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Tosyl Hydrazone
Hydrazones are a class of organic compounds with the structure . They are related to ketones and aldehydes by the replacement of the oxygen =O with the = functional group. They are formed usually by the action of hydrazine on ketones or aldehydes. Synthesis Hydrazine, organohydrazines, and 1,1-diorganohydrazines react with aldehydes and ketones to give hydrazones. : Phenylhydrazine reacts with reducing sugars to form hydrazones known as osazones, which was developed by German chemist Emil Fischer as a test to differentiate monosaccharides. Uses Hydrazones are the basis for various analyses of ketones and aldehydes. For example, dinitrophenylhydrazine coated onto a silica sorbent is the basis of an adsorption cartridge. The hydrazones are then eluted and analyzed by HPLC using a UV detector. The compound carbonyl cyanide-''p''-trifluoromethoxyphenylhydrazone (abbreviated as FCCP) is used to uncouple ATP synthesis and reduction of oxygen in oxidative phosphorylation in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer. When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. The human body recycles its own body weight equivalent in ATP each day. It is also a precursor to DNA and RNA, and is used as a coenzyme. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of an adenine attached by the 9-nitrogen atom to the 1′ carbon atom of a sugar (ribose), which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japp–Klingemann Reaction
The Japp–Klingemann reaction is a chemical reaction used to synthesize hydrazones from β-keto-acids (or β-keto-esters) and aryl diazonium salts. The reaction is named after the chemists Francis Robert Japp and Felix Klingemann. : The hydrazone products of the Japp–Klingemann reaction are most often used as intermediates in syntheses of more complex organic molecules. For example, a phenylhydrazone product can be heated in the presence of strong acid to produce an indole via the Fischer indole synthesis. : If there is a leaving group elsewhere in the Japp–Klingemann product, the hydrazone instead can cyclize at that site via a substitution reaction to give a pyrazole. This process is a key part of the synthesis of and related compounds: Reaction mechanism To illustrate the mechanism, the Japp-Klingemann ester variation will be considered. The first step is the deprotonation of the β-keto-ester. The nucleophilic addition of the enolate anion 2 to the diazonium salt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Group
In organic chemistry, a vinyl group (abbr. Vi; IUPAC name: ethenyl group) is a functional group with the formula . It is the ethylene (IUPAC name: ethene) molecule () with one fewer hydrogen atom. The name is also used for any compound containing that group, namely where R is any other group of atoms. An industrially important example is vinyl chloride, precursor to PVC, a plastic commonly known as ''vinyl''. Vinyl is one of the alkenyl functional groups. On a carbon skeleton, sp2-hybridized carbons or positions are often called vinylic. Allyls, acrylates and styrenics contain vinyl groups. (A styrenic crosslinker with two vinyl groups is called '' divinyl benzene''.) Vinyl polymers Vinyl groups can polymerize with the aid of a radical initiator or a catalyst, forming vinyl polymers. Vinyl polymers contain no vinyl groups. Instead they are saturated. The following table gives some examples of vinyl polymers. Reactivity Vinyl derivatives are alkenes. If activated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shapiro Reaction
The Shapiro reaction or tosylhydrazone decomposition is an organic reaction in which a ketone or aldehyde is converted to an alkene through an intermediate hydrazone in the presence of 2 equivalents of organolithium reagent. The reaction was discovered by Robert H. Shapiro in 1967. The Shapiro reaction was used in the Nicolaou Taxol total synthesis. This reaction is very similar to the Bamford–Stevens reaction, which also involves the basic decomposition of tosyl hydrazones. Reaction mechanism In a prelude to the actual Shapiro reaction, a ketone or an aldehyde (1) is reacted with p-toluenesulfonylhydrazide, ''p''-toluenesulfonylhydrazide(2) to form a ''p''-toluenesulfonylhydrazone (or tosylhydrazone) which is a hydrazone (3). Two equivalents of strong base (chemistry), base such as N-Butyllithium, ''n''-butyllithium abstract the Hydron (chemistry), proton from the hydrazone (4) followed by the less carbon acid, acidic proton α to the hydrazone carbon (5), forming a carbanion. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrazone Iodination
Hydrazone iodination is an organic reaction in which a hydrazone is converted into a vinyl iodide by reaction of iodine and a non-nucleophilic base such as DBU. First published by Derek Barton in 1962 the reaction is sometimes referred to as the Barton reaction (although there are many different Barton reactions) or, more descriptively, as the Barton vinyl iodine procedure. The reaction has earlier roots with the 1911 discovery by Wieland and Roseeu that the reaction of hydrazones with iodine alone (without base) results in the azine dimer (structure 2 in ''scheme 1''). In the original Barton publication the reaction was optimized by using a strong guanidine base, the inverse addition of the hydrazone to an iodine solution, and by exclusion of water. When iodine as an electrophile is replaced by aromatic selenyl bromides, the corresponding vinyl selenides are obtained: Reaction mechanism The reaction mechanism proposed in the original Barton publication is outlined as follow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolff–Kishner Reduction
