56results about How to "Experiment operation is simple" patented technology

The invention belongs to the technical field of micro-fluidic chips, and discloses a hepatic lobule chip which comprises a single cell capture array chip, a micropore array chip and an antibody slide, a capture array on the single cell capture array chip and a micropore array on the micropore array chip are in a polygon shape, perfusion culture solution channels are arranged in the diagonal directions of all vertexes of the polygon, and the capture array and the micropore array are in one-to-one correspondence after being assembled. The liver lobule chip overcomes the dependence of research on spatial heterogeneity of liver cells on precise liver anatomical slices, avoids the defects that the liver slices are difficult to obtain and store, can directly reveal spatial distribution characteristics of secretion activity of the liver cells in the liver lobule, and becomes an ideal tool for spatial heterogeneity secretion of the liver cells. The invention further discloses application of the hepatic lobule chip in hepatic lobule spatial heterogeneity single cell secretion analysis, operation is easy, large experimental instruments are not needed, cost is low, and the hepatic lobule chip is easy to master.

The invention relates to the technical field of plant genetic engineering, and provides an agrobacterium rhizogenes-mediated sunflower transient transformation system and a construction method thereof, sterile conditions and tissue culture are not needed, a vector to be transformed is transferred into agrobacterium rhizogenes, positive strains are cultured and screened, and a dip dyeing solution is prepared; cutting a stem section of the sunflower, and pricking holes near a cut; immersing the stem segments in the dip dyeing liquid for a period of time; taking out and inserting into sterilized vermiculite soil mixed with orobanche coerulescens for rooting to obtain an instantly transformed sunflower plant; the method is easy and convenient to operate and short in period, the expression level of the HaCERK1 gene can be effectively improved, the resistance of sunflowers to orobanche coerulescens infection is enhanced, and the gene function research period is shortened.

The invention relates to a rigid spiro compound and a preparation method and application thereof.The preparation method comprises the steps that 6-methylene-androstane-4-ene-3, 17-diketone (V) is dissolved in a mixed solution of dichloromethane and trifluoroacetic acid, reaction and reduced pressure distillation are conducted at the temperature of 20-25 DEG C, then extraction washing and distillation are conducted, a rigid spiro compound crude product can be obtained, and the rigid spiro compound is obtained. The crude product can be subjected to column chromatography separation and purification to obtain a refined rigid spiro compound (I). By adopting the preparation method, the friction and wear properties of the base oil are remarkably improved, and the base oil has lower friction coefficient and wear scar diameter, and has good application prospect as an antifriction and wear-resistant additive.

The invention relates to the technical field of nano material preparation, in particular to a zinc ion battery cathode material as well as a preparation method and application thereof. The zinc ion battery cathode material provided by the invention has the advantages of uniform shape, uniform size, high first cycle capacity and coulombic efficiency, and good cycle performance. According to the preparation method of the zinc ion battery cathode material provided by the invention, the bimetallic metal organic framework heterogeneous nanosheet material with different doping contents can be prepared by adjusting the concentration of the transition metal ions, and the activity and stability of the material are changed by changing the variety of the transition metal ions. The preparation method disclosed by the invention is also beneficial to large-scale preparation. The method does not need complex equipment, the experimental operation is simple, and macro preparation is easy. The zinc ion battery cathode material provided by the invention has important application in the aspect of electrochemical energy storage, and is helpful for improving the electrochemical performance of various types of battery electrodes.

The invention discloses a visual flexible deformation expansion section test device for a two-dimensional rectangular spray pipe. The visual flexible deformation expansion section test device comprises a spray pipe test section, a transition section, a connection section, a rectification section and an air inlet section which are communicated in sequence, the spray pipe test section comprises a spray pipe mounting frame and a spray pipe main body part, the spray pipe main body part is formed by connecting and enclosing an upper molded panel, a lower molded panel, a left optical glass plate and a right optical glass plate, a glass baffle is arranged on the outer side of the optical glass plate and abuts against the optical glass plate, and the glass baffle is provided with a penetrating opening serving as an observation window; a pressure measuring connector is mounted on the upper molding panel; the lower profile panel is provided with an elastic wall plate mounting port and an elastic wall plate, the lower side surface of the lower profile panel is provided with a cover plate, a cavity is formed between the cover plate and the elastic wall plate, and the cover plate is provided with an air guide hole communicated with the cavity; and a pressure measuring connector, a total pressure measuring device and a temperature measuring connector are mounted on the connecting section. The influence of wall surface ablation movement and vibration of the expansion section on an internal flow field of the spray pipe in the working process of the spray pipe can be observed and recorded.

