In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula R−C(=O)−NR′R″, where R, R', and R″ represent any group, typically organyl groups or hydrogen atoms. The amide group is called a peptide bond when it is part of the main chain of a protein, and an isopeptide bond when it occurs in a side chain, as in asparagine and glutamine. It can be viewed as a derivative of a carboxylic acid with the hydroxyl group replaced by an amine group ; or, equivalently, an acyl (alkanoyl) group joined to an amine group.
In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters between alcohols and nitric acid. The difference between the resulting molecular structures of nitro compounds and nitrates is that the nitrogen atom in nitro compounds is directly bonded to a non-oxygen atom, whereas in nitrate esters, the nitrogen is bonded to an oxygen atom that in turn usually is bonded to a carbon atom.
The Claisen rearrangement is a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation (Δ = −327 kcal/mol.
The Curtius rearrangement, first defined by Theodor Curtius in 1885, is the thermal decomposition of an acyl azide to an isocyanate with loss of nitrogen gas. The isocyanate then undergoes attack by a variety of nucleophiles such as water, alcohols and amines, to yield a primary amine, carbamate or urea derivative respectively. Several reviews have been published.
In stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions. The auxiliary can then be typically recovered for future use.
In organic chemistry, the Arndt–Eistert reaction is the conversion of a carboxylic acid to its homologue. Named for the German chemists Fritz Arndt (1885–1969) and Bernd Eistert (1902–1978), the method entails treating an acid chlorides with diazomethane. It is a popular method of producing β-amino acids from α-amino acids.
The Favorskii rearrangement is principally a rearrangement of cyclopropanones and α-halo ketones that leads to carboxylic acid derivatives. In the case of cyclic α-halo ketones, the Favorskii rearrangement constitutes a ring contraction. This rearrangement takes place in the presence of a base, sometimes hydroxide, to yield a carboxylic acid, but usually either an alkoxide base or an amine to yield an ester or an amide, respectively. α,α'-Dihaloketones eliminate HX under the reaction conditions to give α,β-unsaturated carbonyl compounds.
The Stollé synthesis is a series of chemical reactions that produce oxindoles from anilines and α-haloacid chlorides.
2-Pyridone is an organic compound with the formula C
5H
4NH(O). It is a colourless solid. It is well known to form hydrogen bonded dimers and it is also a classic case of a compound that exists as tautomers.
Prilocaine is a local anesthetic of the amino amide type first prepared by Claes Tegner and Nils Löfgren. In its injectable form, it is often used in dentistry. It is also often combined with lidocaine as a topical preparation for dermal anesthesia, for treatment of conditions like paresthesia. As it has low cardiac toxicity, it is commonly used for intravenous regional anaesthesia (IVRA).
Directed ortho metalation (DoM) is an adaptation of electrophilic aromatic substitution in which electrophiles attach themselves exclusively to the ortho- position of a direct metalation group or DMG through the intermediary of an aryllithium compound. The DMG interacts with lithium through a hetero atom. Examples of DMG's are the methoxy group, a tertiary amine group and an amide group.The compound can be produced by directed lithiation of anisole.
The Wolff rearrangement is a reaction in organic chemistry in which an α-diazocarbonyl compound is converted into a ketene by loss of dinitrogen with accompanying 1,2-rearrangement. The Wolff rearrangement yields a ketene as an intermediate product, which can undergo nucleophilic attack with weakly acidic nucleophiles such as water, alcohols, and amines, to generate carboxylic acid derivatives or undergo [2+2] cycloaddition reactions to form four-membered rings. The mechanism of the Wolff rearrangement has been the subject of debate since its first use. No single mechanism sufficiently describes the reaction, and there are often competing concerted and carbene-mediated pathways; for simplicity, only the textbook, concerted mechanism is shown below. The reaction was discovered by Ludwig Wolff in 1902. The Wolff rearrangement has great synthetic utility due to the accessibility of α-diazocarbonyl compounds, variety of reactions from the ketene intermediate, and stereochemical retention of the migrating group. However, the Wolff rearrangement has limitations due to the highly reactive nature of α-diazocarbonyl compounds, which can undergo a variety of competing reactions.
Diphenylketene is a chemical substance of the ketene family. Diphenylketene, like most stable disubstituted ketenes, is a red-orange oil at room temperature and pressure. Due to the successive double bonds in the ketene structure R1R2C=C=O, diphenyl ketene is a heterocumulene. The most important reaction of diphenyl ketene is the [2+2] cycloaddition at C-C, C-N, C-O, and C-S multiple bonds.
The total synthesis of quinine, a naturally-occurring antimalarial drug, was developed over a 150-year period. The development of synthetic quinine is considered a milestone in organic chemistry although it has never been produced industrially as a substitute for natural occurring quinine. The subject has also been attended with some controversy: Gilbert Stork published the first stereoselective total synthesis of quinine in 2001, meanwhile shedding doubt on the earlier claim by Robert Burns Woodward and William Doering in 1944, claiming that the final steps required to convert their last synthetic intermediate, quinotoxine, into quinine would not have worked had Woodward and Doering attempted to perform the experiment. A 2001 editorial published in Chemical & Engineering News sided with Stork, but the controversy was eventually laid to rest once and for all when Williams and coworkers successfully repeated Woodward's proposed conversion of quinotoxine to quinine in 2007.
The Kulinkovich reaction describes the organic synthesis of substituted cyclopropanols through reaction of esters with dialkyldialkoxytitanium reagents, which are generated in situ from Grignard reagents containing a hydrogen in beta-position and titanium(IV) alkoxides such as titanium isopropoxide. This reaction was first reported by Oleg Kulinkovich and coworkers in 1989.
The Hofmann–Löffler reaction (also referred to as Hofmann–Löffler–Freytag reaction, Löffler–Freytag reaction, Löffler–Hofmann reaction, as well as Löffler's method) is an organic reaction in which a cyclic amine 2 (pyrrolidine or, in some cases, piperidine) is generated by thermal or photochemical decomposition of N-halogenated amine 1 in the presence of a strong acid (concentrated sulfuric acid or concentrated CF3CO2H). The Hofmann–Löffler–Freytag reaction proceeds via an intramolecular hydrogen atom transfer to a nitrogen-centered radical and is an example of a remote intramolecular free radical C–H functionalization.
Strychnine total synthesis in chemistry describes the total synthesis of the complex biomolecule strychnine. The first reported method by the group of Robert Burns Woodward in 1954 is considered a classic in this research field.
An insertion reaction is a chemical reaction where one chemical entity interposes itself into an existing bond of typically a second chemical entity e.g.:
Tetramethoxymethane is a chemical compound which is formally formed by complete methylation of the hypothetical orthocarbonic acid C(OH)4 (orthocarboxylic acid violates the Erlenmeyer rule and is unstable in free state).
Diethyl acetamidomalonate (DEAM) is a derivative of malonic acid diethyl ester. Formally, it is derived through the acetylation of ester from the unstable aminomalonic acid. DEAM serves as a starting material for racemates including both, natural and unnatural α-amino acids or hydroxycarboxylic acids. It is also usable as a precursor in pharmaceutical formulations, particularly in the cases of active ingredients like fingolimod, which is used to treat multiple sclerosis.
