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Thiosemicarbazones
In organic chemistry, a semicarbazone is a derivative of imines formed by a condensation reaction between a ketone or aldehyde and semicarbazide. They are classified as imine derivatives because they are formed from the reaction of an aldehyde or ketone with the terminal -NH2 group of semicarbazide, which behaves very similarly to primary amines. Formation ;For ketones :H2NNHC(=O)NH2 + RC(=O)R → R2C=NNHC(=O)NH2 ;For aldehydes :H2NNHC(=O)NH2 + RCHO → RCH=NNHC(=O)NH2 For example, the semicarbazone of acetone would have the structure (CH3)2C=NNHC(=O)NH2. Properties and uses Some semicarbazones, such as nitrofurazone, and thiosemicarbazones are known to have anti-viral and anti-cancer activity, usually mediated through binding to copper or iron in cells. Many semicarbazones are crystalline solids, useful for the identification of the parent aldehydes/ketones by melting point analysis. A ''thiosemicarbazone'' is an analog of a semicarbazone which contains a sulfur atom in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thiosemicarbazone
A thiosemicarbazone is an organosulfur compound with the formula H2NC(S)NHN=CR2. Many variations exist, including those where some or all of the N''H'' centers are substituted by organic groups. Thiosemicarbazones are usually produced by condensation of a thiosemicarbazide with an aldehyde or ketone: : H2NC(S)NHNH2 + O=CR2 → H2NC(S)NHN=CR2 + H2O In terms of their chemical structures, the CSN3 core atoms are coplanar. Occurrence and applications Some thiosemicarbazones have medicinal properties, e.g. the antiviral metisazone and the antibiotic thioacetazone. Thiosemicarbazones are also widely used as ligands in coordination chemistry A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' .... The affinity of thiosemicarbazones for metal ions is exploited in controlling iron o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semicarbazone
In organic chemistry, a semicarbazone is a derivative of imines formed by a condensation reaction between a ketone or aldehyde and semicarbazide. They are classified as imine derivatives because they are formed from the reaction of an aldehyde or ketone with the terminal -NH2 group of semicarbazide, which behaves very similarly to primary amines. Formation ;For ketones :H2NNHC(=O)NH2 + RC(=O)R → R2C=NNHC(=O)NH2 ;For aldehydes :H2NNHC(=O)NH2 + RCHO → RCH=NNHC(=O)NH2 For example, the semicarbazone of acetone would have the structure (CH3)2C=NNHC(=O)NH2. Properties and uses Some semicarbazones, such as nitrofurazone, and thiosemicarbazones are known to have anti-viral and anti-cancer activity, usually mediated through binding to copper or iron in cells. Many semicarbazones are crystalline solids, useful for the identification of the parent aldehydes/ketones by melting point analysis. A ''thiosemicarbazone'' is an analog of a semicarbazone which contains a sulfur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbazide
In chemistry, a carbazide is a functional group with the general formula . They can be derived from the condensation of carbonic acid with a hydrazine. Carbohydrazide is the simplest carbazide, with another common carbazide being diphenylcarbazide, which is used as an analytical reagent. Diphenylcarbazide forms an intense blue color with chromium in the hexavalent state. It has an absorptivity coefficient of about 3400. That means very small amounts of chromium can be detected; 25 micrograms in 25 mL of solution are too dark to read on a spectral device, so concentrations well below that can be detected. Thiocarbazide The sulfur analog is called a thiocarbazide, of which thiocarbohydrazide is the simplest example. Carbazone and thiocarbazone A carbazone is a partially oxidized carbazide with the general formula . The sulfur analog is called a thiocarbazone, of which dithizone is an example. See also * Semicarbazide * Semicarbazone In organic chemistry, a semicarbazone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbazone
In chemistry, a carbazide is a functional group with the general formula . They can be derived from the condensation reaction, condensation of carbonic acid with a hydrazine. Carbohydrazide is the simplest carbazide, with another common carbazide being diphenylcarbazide, which is used as an analytical reagent. Diphenylcarbazide forms an intense blue color with chromium in the hexavalent state. It has an Molar absorptivity, absorptivity coefficient of about 3400. That means very small amounts of chromium can be detected; 25 micrograms in 25 mL of solution are too dark to read on a spectral device, so concentrations well below that can be detected. Thiocarbazide The sulfur structural analog, analog is called a thiocarbazide, of which thiocarbohydrazide is the simplest example. Carbazone and thiocarbazone A carbazone is a partially oxidized carbazide with the general formula . The sulfur analog is called a thiocarbazone, of which dithizone is an example. See also * Semicarbazide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with the chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature. Sulfur is the tenth most abundant element by mass in the universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and ancient Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum.. Downloahere Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melting Point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilibrium, equilibrium. The melting point of a substance depends on pressure and is usually specified at a Standard temperature and pressure, standard pressure such as 1 Atmosphere (unit), atmosphere or 100 Pascal (unit), kPa. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of substances to Supercooling, supercool, the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact, the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the #Melting point measurements, melting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most abundant element in the Earth's crust, being mainly deposited by meteorites in its metallic state. Extracting usable metal from iron ores requires kilns or furnaces capable of reaching , about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BC and the use of iron tools and weapons began to displace copper alloys – in some regions, only around 1200 BC. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, stainless steel, cast iron and special steels, are by far the most common industrial metals, due to their mechan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable, unalloyed metallic form. This means that copper is a native metal. This led to very early human use in several regions, from . Thousands of years later, it was the first metal to be smelted from sulfide ores, ; the first metal to be cast into a shape in a mold, ; and the first metal to be purposely alloyed with another metal, tin, to create bronze, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemotherapy
Chemotherapy (often abbreviated chemo, sometimes CTX and CTx) is the type of cancer treatment that uses one or more anti-cancer drugs (list of chemotherapeutic agents, chemotherapeutic agents or alkylating agents) in a standard chemotherapy regimen, regimen. Chemotherapy may be given with a cure, curative intent (which almost always involves combinations of drugs), or it may aim only to prolong life or to Palliative care, reduce symptoms (Palliative care, palliative chemotherapy). Chemotherapy is one of the major categories of the medical discipline specifically devoted to pharmacotherapy for cancer, which is called ''oncology#Specialties, medical oncology''. The term ''chemotherapy'' now means the non-specific use of intracellular poisons to inhibit mitosis (cell division) or to induce DNA damage (naturally occurring), DNA damage (so that DNA repair can augment chemotherapy). This meaning excludes the more-selective agents that block extracellular signals (signal transduction) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiviral Drug
Antiviral drugs are a class of medication used for treating viral infections. Most antivirals target specific viruses, while a broad-spectrum antiviral is effective against a wide range of viruses. Antiviral drugs are a class of antimicrobials, a larger group which also includes antibiotic (also termed antibacterial), antifungal and antiparasitic drugs, or antiviral drugs based on monoclonal antibodies. Most antivirals are considered relatively harmless to the host, and therefore can be used to pharmacotherapy, treat infections. They should be distinguished from virucides, which are not medication but deactivate or destroy virus particles, either inside or outside the body. Natural virucides are produced by some plants such as eucalyptus and Australian tea trees. Medical uses Most of the antiviral drugs now available are designed to help deal with HIV, Herpesviridae, herpes viruses, the hepatitis B and Hepatitis C, C viruses, and Influenzavirus A, influenza A and Influenzavirus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrofurazone
Nitrofurazone (INN, trade name Furacin) is an antimicrobial organic compound belonging to the nitrofuran class. It is most commonly used as a topical antibiotic ointment. It is effective against gram-positive bacteria, gram-negative bacteria, and can be used in the treatment of trypanosomiasis. Its use in medicine has become less frequent, as safer and more effective products have become available. Nitrofurazone is listed under California Prop 65, and has demonstrated clear evidence to be mutagenic and carcinogenic during animal studies, and has been discontinued for human use in the USA. The substance is pale yellow and crystalline. It was once widely used as an antibiotic for livestock. Medical uses Human use Nitrofurazone was previously available as a prescription in the U.S., and was indicated as a topical solution, topical cream, or topical ointment for the treatment of bacterial skin infections, wounds, burns, and ulcers. It was also used as a prophylactic meas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