The invention discloses a preparation method and application of an i-motif-containing DNA surface modified carbon quantum dot, and the carbon dot is prepared by the following steps: synthesizing a carbon dot, and then carrying out DNA modification. The preparation method comprises the following steps: dissolving phenylenediamine in a polymer solution, uniformly mixing, transferring the solution into a polytetrafluoroethylene inner container, putting the inner container into a stainless steel high-pressure kettle, and heating and reacting in a muffle furnace. And after the reaction is finished, cooling a reaction system to room temperature, then polymerizing DNA containing i-motif as a cross-linking agent with CDs, after the polymerization reaction is finished, freeze-drying the solution, taking out the solution, putting the solution into a dialysis bag, and carrying out dialysis purification to obtain DNA-CDs after dialysis is finished. And then carrying out bionic treatment on the MV-DNA-CDs, so as to obtain the MV-DNA-CDs disclosed by the invention. The nano-carrier prepared by the invention is high in yield and good in stability, has responsiveness and targeting property, and can be used for precise treatment of tumors.

The invention relates to the technical field of surface and interface modification of a battery positive electrode material, and discloses a surface and interface modification method of a Prussian blue positive electrode material, which comprises the following steps: mixing sodium citrate and FeSO4. 7H2O in deionized water to prepare a 100mL solution marked as a solution a; the mass ratio of the sodium citrate to the FeSO4. 7H2O is (6-8): (1-3); dissolving sodium citrate and Na4Fe (CN) 6. 10H2O in deionized water to form a 100mL solution, and marking the 100mL solution as a solution b; the mass ratio of the sodium citrate to the Na4Fe (CN) 6. 10H2O is (6-8): (1-2.5). The material is prepared by adopting a coprecipitation method, modification of the surface interface of the Prussian blue positive electrode material is realized by directly utilizing metal titanium ions, and the method is simple and efficient in experimental operation and mild in condition, and has a relatively wide application prospect in actual industrial application.

The invention discloses application of a dual hydrocarbon activation strategy to synthesis of novel non-natural amino acids and polypeptides, belonging to the technical field of organic synthesis. The method comprises the following steps: by taking a lysine derivative and acrolein as starting substrates, reacting for 2 hours at the temperature of 40 DEG C under the action of a rhodium catalyst to obtain a series of non-natural amino acids and polypeptides. The method has the advantages that reaction conditions are mild, raw materials are easy to prepare, only one-step reaction is needed, and experimental operation is simple; antibacterial experiments show that the novel non-natural amino acids and polypeptides have good antibacterial activity on fungi in agriculture and forestry. # imgabs0 #

The invention relates to a method for catalytically synthesizing 2, 4-disubstituted phthalazine 1-(2H)-ketone from 1, 5, 7-triazabicyclo [4.4. 0] dec-5-ene. According to the method, 3-alkenyl phthalide and hydrazine compounds are taken as initial raw materials, TBD which is low in price and easy to obtain is taken as a catalyst, sodium tert-butoxide is taken as alkali, reaction is carried out at room temperature, and the 2, 4-disubstituted phthalazine 1-(2H)-ketone is obtained at high yield. According to the method, the cheap TBD is adopted as the catalyst, the reaction is carried out under the room temperature condition, and compared with a traditional reaction strategy, the economic cost is greatly reduced, the steps are simple, heating and a transition metal catalyst are not needed, operation is convenient, the yield is high, the cost is low, and good economic benefits are achieved.

The application discloses a synthesis method of C3-substituted quinoxaline ketone derivatives and application thereof. A series of C3-substituted quinoxaline ketone derivatives with both terpene and quinoxaline ketone biological activity skeletons are obtained by using N-alkoxy phthalimide and quinoxaline ketone as starting substrates, under the catalysis of a photocatalyst and visible light irradiation, and at a temperature of 55-65 DEG C for 10-15 h. The application has the advantages of stable and easy-to-prepare raw materials, mild reaction conditions, simple experimental operation, good chemical selectivity and functional group tolerance, and is a green chemical synthesis method with good application prospect. The activity experiment results show that the synthesized C3-substituted quinoxaline ketone derivatives have good inhibiting effect on the growth of plant pathogenic fungi.

