72 results about "Semicarbazide" patented technology

The present invention relates to novel compounds which are capable of inhibiting semicarbazide-sensitive amine oxidase and myeloperoxidase. These compounds are useful for the treatment of a variety of inflammatory indications, e.g., autoimmune diseases, respiratory disease, fibrosis, vasculitis, neurological diseases or disorders, and the complications resulting from infectious disease, obesity, diabetes / metabolic syndrome and / or cardiovascular disease in human subjects as well as in pets and livestock. In addition, the present invention relates to pharmaceutical compositions containing these compounds, as well as various uses thereof.

The invention discloses a preparation method of a high-purity ultra-clean hydroxylamine aqueous solution. A four-stage purification process comprises the following steps: 1) low-temperature chelation-ceramic membrane metal removal; 2) molecular sieve membrane rectification decomposition prevention; 3) pulse electrodialysis reversal deep desalination; and 4) gradient filtration terminal refining. According to the preparation method of the high-purity ultra-clean hydroxylamine aqueous solution, a low-temperature molecular sieve membrane rectification technology is adopted, hydroxylamine liquid-phase thermal decomposition is avoided through a vapor phase separation mechanism, and the decomposition rate is reduced to 1t from 15% of a traditional process; the method comprises the following steps of: removing metal through chelation-electrodialysis synergistically, ensuring that Fe and Cu ion residues are less than or equal to 0.05 ppb through a thiosemicarbazide-bipolar membrane system, ensuring the nitrogen environment in the whole process, ensuring that the dissolved oxygen is less than or equal to 5ppb, replacing liquid phase distillation with molecular sieve membrane vapor phase separation, solving hydroxylamine liquid phase thermal decomposition, and breaking through the trace metal removal limit by combining thiosemicarbazide-bipolar membrane synergistically removing impurities. And then through nanoscale terminal filtration, the metal / particle control reaches ppb-level limit which is superior to the SEMI standard, and double spanning of quality and cost is realized.

The present invention relates to the field of the preparation of polyurethane elastic fibers, and relates to a preparation method for a bio-based polyurethane elastic fiber, comprising: preparing polyether polyol from sucrose, glycerol, dimethylamine and propylene oxide; adding a solvent, i.e., N,N-dimethylacetamide, and polyether polyol and polyisocyanate into a reaction tank, and adding p-Toluenesulfonyl semicarbazide and aluminum methylenebis(2,4-di-tert-butylphenoxy) phosphate to prepare a spinning solution; and subjecting the spinning solution to spinning and oil application by means of dry spinning technology to obtain the bio-based polyurethane elastic fiber. The present invention ensures that the properties of polyurethane elastic fibers do not deteriorate or are partially enhanced, while the cost and performance advantages are achieved.

The invention discloses a natural plant-based spinning yarn and a preparation method thereof, and relates to the technical field of spinning yarns. When the natural plant-based spinning yarn is prepared, palm fibers are pretreated with a sodium chlorite solution and a sodium hydroxide solution, and pretreated palm fibers are prepared; reacting the pretreated palm fibers with ammonium dihydrogen phosphate to prepare phosphorylated modified palm fibers; reacting the phosphorylated modified palm fibers with calcium nitrate, diammonium hydrogen phosphate and allylphosphonic acid to grow hydroxyapatite in situ, so as to prepare hydroxyapatite composite palm fibers; 4-allyl thiosemicarbazide reacts with salicylaldehyde to prepare an antibacterial agent intermediate, and the antibacterial agent intermediate is complexed with copper ions to prepare an antibacterial agent; grafting an antibacterial agent and an anti-aging agent on the hydroxyapatite composite palm fibers to prepare modified palm fibers; and spinning the modified palm fiber to obtain the natural plant-based spun yarn. The prepared natural plant-based spinning yarn has the advantages of being high in breaking strength, antibacterial, flame-retardant and anti-aging.

