Hydrazones are a class of organic compounds with the structure R1R2C=N−NH2. They are related to ketones and aldehydes by the replacement of the oxygen =O with the =N−NH2 functional group. They are formed usually by the action of hydrazine on ketones or aldehydes.
Semiheavy water is the result of replacing one of the protium in normal water with deuterium. It exists whenever there is water with light hydrogen (protium, 1H) and deuterium (D or 2H) in the mix. This is because hydrogen atoms (1H and 2H) are rapidly exchanged between water molecules. Water containing 50% 1H and 50% 2H, is about 50% H2HO and 25% each of H2O and 2H2O, in dynamic equilibrium. In normal water, about 1 molecule in 3,200 is HDO (one hydrogen in 6,400 is 2H). By comparison, heavy water D2O occurs at a proportion of about 1 molecule in 41 million (i.e., one in 6,4002). This makes semiheavy water far more common than "normal" heavy water.
Propyne (methylacetylene) is an alkyne with the chemical formula CH3C≡CH. It is a component of MAPD gas—along with its isomer propadiene (allene), which was commonly used in gas welding. Unlike acetylene, propyne can be safely condensed.
In nuclear magnetic resonance (NMR) spectroscopy, the chemical shift is the resonant frequency of an atomic nucleus relative to a standard in a magnetic field. Often the position and number of chemical shifts are diagnostic of the structure of a molecule. Chemical shifts are also used to describe signals in other forms of spectroscopy such as photoemission spectroscopy.
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic field. This re-orientation occurs with absorption of electromagnetic radiation in the radio frequency region from roughly 4 to 900 MHz, which depends on the isotopic nature of the nucleus and increased proportionally to the strength of the external magnetic field. Notably, the resonance frequency of each NMR-active nucleus depends on its chemical environment. As a result, NMR spectra provide information about individual functional groups present in the sample, as well as about connections between nearby nuclei in the same molecule. As the NMR spectra are unique or highly characteristic to individual compounds and functional groups, NMR spectroscopy is one of the most important methods to identify molecular structures, particularly of organic compounds.
Tetramethylsilane (abbreviated as TMS) is the organosilicon compound with the formula Si(CH3)4. It is the simplest tetraorganosilane. Like all silanes, the TMS framework is tetrahedral. TMS is a building block in organometallic chemistry but also finds use in diverse niche applications.
Hydrogen (1H) has three naturally occurring isotopes: 1H, 2H, and 3H. 1H and 2H are stable, while 3H has a half-life of 12.32(2) years. Heavier isotopes also exist; all are synthetic and have a half-life of less than 1 zeptosecond (10−21 s). Of these, 5H is the least stable, while 7H is the most.
A corrosion inhibitor or anti-corrosive is a chemical compound added to a liquid or gas to decrease the corrosion rate of a metal that comes into contact with the fluid. The effectiveness of a corrosion inhibitor depends on fluid composition and dynamics. Corrosion inhibitors are common in industry, and also found in over-the-counter products, typically in spray form in combination with a lubricant and sometimes a penetrating oil. They may be added to water to prevent leaching of lead or copper from pipes.
o-Phenylenediamine (OPD) is an organic compound with the formula C6H4(NH2)2. This aromatic diamine is an important precursor to many heterocyclic compounds. OPD is a white compound although samples appear darker owing to oxidation by air. It is isomeric with m-phenylenediamine and p-phenylenediamine.
Carbon-13 (C13) nuclear magnetic resonance is the application of nuclear magnetic resonance (NMR) spectroscopy to carbon. It is analogous to proton NMR and allows the identification of carbon atoms in an organic molecule just as proton NMR identifies hydrogen atoms. 13C NMR detects only the 13
C
isotope. The main carbon isotope, 12
C
does not produce an NMR signal. Although ca. 1 mln. times less sensitive than 1H NMR spectroscopy, 13C NMR spectroscopy is widely used for characterizing organic and organometallic compounds, primarily because 1H-decoupled 13C-NMR spectra are more simple, have a greater sensitivity to differences in the chemical structure, and, thus, are better suited for identifying molecules in complex mixtures. At the same time, such spectra lack quantitative information about the atomic ratios of different types of carbon nuclei, because nuclear Overhauser effect used in 1H-decoupled 13C-NMR spectroscopy enhances the signals from carbon atoms with a larger number of hydrogen atoms attached to them more than from carbon atoms with a smaller number of H's, and because full relaxation of 13C nuclei is usually not attained, and the nuclei with shorter relaxation times produce more intense signals.