The utility model discloses a kind of multifunctional lithium battery thermal dynamics experimental device, belong to lithium battery thermal dynamics technical field, the device includes box, fixed frame is placed inside box, fixed frame includes fixed plate, fixed groove is equipped on fixed plate, heating assembly is placed in fixed groove, battery compartment for placing multiple lithium batteries is equipped in heating assembly, the top of heating assembly is connected with protection plate;The top and bottom of heating assembly are equipped with multiple power supply sockets and detection socket, multiple power supply columns and temperature sensing probe are separately equipped in protection plate interior, fixed groove top;Multiple grooves are sequentially equipped on the both sides of fixed groove, rotatable electrode plate is equipped in groove, the inside of electrode plate is equipped with contact block, rotate multiple electrode plate and heat assembly is clamped between multiple electrode plate, and the contact block of electrode plate is all contacted with lithium battery in heating assembly.The utility model can accurately measure multiple data, provide reliable data support for lithium battery thermal dynamics research.

The invention discloses a universal molecular beacon kit for various animal-derived components, and belongs to the technical field of molecular biological detection. Aiming at gene segments with specific structural characteristics in 11 common livestock and poultry animal genomes, the invention designs a composition of a universal primer and a molecular beacon fluorescent probe. The combination can be used for carrying out real-time fluorescent PCR detection and melting curve analysis by using the kit and the method by taking genome DNA of a sample to be detected as a template. By comparing the shape of a melting peak of a detected sample and the characteristic melting temperature (Tm value) of the detected sample, 11 animal-derived components of livestock and poultry can be quickly and accurately identified under the condition of single-tube detection. Technical innovation is achieved in the field of molecular biological detection, an efficient and reliable solution is provided for animal-derived component detection, and the method has important practical value and popularization potential.

The utility model relates to experimental apparatus technical field of ross foam appearance, concretely is a kind of ross foam appearance automation measuring device based on light intensity detection, including conventional ross foam appearance and its both end support, 15 groups wide-angle infrared opposite transmission sensor are arranged in 40mm vertical interval along support outer wall, each group of sensor contains infrared emission tube and receiving tube, arc clamp and its bolt hole and sensor recess for fixing sensor;Signal processing unit, connect sensor for converting light intensity signal into foam height data;Display unit, connect signal processing unit for real-time output measurement result;Power module, power supply for each unit.The utility model on the basis of original ross method operating procedure, through the light transmittance variation of real-time monitoring at different heights by multiple infrared opposite transmission sensors, realized the automation measurement without manual intervention, effectively avoided manual reading error and foam wall hanging interference, improved measurement accuracy and repeatability, simplified experimental operation.

The application discloses a preparation method of 2-cyano-3-hydroxy-2-buten-(4-trifluoromethyl-phenyl)amide, which comprises the following steps: reacting a compound of formula (II) with acetyl chloride or acetic anhydride under the action of a base; wherein the base comprises sodium ethoxide and / or sodium methoxide. In the application, sodium hydride with a relatively high risk coefficient is replaced by sodium alcoholate, the operation difficulty is reduced, the yield is improved compared with sodium hydride, and the application is more suitable for industrial production.

The invention relates to the technical field of gene detection, in particular to a hemophilia virulence gene variation type detection method, which comprises the following steps: comparing sequence reading of third-generation long-reading long sequencing with a reference genome, comparing a part of sequence reading to an F9 gene region and a VWF gene region to obtain a first comparison result, and comparing the first comparison result with a second comparison result to obtain a second comparison result; performing first variation analysis according to the first comparison result, outputting a first analysis result, performing haplotype typing on the F8 gene region to obtain a differential base sequence of an unconventional gene and a highly homologous sequence of the unconventional gene, and comparing the differential base sequence with the residual sequence reading to obtain a second comparison result; and performing second variation analysis according to the second comparison result, and outputting a second analysis result. According to the application, multiple variation types of the hemophilia virulence gene can be screened at the same time, and variation analysis of the F8 gene with homologous gene sequence interference can be solved.