The invention discloses a high-strength anti-crack concrete material and a preparation method thereof, and relates to the technical field of concrete. The prepared high-strength anti-crack concrete material is prepared from Portland cement, river sand, modified basalt fibers, modified polyacrylonitrile fibers, a defoaming agent, a water reducing agent and fly ash. The modified basalt fiber is obtained by reacting pretreated basalt fiber with 4-amino-2-tert-butylphenol and then reacting with 2-pyrazinyl ethanethiol, and the modified basalt fiber is obtained; the modified polyacrylonitrile fiber is obtained by reacting hydrolyzed polyacrylonitrile fiber with thiosemicarbazide, then reacting with 2, 4-difluorobromoacetophenone, then reacting with phosphorus oxychloride and N 'N-dimethylformamide, and then cross-linking with 5, 5'-diamino-2, 2 '-dipyridyl, and the modified polyacrylonitrile fiber is obtained by the following steps: reacting hydrolyzed polyacrylonitrile fiber with thiosemicarbazide, reacting with 2, 4-difluorobromoacetophenone, reacting with phosphorus oxychloride and N' N-dimethylformamide, and cross-linking with 5, 5 '-diamino-2, 2'-dipyridyl. The prepared high-strength anti-cracking concrete material has high strength, anti-aging performance and antibacterial performance.

The invention discloses an iron cluster modified iron-manganese diatomic catalyst as well as a preparation method and application thereof, and relates to the technical field of ammonia preparation through electro-catalysis of nitrate reduction, the preparation method comprises the following steps: (1) in the presence of a template agent and a gelatinizing agent, carrying out coordination reaction on a ligand, an iron source and a manganese source, and drying to obtain an aerogel precursor; and (2) carbonizing, pickling, drying and secondarily carbonizing the aerogel precursor to obtain the iron cluster modified iron-manganese diatomic catalyst. According to the preparation method, a step-by-step coordination-template activation strategy is adopted, semicarbazide hydrochloride is taken as a ligand and is coordinated with a carbon-nitrogen source and iron-manganese metal, a double-template agent is introduced to construct a multi-stage pore channel structure, a three-dimensional network framework is formed through gelation, and the porous carbon-loaded iron cluster modified iron-manganese diatomic catalyst is finally obtained through carbonization, acid pickling and secondary carbonization.

The present invention relates to the technical field of multiphase catalysts, and specifically relates to a carbon-based Cu-Ni dual-atom cluster catalyst, a preparation method thereof, and an application thereof. The preparation method includes the following steps: mixing an aqueous solution of thiosemicarbazide, magnesium chloride hexahydrate, an alkali, a nickel salt, a copper salt, and a saccharide compound, and performing freeze-drying to obtain a precursor; sequentially performing preheating treatment, first pyrolysis, and second pyrolysis on the precursor to obtain a carbon-based Cu-Ni dual-atom catalyst; formulating the carbon-based Cu-Ni dual-atom catalyst into a slurry, adhering it to a current collector, and performing in-situ electrolysis treatment to obtain a carbon-based Cu-Ni dual-atom cluster catalyst. The preparation method of the present invention can not only precisely control the number of metal atoms in the metal atom cluster, but also realize the reconstruction of Cu-Ni dual-atom sites, overcoming the problems that it is difficult to control the size of metal particles and it is difficult to exert the advantages of atomic-level catalysts in the traditional high-temperature carbonization method.

The invention provides a composition for inhibiting tumor growth and a preparation method thereof, and belongs to the technical field of medicines. After selenium is loaded, folic acid is coupled, and folic acid-selenium polysaccharide nanoparticles are prepared; notoginsenoside, curcumin, alizarin and hairyvein agrimony phenolic acid are embedded in pH-sensitive lipidosome, and the pH-sensitive lipidosome is uniformly mixed with folic acid-selenium polysaccharide nanoparticles and semicarbazone compounds to prepare the composition for inhibiting tumor growth. The composition for inhibiting tumor growth prepared by the invention has a relatively good anti-tumor effect, can release active components in a targeted manner at a tumor part, can reverse drug resistance, reduce the dosage of chemical drugs, reduce toxicity and improve patient compliance, is high in bioavailability, and has a wide application prospect.