In nuclear chemistry and nuclear physics, J-couplings are mediated through chemical bonds connecting two spins. It is an indirect interaction between two nuclear spins that arises from hyperfine interactions between the nuclei and local electrons. In NMR spectroscopy, J-coupling contains information about relative bond distances and angles. Most importantly, J-coupling provides information on the connectivity of chemical bonds. It is responsible for the often complex splitting of resonance lines in the NMR spectra of fairly simple molecules.
Deuterated DMSO, also known as dimethyl sulfoxide-d6, is an isotopologue of dimethyl sulfoxide (DMSO, (CH3)2S=O)) with chemical formula ((CD3)2S=O) in which the hydrogen atoms ("H") are replaced with their isotope deuterium ("D"). Deuterated DMSO is a common solvent used in NMR spectroscopy.
Benzotriazole (BTA) is a heterocyclic compound with the chemical formula C6H5N3. Its five-membered ring contains three consecutive nitrogen atoms. This bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and triazole. This white-to-light tan solid has a variety of uses, for instance, as a corrosion inhibitor for copper.
Carbon satellites in physics and spectroscopy, are small peaks that can be seen shouldering the main peaks in the nuclear magnetic resonance (NMR) spectrum. These peaks can occur in the NMR spectrum of any NMR active atom where those atoms adjoin a carbon atom. However, Carbon satellites are most often encountered in proton NMR.
1H-Phenalene, often called simply phenalene is a polycyclic aromatic hydrocarbon (PAH). Like many PAHs, it is an atmospheric pollutant formed during the combustion of fossil fuels. It is the parent compound for the phosphorus-containing phosphaphenalenes.
KF-26777 is a drug which acts as a potent and selective antagonist for the adenosine A3 receptor, with sub-nanomolar affinity (A3 Ki=0.2nM) and high selectivity over the other three adenosine receptor subtypes. Simple xanthine derivatives such as caffeine and DPCPX have generally low affinity for the A3 subtype and must be extended by expanding the ring system and adding an aromatic group to give high A3 affinity and selectivity.
In organic chemistry, phosphonium coupling is a cross-coupling reaction for organic synthesis. It is a mild, efficient, chemoselective and versatile methodology for the formation of C–C, C–N, C–O, and C–S bond of unactivated and unprotected tautomerizable heterocycles. The method was originally reported in 2004. The C–OH bond of a tautomerizable heterocycle is activated with a phosphonium salt, and subsequent functionalization with either a nucleophile through SNAr displacement or an organometallic through transition metal catalyzed cross coupling reaction. The in situ activation of the C-OH bond in phosphonium coupling has been applied to cross coupling reactions of tautomerizable heterocycles and arenols using other types of activating reagents.
HBTU is a coupling reagent used in solid phase peptide synthesis. It was introduced in 1978 and shows resistance against racemization. It is used because of its mild activating properties.
THJ-2201 is an indazole-based synthetic cannabinoid that presumably acts as a potent agonist of the CB1 receptor and has been sold online as a designer drug.
AB-CHFUPYCA is a compound that was first identified as a component of synthetic cannabis products in Japan in 2015. The name "AB-CHFUPYCA" is an acronym of its systematic name N-(1-Amino-3-methyl-1-oxoButan-2-yl)-1-(CycloHexylmethyl)-3-(4-FlUorophenyl)-1H-PYrazole-5-CarboxAmide. There are two known regioisomers of AB-CHFUPYCA: 3,5-AB-CHMFUPPYCA (pictured) and 5,3-AB-CHMFUPPYCA. The article[1] refers to both 3,5-AB-CHMFUPPYCA and 5,3-AB-CHMFUPPYCA as AB-CHMFUPPYCA isomers, so AB-CHMFUPPYCA and AB-CHFUPYCA are not names for a unique chemical structure.