The invention discloses an automatic compensation method for a three-axis magnetic field of an atomic spin inertial measurement device. The method can quickly and accurately compensate the three-axis magnetic field. According to the method, compensation of a Z-direction magnetic field is realized by measuring a three-axis residual magnetic field through a dichotomy, and simultaneous compensation of an X-direction magnetic field and a Y-direction magnetic field is realized through a non-orthogonal decoupling measurement method. The method is reasonable, the experimental operation is simple, the method is suitable for an atomic spin inertial measurement device based on an alkali metal electron spin and inert gas nuclear spin coupling ensemble, the three-axis magnetic field can be rapidly, accurately and automatically compensated in real time, a basis is provided for development of a high-precision atomic spin inertial measurement device, and the workload of device debugging is greatly reduced.

The invention belongs to the technical field of friction experiment equipment, and relates to a device and a method for testing friction of a prepreg interface at any fiber laying angle. The device comprises a first clamping assembly used for fixing a first prepreg layer, a second clamping assembly used for fixing a second prepreg layer and a third material clamping assembly used for clamping a third prepreg layer, and the third material clamping assembly is clamped between the first clamping assembly and the second clamping assembly. The material clamping assembly comprises a material clamping part and a connecting part; the material clamping part comprises a material winding body and a pressing plate, and the material winding body is wrapped with the third prepreg layer; the material winding body comprises a middle clamping plate and a material winding block, and the middle clamping plate and the connecting part are located between the two pressing plates; the material winding block penetrates through the two pressing plates and the connecting part, and the two sides of the material winding block protrude out of the two pressing plates. The material winding block is in a regular hexagon shape, and the third prepreg layer is laid on any two opposite sides. The problems of tedious operation and low test efficiency in the prior art are solved.

This utility model discloses a base lens holder, including a clamping rod, a fixed base, a locking plate, and a positioning device connector. One end of the clamping rod is threadedly connected to the fixed base. The locking plate is threadedly connected to the fixed base and is used to change the tightness of the holder. The fixed base is an integral structure, including a first clamping arm and a second clamping arm. The first clamping arm includes a first clamping tip, and the second clamping arm includes a second clamping tip. There is a millimeter gap between the first and second clamping arms, and the first and second clamping tips form a non-closed clamping groove. After the object to be clamped is placed in the clamping groove, it is locked by the locking plate. The clamping groove can be clamped on both sides; the upper part can clamp a microscope, and the lower part can clamp a base lens, making the connection process between the base lens and the microscope very convenient and quick.

The invention discloses a kit for detecting mRNA (messenger Ribonucleic Acid) in E6 / E7 regions of 14 high-risk human papilloma viruses, and relates to the technical field of pathogen detection, and the technical key points are as follows: the kit is used for detecting E6 / E7 mRNA of at least one high-risk HPV, the high-risk HPV comprises HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68 types, and the HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66 and 68 types can be used for detecting the E6 / E7 mRNA of at least one high-risk HPV. The kit comprises a primer probe combination for detecting the 14 high-risk HPVs and a primer probe combination for detecting the reference gene ACTB. By detecting HPV E6 / E7mRNA, the kit can provide higher specificity than traditional DNA detection and reduce false negative results, so that the accuracy of cervical cancer screening is improved, the kit can early recognize high-risk HPV infection, facilitates timely discovery of cervical cancer precancerous lesions and provides possibility for early intervention, and the kit can distinguish at least 14 high-risk HPVs and has good application prospects. Accurate virus genotype information is provided for clinic, and personalized treatment and prognosis evaluation are facilitated.

The invention relates to the field of catalyst processing, and discloses a method for preparing a dibutyl phthalate synthesis catalyst through temperature programming, and the method for preparing a polyacid catalyst through temperature programming comprises the following steps: S1, carrying out thermal analysis on phosphotungstic acid, phosphomolybdic acid and silicotungstic acid; s2, in a dynamic atmosphere, phosphotungstic acid, phosphomolybdic acid and silicotungstic acid are heated within the temperature range of 25-1000 DEG C, and the heating rate is 5-20 DEG C / min; and S3, selecting a product with the best thermal decomposition effect as a catalyst. The method provided by the invention is reasonable in design, the whole preparation process is simple and clear, complex operation steps or expensive equipment is not needed, and the method is suitable for large-scale industrial production. The experimental operation is easy to master, the technical threshold is remarkably reduced, and popularization and application in factories are facilitated.