The present application belongs to the technical field of water treatment, and relates to a heat-sensitive color developing agent F-103 production wastewater treatment method. The present application performs multistage treatment on the wastewater. First, an alkaline chemical separation reaction is performed on the wastewater to remove part of the acidic polar organic matter 3-p-tolylsulfonylureido phenol, p-toluenesulfonic acid and the like in the water. Then, an acid chemical separation reaction is performed to further remove the alkaline polar organic matter intermediate MAPOTs and the like in the water. Subsequently, an adsorption reaction is performed using activated carbon to further remove the organic matter and inorganic impurities in the water. Finally, evaporation and concentration are performed to recover the salt sodium chloride. The wastewater treatment of the present application recovers the salt sodium chloride in the wastewater as a resource under the premise of solving the toxicity problem of the organic matter in the wastewater, and realizes the harmless treatment and the reduction of hazardous waste of the wastewater.

The invention relates to a trifluoro-uracil compound containing a semicarbazide structure and a preparation method and application thereof, and provides the trifluoro-uracil compound containing the semicarbazide structure, and the structure is shown as a formula I; the compound has excellent herbicidal toxicological properties, can be used as a pesticide, and particularly can be used as an active ingredient of a herbicide; when being applied to pesticides, the compound has a wider weed control spectrum, can generate a better killing or preventing and treating effect on various weeds, and shows excellent herbicidal activity; the compound is simple in structure, raw materials are easy to obtain and low in cost, and the compound has higher industrial value.

The invention relates to the technical field of organic polymer auxiliaries, and particularly discloses a fluorine-containing release agent with self-healing performance and a preparation method and application thereof. The release agent is prepared from the following components in parts by weight: 1.0 to 10.0 parts of self-healing fluorine modified organic silicon resin, 0.1 to 2.5 parts of simethicone, 0.001 to 0.05 part of stabilizer and 86.0 to 99.0 parts of organic solvent, the self-healing fluorine modified organic silicon resin is prepared from hydroxyl-terminated polydimethylsiloxane dihydric alcohol, diisocyanate and fluorine modified amino silicone oil. The low surface tension and hydrophobic and oleophobic characteristics of the organic fluorine element are utilized, so that migration of dimethyl silicone oil and abrasion of the release agent are reduced. The organic silicone oil molecules containing active amino react with the organic silicone oil with the terminal isocyanate group to generate a large number of acyl semicarbazide bonds. A large number of hydrogen bonds can be formed among the acyl semicarbazide bonds, reversibility is achieved, and the release agent is endowed with good self-healing performance.

The invention relates to a thermally expandable composition comprising: a) At least one thermoplastic polymer TP and / or at least one solid rubber R and b) At least one polymeric blowing agent BA selected from the group consisting of sulfonyl hydrazide-functionalized polymers, sulfonyl semicarbazide-functionalized polymers, carbamate-functionalized polymers, and ureido carbamate-functionalized polymers, wherein the polymeric blowing agent BA has a number average molecular weight (Mn) determined by gel permeation-chromatography (GPC) using polystyrene 0 as standard of at least 500 g / mol, preferably at least 750 g / mol.

The invention discloses a method for determining the content of semicarbazide in a plastic product, and belongs to the technical field of analytical testing, the method is a spectrophotometric method, and the method specifically comprises the following steps: firstly, carrying out derivatization treatment by adopting benzoyl chloride, and then carrying out absorbance detection at 280nm; compared with a liquid chromatography-mass spectrometry method, the method is faster and more efficient in detection and suitable for rapid detection occasions and checkout rooms with low investment cost requirements, the lowest detection capacity of the method is 0.1 mg / L, most quantitative requirements are met, the pretreatment process is simple, the derivation time is short, the operation process is easy to master, and the method is suitable for industrial production. And the result can be obtained only in about 10 minutes in the conventional detection, so that the timeliness and the safety are very high.