The Wolff–Kishner reduction is a reaction used in organic chemistry to convert carbonyl functionalities into methylene groups. In the context of complex molecule synthesis, it is most frequently employed to remove a carbonyl group after it has served its synthetic purpose of activating an intermediate in a preceding step. As such, there is no obvious retron for this reaction. The reaction was reported by Nikolai Kischner in 1911 and Ludwig Wolff in 1912, In general, the reaction mechanism first involves the ''in situ'' generation of a hydrazone by condensation of hydrazine with the ketone or aldehyde substrate. Sometimes it is however advantageous to use a pre-formed hydrazone as substrate (see modifications). The rate determining step of the reaction is de-protonation of the hydrazone by an alkoxide base to form a diimide anion by a concerted, solvent mediated protonation/de-protonation step. Collapse of this alkyldiimide with loss of N2 leads to formation of an alkylanion whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Azine
Azines are a functional class of organic compounds with the connectivity RR'C=N-N=CRR'. These compounds are the product of the condensation of hydrazine with ketones and aldehydes, although in practice they are often made by alternative routes. Ketazines are azines derived from ketones. For example, acetone azine is the simplest ketazine. Aldazines are azines derived from aldehydes. Preparation The usual method of industrial production is the peroxide process, starting from the ketone, ammonia, and hydrogen peroxide. : In the laboratory, azines are typically prepared by condensation of hydrazine with two equivalents of a carbonyl. Azines are also produced when chalcone reacts with a hydrazone to produce 3,5-diphenyl-1''H''-pyrazole, in a conversion also carried out with hydrazine hydrate. : Reactions Azines characteristically undergo hydrolysis to hydrazines. The reaction proceeds by the intermediacy of a hydrazone: :R2C=N-N=CR2 + H2O → R2C=N-NH2 + R2C=O :R2C=N-NH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oximes
In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted oximes form a closely related family of compounds. Amidoximes are oximes of amides () with general structure . Oximes are usually generated by the reaction of hydroxylamine with aldehydes () or ketones (). The term ''oxime'' dates back to the 19th century, a combination of the words ''oxygen'' and ''imine''. Structure and properties If the two side-chains on the central carbon are different from each other—either an aldoxime, or a ketoxime with two different "R" groups—the oxime can often have two different geometric stereoisomeric forms according to the ''E''/''Z'' configuration. An older terminology of ''syn'' and ''anti'' was used to identify especially aldoximes according to whether the R group was closer or further from the hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibody-drug Conjugate
Antibody-drug conjugates or ADCs are a class of biopharmaceutical drugs designed as a targeted therapy for treating cancer. Unlike chemotherapy, ADCs are intended to target and kill tumor cells while sparing healthy cells. As of 2019, some 56 pharmaceutical companies were developing ADCs. ADCs are complex molecules composed of an antibody linked to a biologically active cytotoxic (anticancer) payload or drug. Antibody-drug conjugates are an example of bioconjugates and immunoconjugates. ADCs combine the targeting properties of Monoclonal antibody, monoclonal antibodies with the cancer-killing capabilities of cytotoxic drugs, designed to discriminate between healthy and diseased tissue. Mechanism of action An anticancer drug is coupled to an antibody that targets a specific tumor antigen (or protein) that, ideally, is only found in or on tumor cells. Antibodies attach themselves to the antigens on the surface of cancerous cells. The biochemical reaction that occurs upon attaching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Biology
Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physical structure of biological macromolecules is known as molecular biology. Molecular biology was first described as an approach focused on the underpinnings of biological phenomena - uncovering the structures of biological molecules as well as their interactions, and how these interactions explain observations of classical biology. In 1945 the term molecular biology was used by physicist William Astbury. In 1953 Francis Crick, James Watson, Rosalind Franklin, and colleagues, working at Medical Research Council unit, Cavendish laboratory, Cambridge (now the MRC Laboratory of Molecular Biology), made a double helix model of DNA which changed the entire research scenario. They proposed the DNA structure based on previous research done by Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
