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Chloroformates
Chloroformates are a class of organic compounds with the formula ROC(O)Cl. They are formally esters of chloroformic acid. Most are colorless, volatile liquids that degrade in moist air. A simple example is methyl chloroformate, which is commercially available. Chloroformates are used as reagents in organic chemistry. For example, benzyl chloroformate is used to introduce the Cbz (carboxybenzyl) protecting group and fluorenylmethyloxycarbonyl chloride is used to introduce the FMOC protecting group. Chloroformates are popular in the field of chromatography as derivatization agents. They convert polar compounds into less polar more volatile derivatives. In this way, chloroformates enable relatively simple transformation of large array of metabolites (aminoacids, amines, carboxylic acids, phenols) for analysis by gas chromatography / mass spectrometry. Reactions The reactivity of chloroformates and acyl chlorides are similar. Representative reactions are: * Reaction with amines to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroformate Ester
Chloroformates are a class of organic compounds with the formula ROC(O)Cl. They are formally esters of chloroformic acid. Most are colorless, volatile liquids that degrade in moist air. A simple example is methyl chloroformate, which is commercially available. Chloroformates are used as reagents in organic chemistry. For example, benzyl chloroformate is used to introduce the Cbz (carboxybenzyl) protecting group and fluorenylmethyloxycarbonyl chloride is used to introduce the FMOC protecting group. Chloroformates are popular in the field of chromatography as derivatization agents. They convert polar compounds into less polar more volatile derivatives. In this way, chloroformates enable relatively simple transformation of large array of metabolites (aminoacids, amines, carboxylic acids, phenols) for analysis by gas chromatography / mass spectrometry. Reactions The reactivity of chloroformates and acyl chlorides are similar. Representative reactions are: * Reaction with amines to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroformates
Chloroformates are a class of organic compounds with the formula ROC(O)Cl. They are formally esters of chloroformic acid. Most are colorless, volatile liquids that degrade in moist air. A simple example is methyl chloroformate, which is commercially available. Chloroformates are used as reagents in organic chemistry. For example, benzyl chloroformate is used to introduce the Cbz (carboxybenzyl) protecting group and fluorenylmethyloxycarbonyl chloride is used to introduce the FMOC protecting group. Chloroformates are popular in the field of chromatography as derivatization agents. They convert polar compounds into less polar more volatile derivatives. In this way, chloroformates enable relatively simple transformation of large array of metabolites (aminoacids, amines, carboxylic acids, phenols) for analysis by gas chromatography / mass spectrometry. Reactions The reactivity of chloroformates and acyl chlorides are similar. Representative reactions are: * Reaction with amines to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroformic Acid
Chloroformic acid is an unstable chemical compound with the formula ClCO2H. It is the single acyl-halide derivative of carbonic acid (phosgene is the double acyl-halide derivative). Chloroformic acid is also structurally related to formic acid, which has a hydrogen instead of the chlorine. Despite the similar name, it is very different from chloroform. Chloroformic acid itself is too unstable to be handled for chemical reactions. However, many esters of this carboxylic acid are stable and these chloroformates are important reagents in organic chemistry. They are used to prepare mixed carboxylic acid anhydrides used in peptide synthesis. Like other related halocarbons, it is a potentially dangerous alkylating agent. Important chloroformate esters include 4-nitrophenyl chloroformate, fluorenylmethyloxycarbonylchloride, benzyl chloroformate and ethyl chloroformate. See also * Chloroacetic acids * Dichloroacetic acid * Trichloroacetic acid Trichloroacetic acid (TCA; TCAA; also kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Chloroformate
Methyl chloroformate is the methyl ester of chloroformic acid. It is an oily colorless liquid, although aged samples appear yellow. It is also known for its pungent odor. Preparation Methyl chloroformate can be synthesized using methanol and phosgene. COCl2 + MeOH-> C2H3ClO2 + HCl Properties Methyl chloroformate hydrolyzes in water to form methanol, hydrochloric acid, and carbon dioxide. This decomposition happens violently in the presence of steam, causing foaming. The compound decomposes in heat, which can liberate hydrogen chloride, phosgene, chlorine, or other toxic gases. Uses Methyl chloroformate is used in organic synthesis for the introduction of the methoxycarbonyl functionality to a suitable nucleophile (i.e. carbomethoxylation). Safety Methyl chloroformate, if heated, releases phosgene. It produces hydrogen chloride upon contact with water. It will cause skin damage if in contact with skin. See also *Ethyl chloroacetate *Chloroacetic acid Chloroacetic acid, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benzyl Chloroformate