The present invention discloses a semicarbazide derivative and its preparation method and application, which belongs to the technical field of anti-lung cancer targeted drugs. The semicarbazide derivative of the present invention can inhibit the growth of H1299 cells in a dose-dependent manner, but has little toxicity to normal lung epithelial cells BEAS-2B. The semicarbazide derivative of the present invention can significantly inhibit the cloning of non-small cell lung cancer cells A549 and H1299, so it has a significant inhibitory effect on the proliferation of non-small cell lung cancer. The semicarbazide derivative provided by the present invention can inhibit the protein expression of GPX4 in non-small cell lung cancer A549 cells, and by inhibiting the protein expression of GPX4, promote the ferroptosis of non-small cell lung cancer cells, thereby playing a role in suppressing tumors.

The invention discloses a method for detecting nitrofuran metabolites in macrobrachium rosenbergii based on UPLC-MS / MS (Ultra Performance Liquid Chromatography-Mass Spectrometry / Mass Spectrometry) and application of the method, and belongs to the technical field of safety evaluation and detection of aquatic products. According to the method, a macrobrachium rosenbergii sample is pretreated by utilizing a QuECHERS method, nitrofuran metabolites are extracted, and the method comprises the steps of adding acidified acetonitrile for extraction, adding ammonium acetate and sodium chloride for water removal, adding a dispersed solid extraction column for reducing a matrix effect and the like. After the treatment by the QuECHERS method disclosed by the invention, the obtained nitrofuran metabolite does not need to be subjected to a derivatization procedure, and an HILIC hydrophilic chromatographic column can be directly used for carrying out liquid chromatography-mass spectrometry analysis in a positive ion mode so as to detect the nitrofuran metabolite such as semicarbazide and the like. The detection method provided by the invention has the advantages of high sensitivity, strong accuracy, wide applicability and the like, and compared with the traditional detection method, the reagent waste can be avoided, and a large amount of time can be saved.

The invention discloses a fluorescent compound capable of detecting semicarbazide with naked eyes as well as a preparation method and application of the fluorescent compound. The preparation method comprises the following steps: carrying out condensation reaction on diketopyrrolopyrrole and nitrogen-containing aromatic primary amine, carrying out coordination with BF3. Et2O, and carrying out [2 + 2] cycloaddition-counter electrocyclization reaction with tetracyanoethylene to obtain the PPAB compound with the electronic push-pull effect. In an organic solvent, PPAB and semicarbazide are subjected to irreversible chemical reaction, high-sensitivity detection of semicarbazide is achieved, and the method has the advantages of being easy and convenient to operate, rapid in reaction, good in selectivity, capable of achieving colorimetric and fluorescent dual-mode detection and the like.

The currently claimed invention relates to a method for improving the color fastness of a cellulose-based substrate to nitrogen oxides and ozone. The method comprises contacting the cellulose-based substrate with a composition comprising: at least one aminourea compound selected from bis[4-[3-(dimethylamino)ureo]phenyl]methane (I) and 4,4'-hexamethylenebis(1,1-dimethylaminourea) (II); at least one solvent selected from alcohols of formula A, glycol ethers of formula B, glycol ethers of formula C, polyethylene glycol, and water; R 1 -OH-A,R 2 -(OCH2CH2-) n OH-B,R 3 -(OCH2(CH3)CH-) m OH-C, where R 1 Selected from C2-C 10 Straight-chain or branched alkyl groups; R 2 Selected from C1-C6 straight-chain or branched alkyl groups; n is 1, 2 or 3; R 3 Selected from C1-C6 straight-chain or branched alkylene groups; and m is 1 or 2; wherein the cellulose-based substrate is selected from at least one of the following: dyed cellulose-based substrate, printed cellulose-based substrate, and dyed and printed cellulose-based substrate; and (ii) drying.

