|
Tetrazole
A tetrazole is a chemical synthesis, synthetic organic heterocyclic compound, consisting of a 5-member ring of four nitrogen atoms and one carbon atom. The name tetrazole also refers to the parent compound - a whitish crystalline powder with the formula CH2N4, of which three isomers exist. Structure and bonding Three isomers of the parent tetrazole exist, differing in the position of the double bonds: 1''H''-, 2''H''-, and 5''H''-tetrazole. The 1''H''- and 2''H''- isomers are tautomers, with the equilibrium lying on the side of 1''H''-tetrazole in the solid phase. In the gas phase, 2''H''-tetrazole dominates. These isomers can be regarded as aromatic, with 6 π-electrons, while the 5''H''-isomer is nonaromatic. Phosphorus analogs do not have the same electronic nature, with 1''H''-tetraphosphole having a more pyramidal geometry of the phosphorus at position 1. Instead, it is the anionic tetraphospholides that are aromatic. Strongly inductive effect, inductively electron-withd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrazole Synthesis 02
A tetrazole is a synthetic organic heterocyclic compound, consisting of a 5-member ring of four nitrogen atoms and one carbon atom. The name tetrazole also refers to the parent compound - a whitish crystalline powder with the formula CH2N4, of which three isomers exist. Structure and bonding Three isomers of the parent tetrazole exist, differing in the position of the double bonds: 1''H''-, 2''H''-, and 5''H''-tetrazole. The 1''H''- and 2''H''- isomers are tautomers, with the equilibrium lying on the side of 1''H''-tetrazole in the solid phase. In the gas phase, 2''H''-tetrazole dominates. These isomers can be regarded as aromatic, with 6 π-electrons, while the 5''H''-isomer is nonaromatic. Phosphorus analogs do not have the same electronic nature, with 1''H''-tetraphosphole having a more pyramidal geometry of the phosphorus at position 1. Instead, it is the anionic tetraphospholides that are aromatic. Strongly inductively electron-withdrawing functional groups attached to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Losartan
Losartan, sold under the brand name Cozaar among others, is a medication used to treat high blood pressure (hypertension). It is in the angiotensin receptor blocker (ARB) family of medication, and is considered protective of the kidneys. Besides hypertension, it is also used in diabetic kidney disease, heart failure, and left ventricular enlargement. It comes as a tablet that is taken by mouth. It may be used alone or in addition to other blood pressure medication. Up to six weeks may be required for the full effects to occur. Common adverse effects include muscle cramps, stuffy nose, dizziness, cough, high blood potassium, and anemia. Severe adverse effects may include angioedema, low blood pressure, and kidney problems. Use during pregnancy may result in harm to the baby. Use is not recommended during breastfeeding. It works by blocking angiotensin II. Losartan was patented in 1986, and approved for medical use in the United States in 1995. It is on the World Health ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminoguanidine
Pimagedine, also known as aminoguanidine, is an investigational drug for the treatment of diabetic nephropathy that is no longer under development as a drug. Pimagedine functions as an inhibitor of diamine oxidase and nitric oxide synthase. It acts to reduce levels of advanced glycation end products (AGEs) through interacting with 3-deoxyglucosone, glyoxal, methylglyoxal, and related dicarbonyls. These reactive species are converted to less reactive heterocycles by this condensation reaction. History Pimagedine was under development as a drug for kidney diseases by the pharmaceutical company Alteon (now known Synvista Therapeutics Inc.) that was founded in 1986. In 1987, Alteon acquired a license to intellectual property relating to AGE inhibition from Rockefeller University. In 1989, Alteon and Marion Merrell Dow Inc (MMD) entered into a joint development program for pimagedine. In 1992, Alteon licensed a patent from Rockefeller University relating to the use of pimagedine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalosporin
The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus '' Acremonium'', which was previously known as ''Cephalosporium''. Together with cephamycins, they constitute a subgroup of β-lactam antibiotics called cephems. Cephalosporins were discovered in 1945, and first sold in 1964. Discovery The aerobic mold which yielded cephalosporin C was found in the sea near a sewage outfall in Su Siccu, by Cagliari harbour in Sardinia, by the Italian pharmacologist Giuseppe Brotzu in July 1945. Structure Cephalosporin contains a 6-membered dihydrothiazine ring. Substitutions at position 3 generally affect pharmacology; substitutions at position 7 affect antibacterial activity, but these cases are not always true. Medical uses Cephalosporins can be indicated for the prophylaxis and treatment of infections caused by bacteria susceptible to this particular form of antibiotic. First-generation cephalosporins are active predominant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterocyclic Compound
