The study of purified intermediate products of the Bucherer reaction has shown that this reaction proceeds, not via bisuljite addition compounds of the keto form. The Bucherer reaction in organic chemistry is the reversible conversion of a naphthol to a naphthylamine in the presence of ammonia and. Name Reactions pp | Cite as. Bucherer reaction Organic Chemistry Detailed Mechanism Related Reaction Reaction Transformation.
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The Bucherer reaction in organic chemistry is the reversible conversion of a naphthol to a naphthylamine in the presence of ammonia and sodium bisulfite. The Reactioj chemist Robert Lepetit was the first to discover the reaction in The German chemist Hans Theodor Bucherer — discovered independent from Lepetit its reversibility and its potential especially in industrial chemistry. Bucherer published his results in and his name is connected to this reaction.
The organic reaction also goes by the name Bucherer-Lepetit reaction or wrongly the Bucherer-Le Petit reaction. The reaction is used to convert 1,7-dihydroxynaphthalene into 7-aminonaphthol and 1-aminonaphthalenesulfonic acid into 1-hydroxynaphthalenesulfonic acid.
It is also useful for transamination reactions of 2-aminonaphthalenes. This leads to resonance stabilized adducts 1a – 1e. In the next step a bisulfite anion adds to C3 through 1e. This results in the formation of 3a which tautomerizes to the more stable 3b to the sulfonic acid of tetralone. A nucleophilic addition follows of the amine with formation of 4a and its tautomer 4b loses water to form the resonance stabilized cation 5a. This compound is deprotonated to bucehrer imine 5b or the enamine 5c but an equilibrium exists between both species.
The enamine eliminates sodium bisulfite with formation of naphthylamine 6. It is important to stress that this is a reversible reaction. The reaction is summarized as follows:. The Bucherer carbazole synthesis is a buchsrer reaction.
The Bucherer—Bergs reaction is the chemical reaction of carbonyl compounds aldehydes or ketones or cyanohydrins with ammonium carbonate and potassium cyanide to give hydantoins. Overall Reaction Reaction Mechanism Reaction mechanism for bucherrer Bucherer—Bergs reaction Following condensation of the carbonyl with the ammonium, the formed imine is attacked by the isocyanide to form the aminonitrile.
Nucleophilic addition of aminonitrile to CO leads to cyano-carbamic acid, which undergoes an intramolecular ring closing to 5-imino-oxazolidinone.
The 5-imino-oxazolidinone rearranges to form the hydantoin product via an isocyanate intermediate. History Reactions similar to the Bucherer—Bergs eeaction were first seen in bycherer by Ciamician and Silber, reachion obtained 5,5-dimethylhydantoin from a mixture of acetone and hydrocyanic acid after it had been exposed to sunlight for buchherer to seven months. InBergs issued a patent that descr The Bucherer carbazole synthesis is a chemical reaction used to synthesize carbazoles from naphthols and aryl hydrazines using sodium bisulfite.
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The reaction is named after Hans Theodor Bucherer. Hans Theodor Bucherer 19 May — 29 May was a German chemist and gave name to several chemical reactions, for example the Bucherer carbazole synthesis, the Bucherer reaction, and the Bucherer—Bergs reaction Life Bucherer started studying chemistry at the University of Munich, University of Karlsruhe and later with Johannes Wislicenus at the University of Leipzig.
After he received his Ph. D in he worked at BASF. He became professor at Technical University of Dresden in changed to the Technical University of Berlin in and became professor at the Technical University of Munich in Well-known reactions and reagents in organic chemistry include 1,3-Dipolar cycloaddition 2,3-Wittig rearrangement A Abramovitch—Shapiro tryptamine synthesis Acetalisation Acetoacetic ester condensation Achmatowicz reaction Acylation Acyloin condensation Adams catalyst Adams decarboxylation Adkins catalyst Adkins—Peterson reaction Akabori amino acid reaction Alcohol oxidation Alder ene reaction Alder—Stein rules Aldol addition Aldol condensation Algar—Flynn—Oyamada reaction Alkylimino-de-oxo-bisubstitution Alkyne trimerisation Alkyne zipper reaction Allan—Robinson reaction Allylic rearrangement Amadori rearrangement Amine alkylation Angeli—Rimini reaction Andrussov oxidation Appel reaction Arbuzov reaction, Arbusow reaction Arens—van Dorp synthesis, Isler modification Aromatic nitration Arndt—Eistert synthesis Auwers synthesis Azo coupling B Baeyer—Drewson indigo synthesis Baeyer—Villiger oxidation Baeyer—Villiger rearrangement Bakeland process Bakelite In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group —OH bonded directly to an aromatic hydrocarbon group.
The simplest of the class is phenol, CHOH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule. Phenol — the simplest of the phenols. Chemical structure of salicylic acid, the active metabolite of aspirin. Phenols are synthesized industrially as well as naturally. They have higher acidities. The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids their pK is usually between 10 and Sodium bisulfite or sodium bisulphite, sodium hydrogen sulfite is a chemical compound with the chemical formula NaHSO.
Sodium bisulfite is a food additive with E number E This salt of bisulfite can be prepared by bubbling sulfur dioxide in a solution of sodium carbonate in water.
Sodium bisulfite in contact with chlorine bleach aqueous solution of sodium hypochlorite will generate heat and form sodium bisulfate and sodium chloride. Synthesis Sodium bisulfite can be prepared by bubbling excess sulfur dioxide through a solution of suitable base, such as sodium hydroxide or sodium bicarbonate. Carbazole is an aromatic heterocyclic organic compound.
