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Pictet-Gams Isoquinoline Synthesis
Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline and quinoline are benzopyridines, which are composed of a benzene ring fused to a pyridine ring. In a broader sense, the term isoquinoline is used to make reference to isoquinoline derivatives. 1-Benzylisoquinoline is the structural backbone in naturally occurring alkaloids including papaverine. The isoquinoline ring in these natural compound derives from the aromatic amino acid tyrosine. Properties Isoquinoline is a colorless hygroscopic liquid at temperatures above its melting point with a penetrating, unpleasant odor. Impure samples can appear brownish, as is typical for nitrogen heterocycles. It crystallizes in platelets that have a low solubility in water but dissolve well in ethanol, acetone, diethyl ether, carbon disulfide, and other common organic solvents. It is also soluble in dilute acids as the protonated derivative. Being an analog of pyridine, isoquinoline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of Chemistry
The Royal Society of Chemistry (RSC) is a learned society (professional association) in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society, and the Society for Analytical Chemistry with a new Royal Charter and the dual role of learned society and professional body. At its inception, the Society had a combined membership of 34,000 in the UK and a further 8,000 abroad. The headquarters of the Society are at Burlington House, Piccadilly, London. It also has offices in Thomas Graham House in Cambridge (named after Thomas Graham (chemist), Thomas Graham, the first president of the Chemical Society) where ''RSC Publishing'' is based. The Society has offices in the United States, on the campuses of The University of Pennsylvania and Drexel University, at the University City Science Center in Philadelphia, Pennsylvania, in both Beijing a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solubility
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be " miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. M. Diepen (1966): "Gas—Gas Equilibria". ''Journal of Chemical Physics'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lewis Acid
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a dative bond with a Lewis acid to form a Lewis adduct. For example, NH3 is a Lewis base, because it can donate its lone pair of electrons. Trimethylborane (Me3B) is a Lewis acid as it is capable of accepting a lone pair. In a Lewis adduct, the Lewis acid and base share an electron pair furnished by the Lewis base, forming a dative bond. In the context of a specific chemical reaction between NH3 and Me3B, a lone pair from NH3 will form a dative bond with the empty orbital of Me3B to form an adduct NH3•BMe3. The terminology refers to the contributions of Gilbert N. Lewis. From p. 142: "We are inclined to think of substances as po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adduct
An adduct (from the Latin ''adductus'', "drawn toward" alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is considered a distinct molecular species. Examples include the addition of sodium bisulfite to an aldehyde to give a sulfonate. It can just be considered as a single product resulting from the direct combination of different molecules which comprises all the reactant molecules' atoms. Adducts often form between Lewis acids and Lewis bases. A good example is the formation of adducts between the Lewis acid borane and the oxygen atom in the Lewis bases, tetrahydrofuran (THF): BH3·O(CH2)4 or diethyl ether: BH3·O(CH3CH2)2. Many Lewis acids and Lewis bases reacting in the gas phase or in non-aqueous solvents to form adducts have been examined in the ECW model. Trimethylboron, trimethyltin chloride and bis(hexaflu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strong Acid
Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a proton, H+, and an anion, A-. The dissociation of a strong acid in solution is effectively complete, except in its most concentrated solutions. :HA -> H+ + A- Examples of strong acids are hydrochloric acid (HCl), perchloric acid (HClO4), nitric acid (HNO3) and sulfuric acid (H2SO4). A weak acid is only partially dissociated, with both the undissociated acid and its dissociation products being present, in solution, in equilibrium with each other. :HA H+ + A- Acetic acid (CH3COOH) is an example of a weak acid. The strength of a weak acid is quantified by its acid dissociation constant, K_\ce value. The strength of a weak organic acid may depend on substituent effects. The strength of an inorganic acid is dependent on the oxidation state for the atom to which the proton may be attached. Acid strength is solvent-dependent. For example, hydrogen chloride is a strong acid in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salts
In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions. The component ions in a salt compound can be either inorganic, such as chloride (Cl−), or organic, such as acetate (). Each ion can be either monatomic, such as fluoride (F−), or polyatomic, such as sulfate (). Types of salt Salts can be classified in a variety of ways. Salts that produce hydroxide ions when dissolved in water are called ''alkali salts'' and salts that produce hydrogen ions when dissolved in water are called ''acid salts''. ''Neutral salts'' are those salts that are neither acidic nor basic. Zwitterions contain an anionic and a cationic centre in the same molecule, but are not considered salts. Examples of zwitterions are amino acids, many metabolites, peptides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Dissociation Constant
In chemistry, an acid dissociation constant (also known as acidity constant, or acid-ionization constant; denoted ) is a quantitative measure of the strength of an acid in solution. It is the equilibrium constant for a chemical reaction :HA A^- + H^+ known as dissociation in the context of acid–base reactions. The chemical species HA is an acid that dissociates into , the conjugate base of the acid and a hydrogen ion, . The system is said to be in equilibrium when the concentrations of its components will not change over time, because both forward and backward reactions are occurring at the same rate. The dissociation constant is defined by :K_\text = \mathrm, or :\mathrmK_\ce = - \log_ K_\text = \log_\frac where quantities in square brackets represent the concentrations of the species at equilibrium. Theoretical background The acid dissociation constant for an acid is a direct consequence of the underlying thermodynamics of the dissociation reaction; the p''K''a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Base (chemistry)
In chemistry, there are three definitions in common use of the word base, known as Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form Hydroxide ions OH−. These ions can react with hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction An acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH via titration. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their applica .... A base was therefore a metal hydroxide such as Sodium hydroxide, NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by certain characteristic properties. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog (chemistry)
A structural analog (analogue in modern traditional English; Commonwealth English), also known as a chemical analog or simply an analog, is a compound having a structure similar to that of another compound, but differing from it in respect to a certain component. It can differ in one or more atoms, functional groups, or substructures, which are replaced with other atoms, groups, or substructures. A structural analog can be imagined to be formed, at least theoretically, from the other compound. Structural analogs are often isoelectronic. Despite a high chemical similarity, structural analogs are not necessarily functional analogs and can have very different physical, chemical, biochemical, or pharmacological properties. In drug discovery, either a large series of structural analogs of an initial lead compound are created and tested as part of a structure–activity relationship study or a database is screened for structural analogs of a lead compound. Chemical analogues of il ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical synt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent. It has an "ether-like" odor, but commercial samples are typically contaminated with foul-smelling impurities.. It is of comparable toxicity to carbon monoxide. History In 1796, the German chemist Wilhelm August Lampadius (1772–1842) first prepared carbon disulfide by heating pyrite with moist charcoal. He called it "liquid sulfur" (''flüssig Schwefel''). The composition of carbon disulfide was finally determined in 1813 by the team of the Swedish chemist Jöns Jacob Berzelius (1779–1848) and the Swiss-British chemist Alexander Marcet (1770–1822). Their analysis was consistent with an empirical formula of CS2. Occurrence, manufacture, properties Small amounts of carbon disulfide are released by volcanic eruptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