The invention relates to a polyhydroxymethyl melamine-based PVC (polyvinyl chloride) composite heat stabilizer which is characterized by comprising the following components in percentage by mass: 40-60% of polyhydroxymethyl melamine; 25 to 35% of zinc stearate; 10 to 25% of hydrotalcite; 3-6% of an auxiliary heat stabilizer; the molecular structural formula of the polyhydroxymethyl melamine is shown in the specification, x is 1 or 2, y is 1 or 2, and z is 1 or 2; and the auxiliary heat stabilizer is a beta-diketone type compound or 1, 3-dimethyl-6-aminouracil. The polyhydroxymethyl melamine-based PVC composite heat stabilizer can significantly improve the heat stability of PVC, the initial coloring is slight, and the long-term heat stability is excellent.

The invention relates to the technical field of yoga mat production, in particular to a uniformly foamed yoga mat and a preparation method thereof, polyvinyl chloride resin is used as a main component, and polyformaldehyde resin and polymethyl methacrylate resin are added as reinforcing components; the wear resistance, the elasticity, the heat resistance, the cold resistance and the corrosion resistance of the traditional PVC yoga mat can be improved; moreover, aiming at the mixed raw material of the polyvinyl chloride resin, the polyformaldehyde resin and the polymethyl methacrylate resin, three foaming agents with different decomposition temperatures, namely toluenesulfonyl hydrazide, di (benzenesulfonyl hydrazide) ether and p-toluenesulfonyl semicarbazide, are added, and three stages are set in the foaming stage, so that the foaming performance of the polyvinyl chloride resin, the polyformaldehyde resin and the polymethyl methacrylate resin is improved. Different foaming temperatures and foaming time are controlled in each stage, so that the mixed raw materials can be foamed more sufficiently, the foaming of the foaming materials is ensured to be more uniform, and the quality of the yoga mat is improved.

The invention relates to a process for producing polyurethanes using a component A comprising a polyhydrazide, a polysemicarbazide, a polysulfonyl hydrazide and / or carbodihydrazide, in particular a polyhydrazide, wherein the component A is employed in the form of a mixture C which further comprises a component B comprising a dispersion medium.

The invention relates to a high-temperature-resistant flame-retardant CPVC (chlorinated polyvinyl chloride) composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The high-temperature-resistant flame-retardant CPVC composite material comprises the following components in parts by weight: 100 parts of CPVC resin, 4-7 parts of a stabilizer, 0.4-0.8 part of a lubricant, 5-10 parts of calcium carbonate, 10-12 parts of a plasticizer, 1-5 parts of a high-temperature-resistant modifier and 1-3 parts of a modified flame retardant, the phosphorus element in the modified flame retardant forms phosphate during combustion to isolate oxygen and heat, and the boron element forms a glassy covering layer during combustion to synergistically inhibit the generation of smoke; a nitrogen atom of 1, 3-dimethyl-6-aminouracil in the high-temperature-resistant modifier captures alkyl and peroxy free radicals, and a maleimide group enhances an intermolecular acting force and increases the heat resistance of a molecular chain; the high-temperature-resistant flame-retardant CPVC composite material prepared by the invention not only has good high-temperature-resistant and aging-resistant effects, but also has an excellent flame-retardant effect.

The invention belongs to the technical field of water treatment, and relates to a thermosensitive color developing agent F-103 production wastewater treatment method, which comprises the following steps: carrying out multi-stage treatment on wastewater, firstly carrying out alkaline chemical separation reaction on the wastewater, and removing part of acidic polar organic matters such as 3-p-toluenesulfonyl semicarbazide phenol, p-toluenesulfonic acid and the like in water; then carrying out acidic chemical separation reaction to further remove alkaline polar organic matter intermediates MAPOTs and the like in water; then carrying out adsorption reaction by using activated carbon to further remove organic matters and inorganic impurities in the water; and finally evaporating and concentrating, and recovering salt sodium chloride. According to the wastewater treatment method disclosed by the invention, on the premise of solving the toxicity problem of organic matters in the wastewater, the sodium chloride salt in the wastewater is subjected to resource recovery, and the harmlessness of the wastewater and the reduction of hazardous wastes are realized.