Benzyl chloroformate, also known as benzyl chlorocarbonate or Z-chloride, is the benzyl ester of chloroformic acid. It can be also described as the chloride of the benzyloxycarbonyl (Cbz or Z) group. In its pure form it is a water-sensitive oily colorless liquid, although impure samples usually appear yellow. It possesses a characteristic pungent odor and degrades in contact with water. The compound was first prepared by Leonidas Zervas in the early 1930s who used it for the introduction of the benzyloxycarbonyl protecting group, which became the basis of the Bergmann-Zervas carboxybenzyl method of peptide synthesis he developed with Max Bergmann. This was the first successful method of controlled peptide chemical synthesis and for twenty years it was the dominant procedure used worldwide until the 1950s. To this day, benzyl chloroformate is often used for amine group protection. Preparation The compound is prepared in the lab by treating benzyl alcohol with phosgene: : PhCH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorenylmethyloxycarbonyl Chloride
Fluorenylmethyloxycarbonyl chloride (Fmoc-Cl) is a chloroformate ester. It is used to introduce the fluorenylmethyloxycarbonyl protecting group as the Fmoc carbamate. Preparation This compound may be prepared by reacting 9-fluorenylmethanol with phosgene Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, espe ...: : References {{reflist Chloroformates Reagents for organic chemistry Reagents for biochemistry Biochemistry methods ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ester
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are fatty acid esters of glycerol; they are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils. Esters typically have a pleasant smell; those of low molecular weight are commonly used as fragrances and are found in essential oils and pheromones. They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties. '' Nomenclature Etymology Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a substance ''consumed'' in the course of a chemical reaction. ''Solvents'', though involved in the reaction mechanism, are usually not called reactants. Similarly, ''catalysts'' are not consumed by the reaction, so they are not reactants. In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates. Definitions Organic chemistry In organic chemistry, the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause the desired transformation of an organic substance. Examples include the Collins reagent, Fenton's reagent, and Grignard reagents. Analytical chemistry In analytical chemistry, a reagent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protecting Group
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group to obtain chemoselectivity in a subsequent chemical reaction. It plays an important role in multistep organic synthesis. In many preparations of delicate organic compounds, some specific parts of their molecules cannot survive the required reagents or chemical environments. Then, these parts, or groups, must be protected. For example, lithium aluminium hydride is a highly reactive but useful reagent capable of reducing esters to alcohols. It will always react with carbonyl groups, and this cannot be discouraged by any means. When a reduction of an ester is required in the presence of a carbonyl, the attack of the hydride on the carbonyl has to be prevented. For example, the carbonyl is converted into an acetal, which does not react with hydrides. The acetal is then called a protecting group for the carbonyl. After the step involving the hydride is complete, the acet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acyl Chloride
In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example of an acyl chloride is acetyl chloride, . Acyl chlorides are the most important subset of acyl halides. Nomenclature Where the acyl chloride moiety takes priority, acyl chlorides are named by taking the name of the parent carboxylic acid, and substituting ''-yl chloride'' for ''-ic acid''. Thus: : : When other functional groups take priority, acyl chlorides are considered prefixes — ''chlorocarbonyl-'': : Properties Lacking the ability to form hydrogen bonds, acyl chlorides have lower boiling and melting points than similar carboxylic acids. For example, acetic acid boils at 118 °C, whereas acetyl chloride boils at 51 °C. Like most carbonyl compounds, infrared spectroscopy reveals a band near 1750 cm−1. The simplest s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines). Important amines include amino acids, biogenic amines, trimethylamine, and aniline; Inorganic derivatives of ammonia are also called amines, such as monochloramine (). The substituent is called an amino group. Compounds with a nitrogen atom attached to a carbonyl group, thus having the structure , are called amides and have different chemical properties from amines. Classification of amines Amines can be classified according to the nature and number of substituents on nitrogen. Aliphatic amines contain only H and alkyl substituents. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