It has a tricyclic structure, consisting of two six-membered benzene rings fused on either side of a bcherer nitrogen-containing ring. The compound’s structure is based on the budherer structure, but in which a second benzene ring is fused onto the five-membered ring at the 2—3 position of indole equivalent to the 9a—4a double bond in carbazole, respectively.
Carbazole is a constituent of tobacco smoke. The second step is a hydrochloric acid-catalyzed rearrangement reaction and ring-closing reaction to tetrahydrocarbazole. In one modification, both steps are rolled into one by carrying out the reaction in acetic acid. In chemistry, a bcuherer reaction or MCRsometimes referred to as a “Multi-component Assembly Process” or MCAPis a chemical reaction where three or more compounds react to form a single product.
History and Types Multicomponent Reactions Multicomponent reactions have been known for over years.
Isocyanide based MCRs are most frequently exploited because the isocyanide is an extraordinary functional group. It is believed to exhibit reso It is a colorless solid, but samples take on a reddish color in air because of oxidation.
It was formerly used to make azo dyes, but it is a known carcinogen and has largely been replaced by less toxic compounds. Reactions It gives no color with iron III chloride.
When reduced by sodium in boiling amyl alcohol solution, it forms tetrahydronaphthylamine, which exhibits the properties of the aliphatic amines in that it is strongly alkaline in reaction, has an ammoniacal odor and cannot be diazotized.
Numerous sulfonic acid derivatives of 2-naphthylamine are reactoon in commerce, such as precursors to dyes.
A ring forming reaction or ring-closing reaction in organic chemistry is a general term for a variety of reactions that introduce one or more rings into a molecule. A heterocycle forming reaction is such a reaction that introduces a new heterocycle.
Named Ring Forming Reactions Named ring forming reactions include not exhaustive: Handbook of Heterocyclic Chemistry 2nd ed. These compounds are colorless solids. They are useful precursors to dyes. With NaOH, converts to 5-aminonaphthol “purpurol”. Acid Black 36 1-Aminonaphthalenesulfonic acid The Strecker amino acid synthesis, also known simply as the Strecker synthesis, was discovered by German chemist Adolph Strecker, and is a term used for a series of chemical reactions that synthesize an amino acid from an aldehyde or ketone.
While usage of ammonium salts gives unsubstituted amino acids, primary and secondary amines also successfully give substituted amino acids. It is one of several aminonaphthalenesulfonic acids, which are derivatives of naphthalene containing both amine and sulfonic acid functional groups. It is a white solid, although commercial samples can appear otherwise. Acid Yellow 19 and C. It is prepared via the Bucherer reaction of 2-hydroxynaphthalenesulfonic acid with ammonia and ammonium sulfite.
The Urech hydantoin synthesis is the chemical reaction of amino acids with potassium cyanate and hydrochloric acid to give hydantoins. Review External links  English translation of German article ‘on lactyl amino acids and lactyl ureas’ by Friedrich Urech See also Bucherer—Bergs reaction It is a colorless solid that arises from the reaction of glycolic acid and urea.
It is an oxidized derivative of imidazolidine. In a more general sense, hydantoins can refer to a groups and a class of compounds with the same ring structure as the parent. For example, phenytoin mentioned below has two phenyl groups substituted onto the number 5 carbon in a hydantoin molecule. He obtained it by hydrogenation of allantoin, hence the name. Friedrich Urech synthesized 5-methylhydantoin in from alanine sulfate and potassium cyanate in what is now known as the Urech hydantoin synthesis The method is very similar to the modern route using alkyl and arylcyanates.
The 5,5-dimethyl compound can also be obtained from acetone cyanohydrin also discovered by Urech: This is a list of scientific phenomena and concepts named after people eponymous phenomena.
For other lists of eponyms, see eponym. Darling Andreev reflection — Alexander F.
Electromagnetic mass was initially a concept of classical mechanics, denoting as to how much the electromagnetic field, or the self-energy, is contributing to the mass of charged particles. It was first derived resction J. Thomson in and was for some time also considered as a dynamical explanation of inertial mass per se.
Reacttion, the relation of mass, momentum, velocity and all forms of energy, including electromagnetic energy, is analyzed reaciton the basis of Albert Einstein’s special relativity and mass—energy equivalence. As to the cause of mass of elementary particles, the Higgs mechanism in the framework of the relativistic Standard Model is currently used.
In addition, some problems concerning the electromagnetic mass and self-energy of charged particles are still studied. Charged particles Rest mass and energy It was recognized by J.
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Thomson in  that a charged sphere moving in a space filled with a medium of a specific inductive capacity the electromagnetic aether of James Clerk Maxwellis h The Borsche—Drechsel cyclization is a chemical reaction used to synthesize tetrahydrocarbazoles by the acid-catalyzed cyclization of cyclohexanone arylhydrazones. The reaction was first described by Edmund Drechsel in  and by Walter Borsche in Its spectrum of activity is similar to that of ampicillin, although it is less susceptible to beta-lactamases than ampicillin and has much higher bioavailability.
Criticism of the theory of relativity of Albert Einstein was mainly expressed in the early years after its publication in the early twentieth century, on scientific, pseudoscientific, philosophical, or ideological bases.
According to some authors, antisemitic objections to Einstein’s Jewish heritage also occasionally played a role in these objections.
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The history of special relativity consists of many theoretical results and empirical findings obtained by Albert A. It culminated in the theory of special relativity proposed by Albert Einstein and subsequent work of Max Planck, Hermann Minkowski and others. Introduction Although Isaac Newton based his physics on absolute time and space, he also adhered to the principle of relativity of Galileo Galilei restating it precisely for mechanical systems .