The invention discloses 1-(4-aminophenyl)-3-[(4-aminophenyl) carbamoylamino] urea as well as a preparation method and application thereof. The 1-(4-aminophenyl)-3-[(4-aminophenyl) carbamoylamino] urea product is obtained by reacting p-phenylenediamine and diethyl azodicarboxylate under the action of a catalyst. The method is simple in process, milder in reaction condition, easier to control, high in environmental protection property, low in danger coefficient, high in yield and more suitable for industrial application. The product can interact with carbon black to improve the dispersion of carbon black with high specific surface area, can react with carbon-carbon double bonds in natural rubber to form a stable cross-linked network, improves the anti-reversion performance of a rubber material, and has more important social significance and higher economic value.

The application discloses application of a combined inhibitor of copper-molybdenum mixed concentrate in copper-molybdenum flotation separation. The application firstly carries out fine grinding and medicine removing on the copper-molybdenum mixed concentrate; adds the combined inhibitor to inhibit chalcopyrite during the fine grinding process; then adds a collector and a foaming agent to obtain a molybdenum rough concentrate and a copper rough concentrate through roughing; the molybdenum rough concentrate is obtained after being refined, and the copper rough concentrate is obtained after being scanned. The combined inhibitor comprises thiosemicarbazide and thiolactic acid. The dosages of the water-soluble thiosemicarbazide and the thiolactic acid are 0.2-0.5 kg and 0.1-0.2 kg respectively per ton of the copper-molybdenum mixed concentrate. The application can replace the use of toxic inhibitors to reduce environmental pollution, and significantly improve the flotation separation efficiency of copper and molybdenum, and realize efficient separation of copper and molybdenum concentrates.

The utility model belongs to the technical field of toluenesulfonyl semicarbazide production, and particularly relates to a double-decomposition reaction kettle which comprises an outer kettle body and an inner kettle body, the inner kettle body is fixed inside the outer kettle body, and a first rotating shaft and four second rotating shafts are rotatably connected to the inner kettle body through bearings. One end of each of the first rotating shaft and the four second rotating shafts slidably penetrates through the outer kettle body and extends out of the outer kettle body, and first blades are fixed to the surface of the first rotating shaft at equal intervals. According to the reaction kettle disclosed by the utility model, the vertical stirring shaft I and the four transverse stirring shafts II which are obliquely arranged are arranged in the inner kettle body, so that raw materials in the inner kettle body can be more disordered when being stirred, and the uniformity and sufficiency of material mixing are further improved; the damping structure can reduce the vibration of the reaction kettle during operation, so that the risk of material leakage caused by equipment shaking is reduced, and the noise of the reaction kettle during operation can be reduced.

The invention relates to the field of tuning part electroplating processing, and discloses an electroplating process of a high-voltage tuning resonance rod, which comprises the following steps: S1, pretreatment of the resonance rod; s2, performing soaking treatment on the pretreated resonance rod by using a first treatment agent to obtain a primarily treated resonance rod; s3, pre-copper-plating treatment of the primary treatment resonance rod; s4, the resonance rod subjected to copper pre-plating is soaked with a second treating agent, and a pretreated resonance rod is obtained; s5, silver plating treatment, water washing and drying are conducted on the pretreated resonance rod, and the high-voltage-modulation resonance rod is obtained; the first treatment agent is prepared from sodium lignin sulfonate, hydroxypropyl trimethyl ammonium chloride chitosan and water, and the second treatment agent is prepared from sodium 2-acrylamido-2-methylpropanesulfonate, 4-ethyl-3-thiosemicarbazide, acetylchitosamine, polyethylene glycol and water. The plating layer of the high-voltage resonance adjusting rod has the advantages of being fine and firm, is not prone to being influenced by high-voltage corona under the condition of bearing radio frequency high voltage for a long time, and is good in reliability.