The invention discloses a method for synthesizing a gem-difluoroolefin compound through conversion of alkane under catalysis of acridine. The gem-difluoroolefin is a multifunctional fluorine-containing synthon and is a core unit structure for improving performance in the fields of medicines, pesticides and materials. According to the method, an alpha-trifluoroolefin compound and various alkanes are taken as raw materials, and gem-difluoroallylation is directly realized under the conditions of acridine, alkali and illumination. The method has the advantages of simple preparation operation and wide substrate applicability, and contains various electron-withdrawing or electron-donating groups and various cyclic heterocyclic or non-heterocyclic alkanes. The method is mild in reaction condition, relatively high in yield and simple in subsequent treatment, and is a green chemical synthesis method with a relatively good application prospect.

The invention discloses a separation process and application of novel dipeptide Flolutsin C with anti-liver injury activity in Chaetotrichum luteo-virens. The specific method comprises the following seven steps: extraction, QuikSep PS medium-pressure chromatography coarse separation, anti-liver injury active component preliminary screening, Megress C18 reversed-phase preparation column preparation, anti-liver injury active component re-screening, ACE Excel C18AR reversed-phase preparation column preparation and anti-liver injury in-vitro activity evaluation. A solvent and a separation material used in the process can be recycled, so that relatively low separation and preparation cost is ensured, and high-pressure preparative chromatographic separation can ensure that the purity of the product is greater than 95%; the activity screening method is simple, and the quality is stable and controllable; the experimental operation is simple, the cost is low, the quality is controllable, and the result is visual and easy to judge; the obtained anti-liver-injury active compound can be used for preparing anti-non-alcoholic fatty liver disease drugs. The preparation process provided by the invention can realize large-scale production.

The present invention provides a Raman fiber laser system for improving the high-order Raman threshold, comprising: a backward multi-mode pump signal combiner, a Raman low-reflection grating, a Raman high-reflection grating and a Raman gain fiber. Based on the experimental structure of the backward multi-mode pump signal combiner, the present invention can integrate the output end of the signal light with the injection end of the pump light, thereby achieving the effect of rapid amplification of the signal light at the pump light injection end, while reducing the effective action distance of the signal light and the high-order Raman, thereby effectively improving the high-order Raman threshold and achieving higher-power signal light output. In the present invention, the signal light output and the pump light injection are in opposite directions, and the remaining pump light and the generated signal light can be effectively separated, reducing the use of splitter components and simplifying the experimental operation.

The invention relates to the technical field of pathogenic bacteria detection, and discloses a primer, a probe and a kit for detecting mycobacterium tuberculosis based on a reference gene and a bacterial gene. According to the technical scheme, an absolute quantitative qPCR technology is optimized and innovated, and a double-fluorescent probe is designed and is used for respectively marking a specific gene and the reference gene of Mtb; and simultaneously determining the copy number of bacterial genes and the copy number of reference genes in the Mtb and macrophage co-culture system by using an absolute quantitative qPCR (quantitative polymerase chain reaction) technology. The optimized technology not only has innovativeness, but also can be used as a direct index for evaluating the anti-tuberculosis effect, and has wide popularization and application prospects in scientific research and even clinical diagnosis of tuberculosis treatment.

The invention belongs to the technical field of photocatalysis, and particularly relates to a CdS thin film material and a preparation method and application thereof.The preparation method comprises the following steps that a cadmium-containing precursor solution is adsorbed on a substrate, impurities are removed, and a cadmium-containing substrate is obtained; placing the cadmium-containing substrate in a sulfur-containing precursor solution, carrying out a precipitation reaction, and removing impurities to obtain a substrate of which the surface contains CdS seed crystals; the cadmium-containing precursor solution and the sulfur-containing precursor solution are mixed, then the substrate containing the CdS seed crystal is added for a hydrothermal reaction, and the CdS film material is obtained.According to the CdS piezoelectric-photoelectric catalytic nano material prepared through the method, the number of electrons and holes on the surface of CdS can be increased, the photocatalytic degradation efficiency of the CdS piezoelectric-photoelectric catalytic nano material is obviously improved, and the photocatalytic performance of the CdS film material is improved. Two functions, namely photovoltaic and piezoelectric properties, are realized on the same CdS film at the same time, so that the piezoelectric and photoelectric effects of a semiconductor can be fused together, and the subject fusion application in the piezoelectric and photovoltaic fields is realized.

