analysis of transcriptional data indicated that several wheat PLATZ genes may play an important role in abiotic stress resistance given that they are expressed under salt stress.The results of qRT-PCR further confirmed that TaPLATZ is involved in plant abiotic stress and is also related to the cell differentiation of plant tissues.Our results lay the foundation for further studies on the function of the wheat PLATZ gene family.

Change of 3 Kinds of Enzyme Activity and Soluble Sugar in 3 Chinese Cabbage Varieties with Different Resistance Level During the Process of Plasmodiophora brassicae Infecting Their Roots

There are different levels of resistance in Chinese cabbage varieties against clubroot.The content of catalase(CAT),peroxidase(POD),phenylalanin ammonia-lyase(PAL),Super Oxide Dismutase(SOD)and soluble sugar activities of 3cultivars with different clubroot-resistant levelswere detected after inoculation in this study.The results suggest that the changing rates of CAT,PAL and SOD contents of resistance cultivars after inoculation were higher than those of susceptible cultivars(Baigengbaiye>Zaobaicaitai>Huangjinxiaobaicai);the POD activities of resistance cultivars reached a peak on an earlier day than those of susceptible cultivars;the increasing rate of soluble sugar of susceptible cultivars was higher than that of the resistance cultivars,and ended with two peaks.Therefore,the four enzymes(CAT,POD,PAL and SOD)and soluble sugar may be used as physiological and biochemical reference indexes for the resistance identification to clubroot after inoculation with P.brassicae.

A solvent-free,selective liquid phase hydrogenation of nitroarenes to aniline in slurry bubble mode on porous NiMo bimetallic catalyst

NiMo bimetallic catalysts were prepared by a solid reaction method.On the NiMo catalyst,the selective liquid phase hydrogenation of nitrobenzene to aniline was achieved in slurry bubble mode.And the high yields(98.9%)were obtained under the conditions of 80℃,solvent-free and atmospheric pressure.The effect of Mo on the catalytic behavior of Ni based catalyst was investigated.The characterization displayed that the inclusion of Mo could improve the specific surface area and pore volume,and the solid reaction method made metal Mo enrichment on the surface of catalyst.These two aspects should be responsible for excellent catalytic performance of NiMo catalyst.In sum,we described a simple and efficient NiMo catalyst and provided a facile and green procedure for liquid phase hydrogenation of nitrobenzene to aniline.

Wheat Lysin-Motif-Containing Proteins Characterization and Gene Expression Patterns under Abiotic and Biotic Stress

Lysin motif(LysM)-containing proteins(LYPs)are important pattern recognition receptors in plants.However,the evolutionary history and characteristics of LYP genes remain largely unclear in wheat.In this study,62 LYPs were identified at genome wide in wheat.Based on phylogenetic and domain analysis,wheat LYPs were classified into 6 subgroups(group LysMe,LysMn,LYP,LYK,LysMFbox).Syntenic analysis showed the evolution of LYP genes in wheat.RNA-seq data showed that 22 genes were not expressed at any tissue or stress stimulation period.Some LYP and LYK genes were tissue-or stage-specific.The majority of TaLYK5s,TaLYK6s,TaLYP2s and TaLysMns genes were induced under chitin,flg22 and fungal treatment.qRT-PCR analysis showed that 4 genes were upregulated during Puccinia triticina infection with a peak at 18 h post inoculation.Our findings suggested that wheat LYPs may have specific roles in response to fungal infection and provided insights into the function and characteristics of wheat LYP genes.