The application discloses a fluorescent compound capable of naked-eye detection of aminourea and a preparation method and application thereof. A PPAB compound with electron push-pull action is obtained through condensation reaction of a pyrrolopyrrolodione and a nitrogen-containing aromatic primary amine, coordination with BF3.Et2O, and [2+2] cycloaddition-anti-electric ring-opening reaction with tetracyanoethylene. In an organic solvent, the PPAB and aminourea perform irreversible chemical reaction, high-sensitivity detection of aminourea is realized, and the application has the characteristics of simple operation, rapid reaction, good selectivity, colorimetric and fluorescent dual-mode detection and the like.

The invention discloses a pasty heat-stable material and application thereof in a transparent plastic hose, and relates to the technical field of plastic pipes. The pasty thermal stable material is prepared by the following steps: pre-dispersing white oil and modified fumed silica to obtain a matrix; and adding the zinc stearate, the calcium stearate, the cerium acetylacetonate, the aminouracil maleic amide pentaerythritol ester, the epoxy tetrahydrophthalate and the pentaerythritol diphosphite distearate into the matrix, so as to obtain the pasty thermal stable material. The preparation method comprises the following steps: adding the zinc stearate, the calcium stearate, the cerium acetylacetonate, the aminouracil maleic amide pentaerythritol ester, the epoxy tetrahydrophthalate and the pentaerythritol diphosphite distearate into the matrix; the pasty heat-stable material prepared by the invention effectively inhibits long-term thermal degradation and color change of PVC, effectively prolongs the initial whiteness, can be widely applied to food-grade, medical-grade and industrial-grade transparent PVC hoses, improves the long-term stability of a PVC system, keeps the optical and physical properties of the transparent plastic hoses, and has a good application prospect. And excellent thermal aging resistance and environmental friendliness are realized.

Thioesters, thiocarbamates, thiocarbazates, semithiocarbazates, peptides, aza-amino acid conjugates, and azapeptides; and a chemoselective and site-specific functionalization protocol of protected thiocarbazates and semithiocarbazates are described. The protocol features the use of Mitsunobu reaction to alkylate specifically the nitrogen atom close to the acylthiol moiety with alcohols to produce protected mono-substituted thiocarbazates that can be stored for months, activated under mild conditions at low temperature using halonium reagents and integrated orthogonally to make substituted semicarbazides that can be used, e.g., as synthons in synthesis of aza-amino acid conjugates, azapeptides and other peptidomimetics. Methods for preparing and using ureases, carbazides, semicarbazides, beta-peptides, azapeptides, and other peptidomimetics and azapeptide conjugates, and uses of ureases, carbazides, semicarbazides, beta-peptides, azapeptides in drug discovery, diagnosis, inhibition, prevention and treatment of diseases are also described.

The invention provides a method for rapidly detecting semicarbazide in a food contact material, which comprises the following steps of: (1) cutting a gasket of a bottle cap of a food contact material container into pieces; (2) weighing a sample, putting the sample into a centrifugal tube, adding an acetic acid solution, and performing ultrasonic extraction; after cooling, centrifuging the centrifugal tube, and taking supernate to another centrifugal tube; (3) adding an internal standard working solution, then adding a 2-nitrobenzaldehyde solution, carrying out uniform vortex mixing, and carrying out light-shielding oscillation in a constant-temperature water bath oscillator; (4) taking out the centrifuge tube, cooling, adding a dipotassium phosphate solution, adjusting the pH value, adding ethyl acetate, carrying out vortex oscillation and centrifugation, transferring supernatant into the glass centrifuge tube, and drying in nitrogen; (5) adding a formic acid aqueous solution to dissolve residues, filtering through a filter membrane, and carrying out mass spectrum detection; (6) making a standard solution curve; the other steps are operated according to the step (3) to the step (5). The detection method disclosed by the invention is high in sensitivity, short in analysis period and high in accuracy, and meets the requirement of rapidly determining the semicarbazide in the food contact material.