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles. Examples of heterocyclic compounds include all of the nucleic acids, the majority of drugs, most biomass (cellulose and related materials), and many natural and synthetic dyes. More than half of known compounds are heterocycles. 59% of US FDA-approved drugs contain nitrogen heterocycles. Classification The study of organic heterocyclic chemistry focuses especially on organic unsaturated derivatives, and the preponderance of work and applications involves unstrained organic 5- and 6-membered rings. Included are pyridine, thiophene, pyrrole, and furan. Another large class of organic heterocycles refers to those fused to benzene rings. For example, the fused benzene derivatives of py ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. It is a common element in the universe, estimated at Abundance of the chemical elements, seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element chemical bond, bond to form N2, a colourless and odourless diatomic molecule, diatomic gas. N2 forms about 78% of Atmosphere of Earth, Earth's atmosphere, making it the most abundant chemical species in air. Because of the volatility of nitrogen compounds, nitrogen is relatively rare in the solid parts of the Earth. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772 and independently by Carl Wilhelm Scheele and Henry Cavendish at about the same time. The name was suggested by French chemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MTT Assay
The MTT assay is a colorimetric assay for assessing cell metabolic activity. NAD(P)H-dependent cellular oxidoreductase enzymes may, under defined conditions, reflect the number of viable cells present. These enzymes are capable of reducing the tetrazolium dye MTT, which is chemically 3-(4,5- di methyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide, to its insoluble formazan, which has a purple color. Other closely related tetrazolium dyes including XTT, MTS and the WSTs, are used in conjunction with the intermediate electron acceptor, 1-methoxy phenazine methosulfate (PMS). With WST-1, which is cell-impermeable, reduction occurs outside the cell via plasma membrane electron transport. However, this traditionally assumed explanation is currently contended as proof has also been found of MTT reduction to formazan in lipidic cellular structures without apparent involvement of oxidoreductases. Tetrazolium dye assays can also be used to measure cytotoxicity (loss of viable cells) or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tautomer
In chemistry, tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert. The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the relocation of a hydrogen atom within the compound. The phenomenon of tautomerization is called tautomerism, also called desmotropism. Tautomerism is for example relevant to the behavior of amino acids and nucleic acids, two of the fundamental building blocks of life. Care should be taken not to confuse tautomers with depictions of "contributing structures" in chemical resonance. Tautomers are distinct chemical species that can be distinguished by their differing atomic connectivities, molecular geometries, and physicochemical and spectroscopic properties, whereas resonance forms are merely alternative Lewis structure (valence bond theory) depictions of a single chemical species, whose true structure is a quantum superposition, essentially the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloaddition
In organic chemistry, a cycloaddition is a chemical reaction in which "two or more Unsaturated hydrocarbon, unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of the Multiplicity (chemistry)#Molecules, bond multiplicity". The resulting reaction is a cyclization reaction. Many but not all cycloadditions are Concerted reaction, concerted and thus pericyclic. Nonconcerted cycloadditions are not pericyclic. As a class of addition reaction, cycloadditions permit carbon–carbon bond formation without the use of a nucleophile or electrophile. Cycloadditions can be described using two systems of notation. An older but still common notation is based on the size of linear arrangements of atoms in the reactants. It uses parentheses: where the variables are the numbers of linear atoms in each reactant. The product is a cycle of size . In this system, the standard Diels-Alder reaction is a (4 + 2)-cyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diazonium Compound
Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halide. The parent, compound where R is hydrogen, is diazenylium. Structure and general properties Arene derivatives According to X-ray crystallography the linkage is linear in typical diazonium salts. The bond distance in benzenediazonium tetrafluoroborate is 1.083(3) Angstrom, Å, which is almost identical to that for dinitrogen molecule (N≡N). The linear free energy constants σm and σp indicate that the diazonium group is strongly electron-withdrawing. Thus, the diazonio-substituted phenols and benzoic acids have greatly reduced p''K''a values compared to their unsubstituted counterparts. The p''K''a of phenolic proton of 4-hydroxybenzenediazonium is 3.4, versus 9.9 for phenol itself. In other words, the diazonium group raises the ionization constant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
