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Imines
In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions. Structure For ketimines and aldimines, respectively, the five core atoms (C2C=NX and C(H)C=NX, X = H or C) are coplanar. Planarity results from the sp2-hybridization of the mutually double-bonded carbon and the nitrogen atoms. The C=N distance is 1.29-1.31 Å for nonconjugated imines and 1.35 Å for conjugated imines. By contrast, C-N distances in amines and nitriles are 1.47 and 1.16 Å, respectively. Rotation about the C=N bond is slow. Using NMR spectroscopy, both E- and Z-isomers of aldimines have been detected. Owing to steric effects, the E isomer is favored. Nomenclature and classification The term "imine" was coined ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imine General Structure B
In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions. Structure For ketimines and aldimines, respectively, the five core atoms (C2C=NX and C(H)C=NX, X = H or C) are coplanar. Planarity results from the sp2-hybridization of the mutually double-bonded carbon and the nitrogen atoms. The C=N distance is 1.29-1.31 Å for nonconjugated imines and 1.35 Å for conjugated imines. By contrast, C-N distances in amines and nitriles are 1.47 and 1.16 Å, respectively. Rotation about the C=N bond is slow. Using NMR spectroscopy, both E- and Z-isomers of aldimines have been detected. Owing to steric effects, the E isomer is favored. Nomenclature and classification The term "imine" was coin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schiff Base
In organic chemistry, a Schiff base (named after Hugo Schiff) is a compound with the general structure ( = alkyl or aryl, but not hydrogen). They can be considered a sub-class of imines, being either secondary ketimines or secondary aldimines depending on their structure. The term is often synonymous with azomethine which refers specifically to secondary aldimines (i.e. where R' ≠ H). A number of special naming systems exist for these compounds. For instance a Schiff base derived from an aniline, where is a phenyl or a substituted phenyl, can be called an ''anil'', while bis-compounds are often referred to as salen-type compounds. The term Schiff base is normally applied to these compounds when they are being used as ligands to form coordination complexes with metal ions. Such complexes occur naturally, for instance in corrin, but the majority of Schiff bases are artificial and are used to form many important catalysts, such as Jacobsen's catalyst. Synthesis Schiff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophilic Addition
In organic chemistry, a nucleophilic addition reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile, such that the double or triple bond is broken. Nucleophilic additions differ from electrophilic additions in that the former reactions involve the group to which atoms are added accepting electron pairs, whereas the latter reactions involve the group donating electron pairs. Addition to carbon–heteroatom double bonds Nucleophilic addition reactions of nucleophiles with electrophilic double or triple bond (π bonds) create a new carbon center with two additional single, or σ, bonds.March Jerry; (1985). Advanced Organic Chemistry reactions, mechanisms and structure (3rd ed.). New York: John Wiley & Sons, inc. Addition of a nucleophile to carbon–heteroatom double or triple bonds such as >C=O or -C≡N show great variety. These types of bonds are polar (have a large difference in electronegativity bet ... [...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 Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ... 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 compound, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrile
In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons. Inorganic compounds containing the group are not called nitriles, but cyanides instead. Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic. Structure and basic properties The N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond. Nitr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde
In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group. Aldehydes are common and play important roles in the technology and biological spheres. Structure and bonding Aldehydes feature a carbon center that is connected by a double bond to oxygen and a single bond to hydrogen and single bond to a third substituent, which is carbon or, in the case of formaldehyde, hydrogen. The central carbon is often described as being sp2- hybridized. The aldehyde group is somewhat polar. The C=O bond length is about 120-122 picometers. Physical properties and characterization Aldehydes have properties that are diverse and that depend on the remainder of the molecule. Smaller aldehydes are more soluble in water, formaldehyde and acetaldehyde completely so. The volatile aldehydes have pungent odors. Al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetamide
Acetamide (systematic name: ethanamide) is an organic compound with the formula CH3CONH2. It is the simplest amide derived from acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound ''N'',''N''-dimethylacetamide (DMA) is more widely used, but it is not prepared from acetamide. Acetamide can be considered an intermediate between acetone, which has two methyl (CH3) groups either side of the carbonyl (CO), and urea which has two amide (NH2) groups in those locations. Acetamide is also a naturally occurring mineral with the IMA symbol: Ace. Production Laboratory scale Acetamide can be produced in the laboratory from ammonium acetate by dehydration: : H4CH3CO2] → CH3C(O)NH2 + H2O Alternatively acetamide can be obtained in excellent yield via ammonolysis of acetylacetone under conditions commonly used in reductive amination. It can also be made from anhydrous acetic acid, acetonitrile and very well dried hydrogen chloride gas, usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemiaminal
In organic chemistry, a hemiaminal (also carbinolamine) is a functional group or type of chemical compound that has a hydroxyl group and an amine attached to the same carbon atom: . R can be hydrogen or an alkyl group. Hemiaminals are intermediates in imine formation from an amine and a carbonyl by alkylimino-de-oxo-bisubstitution. Hemiaminals can be viewed as a blend of aminals and geminal diol. They are a special case of amino alcohols. Classification according to amine precursor Addition of ammonia The adducts formed by the addition of ammonia to aldehydes have long been studied. Compounds containing both a primary amino group and a hydroxyl group bonded to the same carbon atom are rare. They are invoked but rarely observed as intermediates in the reaction of ammonia and aldehydes and ketones. One example of this rare functionality is the adduct of ammonia and hexafluoroacetone, . The C-substituted derivatives are obtained by reaction of aldehydes and ammonia: :3 RCHO + ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aziridine
Aziridine is an organic compound consisting of the three-membered heterocycle . It is a colorless, toxic, volatile liquid that is of significant practical interest. Aziridine was discovered in 1888 by the chemist Siegmund Gabriel. Its derivatives, also referred to as aziridines, are of broader interest in medicinal chemistry. Structure The bond angles in aziridine are approximately 60°, considerably less than the normal hydrocarbon bond angle of 109.5°, which results in angle strain as in the comparable cyclopropane and ethylene oxide molecules. A banana bond model explains bonding in such compounds. Aziridine is less basic than acyclic aliphatic amines, with a pKa of 7.9 for the conjugate acid, due to increased s character of the nitrogen free electron pair. Angle strain in aziridine also increases the barrier to nitrogen inversion. This barrier height permits the isolation of separate ''invertomers'', for example the ''cis'' and ''trans'' invertomers of ''N''-chlo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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