Studies on the Correlation between Germination and cAMP Content of Different Color Chlamydospores in Ustiloginoidea virens

Ustilaginoidea virens is the causal agent of a serious disease of rice. To reveal the relationship between germination and the 3'-5'-cyclic adenosine monophosphate(c AMP) content from the dormant(black or green-black) and non-dormant(yellow)chlamydospore in Ustiloginoidea virens,this study adopts ultrasonic-bath method and high-performance liquid chromatography(HPLC) method, for extraction c AMP content of the different color chlamydospore. The results demonstrated that, as for the freshly chlamydospores collected from the false smut balls during their germination, c AMP content of yellow chlamydospore appeared a slight growth during 0-12 h, and showed a rapid declining as the germination time extended(12-48 h). Above all, in yellow chlamydospores, the germination rate and the content of c AMP presented a very notably negative correlation(|r|=0.861 9>r0.01=0.834), but the correlation between germination rate and content of c AMP was not obvious in black chlamydospores. The germination rate and the content of c AMP presented a notably positive correlation under different storage period(0, 2, 4, 6, 8,10 months) of the two color chlamydospores(the yellow of chlamydospore: |r | = 0.785 1 > r0.05= 0.707; the black of chlamydospore: |r| = 0.957 9 > r0.05= 0.707).

Photo-induced 1,2-aryl migration of 2-chloro-1-arylpropanone under batch and flow conditions:Rapid,scalable and sustainable approach to 2-arylpropionic acids

We report the photo-mediated 1,2-aryl migration of 2‑chloro-1-arylpropanones to 2-arylpropionic acids using HCOONa as an acid scavenger.This pragmatically focused study obviates the multiple-step sequence in the industrially employed,ZnO-promoted rearrangement strategy,and offers rapid access to various 2-arylpropionic acids under environmentally friendly conditions.Furthermore,the successful transfer of this batch photochemistry to a continuous flow platform led to improved scalability and enabled the gram-scale synthesis of loxoprofen.

硝基芳烃与醇还原胺化:催化剂和催化机制

胺类化合物由于其化学结构和性质上的特点,在合成药物、染料和精细化学品等方面有着重要的应用。胺类化合物的合成方法很多,其中硝基芳烃与醇还原胺化反应由于可以“一锅”法将性质稳定、来源广泛的硝基芳烃、醇转化为各类胺类化合物,且无需提供额外的氢源,从而成为研究的热点。本文即以硝基芳烃与醇还原胺化反应路径为主线,从催化剂及其催化机制两方面对硝基芳烃与醇还原胺化反应的研究进展进行综述,分别对已开发的贵金属催化剂、光催化剂及一些其他类型催化剂作了介绍,重点阐述了催化剂的催化性能、底物适用范围和催化机制。尽管目前各类催化体系都已取得较大的进展,但在一定程度上依然存在着催化剂成本高,底物适应性窄,需要大量使用碱性助剂、溶剂、供氢试剂等问题。基于以上问题,本文指出硝基芳烃与醇还原胺化应重点发展绿色高效、廉价、普适性好、通用性强的催化体系;同时,还要系统地对各种催化剂的催化机制进行深入的研究,为催化体系的开发提供指导。

Improving the positional adaptability:structurebased design of biphenyl-substituted diaryltriazines as novel non-nucleoside HIV-1 reverse transcriptase inhibitors

In order to improve the positional adaptability of our previously reported naphthyl diaryltriazines(NP-DATAs),synthesis of a series of novel biphenyl-substituted diaryltriazines(BP-DATAs)with a flexible side chain attached at the C-6 position is presented.These compounds exhibited excellent potency against wild-type(WT)HIV-1 with EC50 values ranging from 2.6 to 39 nmol/L and most of them showed low nanomolar anti-viral potency against a panel of HIV-1 mutant strains.Compounds 5 j and 6 k had the best activity against WT,single and double HIV-1 mutants and reverse transcriptase(RT)enzyme comparable to two reference drugs(EFV and ETR)and our lead compound NP-DATA(1).Molecular modeling disclosed that the side chain at the C-6 position of DATAs occupied the entrance channel of the HIV-1 reverse transcriptase non-nucleoside binding pocket(NNIBP)attributing to the improved activity.The preliminary structure-activity relationship and PK profiles were also discussed.