The invention relates to a high-selectivity synthesis method of (3S, 4R)-3-(N-benzyl-N-cyclopropyl) aminomethyl-4-hydroxypyrrolidine-1-carboxylic acid benzyl ester, 1-benzyl-3-tert-butyl-4-oxopyrrolidine-1, 3-dicarboxylate is subjected to selective reduction reaction in the presence of a chiral catalyst to obtain (3S, 4S)-3-tert-butyl-4-hydroxypyrrolidine-1, 3-dicarboxylate, and the (3S, 4R)-3-(N-benzyl-N-cyclopropyl) aminomethyl-4-hydroxypyrrolidine-1, 3-dicarboxylate is subjected to high-selectivity synthesis to obtain (3S, 4R)-3-(N-benzyl-N-cyclopropyl) aminomethyl-4- The preparation method comprises the following steps: firstly, preparing (3S, 4R)-3-((benzyl (cyclopropyl) amino) methyl)-4-((aryl formyl) oxy) pyrrolidine-1-carboxylic acid benzyl ester, then sequentially carrying out acid-catalyzed hydrolysis, condensation reaction with cyclopropylamine, reduction reaction and substitution reaction, then carrying out Mitsunobu reaction with para-substituted aryl formic acid to obtain (3S, 4R)-3-((benzyl (cyclopropyl) amino) methyl)-4-((aryl formyl) oxy) pyrrolidine-1-carboxylic acid benzyl ester, and hydrolyzing under base catalysis to obtain a target compound. The synthesis method has the advantages of high yield and high selectivity, and is expected to be used for industrial production.

This invention discloses a method for synthesizing 4,6-bis(trifluoromethyl)-1,3,5-triazabicyclo[3.1.0]hex-2-ene compounds. Using nitrile compounds and diacaridine as raw materials, the method utilizes photo-induced decomposition of diacaridine to efficiently construct the target azabicyclo skeleton. This method features mild reaction conditions and a simple synthetic route. Furthermore, it exhibits broad functional tolerance, mild reaction conditions, high yield, and simple post-processing, making it a promising green chemical synthesis method. The novel skeleton can serve as a novel bioisostere, overcoming the bottlenecks of limited existing skeleton structures and high synthetic difficulty, providing technical support for drug molecule optimization and new drug development.

The invention belongs to the field of synthesis of fine chemical intermediates, and discloses a multi-site substituted bromopyrene intermediate and a derivative, a preparation method and application thereof. The molecular structural formula of the bromopyrene intermediate is # imgabs0 #, wherein X1, X2 and X3 are bromine atoms or H; and X1, X2 and X3 are not H at the same time. R1 is an alkane having 1 to 90 carbon atoms, a heterocyclic alkane having 1 to 90 carbon atoms, a substituted aromatic hydrocarbon having 5 to 90 carbon atoms, an aryloxy group having 5 to 90 carbon atoms, an aromatic amine having 5 to 90 carbon atoms, a boron aromatic hydrocarbon having 5 to 90 carbon atoms, or an aromatic heterocyclic group having 5 to 90 carbon atoms. The prepared pyrenyl luminescent material can effectively improve the solubility of target molecules, and is applied to the fields of organic luminescent devices, organic photovoltaic devices, perovskite solar devices, fluorescent falsification prevention, thermal response stimuli response, biological imaging and the like.

The present invention discloses an aryl iodine catalyst containing axial chirality and central chirality, a preparation method and use thereof, and an application thereof in the α-position sulfonyloxylation reaction of propiophenone and its derivatives. The aryl iodine catalyst containing axial chirality and central chirality has a structure of the general formula (I). The aryl iodine catalyst containing axial chirality and central chirality provided by the present invention catalyzes the α-position sulfonyloxylation asymmetric synthesis reaction of propiophenone and its derivatives under the co-oxidation effect of an oxidant, exhibits good yield, good to excellent enantioselectivity and good reaction substrate universality, and has good industrial application prospects. The present invention belongs to the field of asymmetric synthetic chemistry.