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In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl (C=O) functional group by formaldehyde (H−CHO) and a primary or secondary amine (−NH2) or ammonia (NH3). [ 1 ] The final product is a β-amino-carbonyl compound also known as a Mannich base.
The nitro-Mannich reaction (or aza-Henry reaction) is the nucleophilic addition of a nitroalkane (or the corresponding nitronate anion) to an imine, resulting in the formation of a beta-nitroamine. [1] With the reaction involving the addition of an acidic carbon nucleophile to a carbon-heteroatom double bond, the nitro-Mannich reaction is ...
A Mannich base is a beta-amino-ketone, which is formed in the reaction of an amine, formaldehyde (or an aldehyde) and a carbon acid. [1] The Mannich base is an endproduct in the Mannich reaction, which is nucleophilic addition reaction of a non-enolizable aldehyde and any primary or secondary amine to produce resonance stabilized imine (iminium ion or imine salt).
Carl Ulrich Franz Mannich (8 March 1877 in Breslau – 5 March 1947 in Karlsruhe) was a German chemist. From 1927 to 1943 he was professor for pharmaceutical chemistry at the University of Berlin. His areas of expertise were keto bases, alcohol bases, derivatives of piperidine, papaverine, lactones and also Digitalis - glycosides.
The ketimine Mannich reaction is an asymmetric synthetic technique using differences in starting material to push a Mannich reaction to create an enantiomeric product with steric and electronic effects, through the creation of a ketimine group. Typically, this is done with a reaction with proline or another nitrogen -containing heterocycle ...
Borylation occurs selectively at the least sterically hindered and least electron rich primary C–H bond in a range of acetals, ethers, amines, and alkyl fluorides. [10] Additionally, no reaction is shown to occur in the absence of primary C–H bonds, for example when cyclohexane is the substrate.
Bonding and structure. [edit] Molecular orbitals of an enolate, showing the occupancy corresponding to the anion. Enolate anions are electronically related to allyl anions. The anionic charge is delocalized over the oxygen and the two carbon sites. Thus they have the character of both an alkoxide and a carbanion.
The stereoselectivity of this reaction was further investigated through study of prochiral methylene hydrogen discrimination. [6] This is due to the extra chiral center at C-2. [7] This process occurs through an oxidation, which regenerates the pyrrolinium cation and formation of an enolate anion, and an intramolecular Mannich reaction.