Regulation of impedance matching feature and electronic structure of nitrogen-doped carbon nanotubes for high-performance electromagnetic wave absorption

In this study,we developed a facile method to fabricate three-dimensional(3D)structures composed of FeNi alloy nanoparticles encapsulated in N-doped carbon nanotubes that grafted on the SiO_(2) spheres(Fe_(x)Ni_(y)@NCNT@SiO_(2))for electromagnetic wave(EMW)absorption.The experimental results suggest that the impedance matching characteristic can be tuned by the introduction of SiO_(2) spheres in the 3D structure.Density functional theory(DFT)calculations showed that the introduction of Ni improved the polarization and conductive losses of the Fe_(x)Ni_(y)@NCNT@SiO_(2).As a result,the optimal 3D structure exhibits excellent EMW absorption property with a reflection loss and effective absorption bandwidth are-49.39 dB and 4.32 GHz,respectively,even though the matching thickness is only 1.6 mm,superior to most magnetic carbon-based composites.Thus,our current approach opens up an effective way to the development of low-cost,high-performance EMW absorbers.

Artificial neuron synapse transistor based on silicon nanomembrane on plastic substrate

Silicon nanomembrane（SiNM）transistors gated by chitosan membrane were fabricated on plastic substrate to mimic synapse behaviors.The device has both a bottom proton gate（BG）and multiple side gates（SG）.Electrical transfer properties of BG show hysteresis curves different from those of typical SiO2 gate dielectric.Synaptic behaviors and functions by linear accumulation and release of protons have been mimicked on this device：excitatory post-synaptic current（EPSC）and paired pulse facilitation behavior of biological synapses were mimicked and the paired-pulse facilitation index could be effectively tuned by the spike interval applied on the BG.Synaptic behaviors and functions,including short-term memory and long-term memory,were also experimentally demonstrated in BG mode.Meanwhile,spiking logic operation and logic modulation were realized in SG mode.

New insights in the battle between wheat and Puccinia striiformis

Wheat stripe rust caused by Puccinia striiformis f.sp.tritici(Pst)poses a great threat to wheat production worldwide.The rapid change in virulence of Pst leads to a loss of resistance in currently resistant wheat cultivars,which results in frequent disease epidemics.Therefore,a major focus is currently placed on investigating the molecular mechanisms underlying this rapid variation of pathogenicity and coevolving wheat resistance.Limited by the lack of a system for stable transformation of Pst and the difficulties in wheat transformation,it is not easy to generate deeper insights into the wheat-Pst interaction using established genetic methods.Nevertheless,considerable effort has been made to unravel the wheat-Pst interaction and significant progress is being made.Histology and cytology have revealed basic details of infection strategies and defense responses during wheat-Pst interactions,identified cellular components involved in wheat-Pst interactions,and have helped to elucidate their role in the infection process or in plant defense responses.Transcriptome and genome sequencing has revealed the molecular features and dynamics of the wheat-Pst pathosystem.Extensive molecular analyses have led to the identification of major components in the wheat resistance response and in Pst virulence.Studies of wheat-Pst interactions have now entered a new phase in which cellular and molecular approaches are being used.This review focuses on the cellular biology of wheat-Pst interactions and integrates the emerging data from molecular analyses with the histocytological observations.

Flow chemistry in the multi-step synthesis of natural products

The total synthesis of natural products is constantly facing many challenges derived from the complexed chemical structures,the lengthy synthetic routes,the time-consuming workup procedures and the large environmental footprint.In the past two decades,performing chemical transformations in continuous flow using various types of microreactors and in-line auxiliary technologies have been demonstrated effectively in respects of enhanced re-action yield and selectivity,excellent reproducibility and easy scale-up,safe proceeding hazardous reaction.And the rapid synthesis of natural products,which has been enabled in continuous flow based upon the significant improvement of overall yield within a short residence time via processing intensification and systematic auto-mation,is essential to furnish sufficient quantity for the bioactivity investigation of structural diversity modifi-cation,structure-activity relationship during drug discovery and the increasing consumption of medical treatment.In this review,the multi-step continuous flow synthesis of natural products is highlighted to provide a comprehensive recognization on the intrinsic merits of flow chemistry for organic chemists to purposefully develop the flow synthetic approaches of natural products in the future.