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| Names | |
|---|---|
| Preferred IUPAC name 4,7-Dihydro-2H-isoindole | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
PubChem CID | |
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| Properties | |
| C8H9N | |
| Molar mass | 119.167 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
4,7-Dihydroisoindole in heterocyclic chemistry is a reduced form of isoindole. 4,7-Dihydroisoindole is a useful building block for extended porphyrins which are relevant as materials for optical applications.
An early attempt to access 4,7-dihydroisoindole — the closest relative of thermodynamically unstable isoindole was performed 1985. [1] It was based on the classical Paal-Knorr synthesis under conditions which probably harmed the electron-rich pyrrole ring. Observed instability of 4,7-dihydroisoindole led researchers to conclude that it was not a useful intermediate in the porphyrin chemistry.
It turned out that changing the conditions made it possible to isolate 4,7-dihydroisoindole. Three-step synthesis starting from tosylacetylene which includes Diels-Alder reaction, Barton-Zard synthesis and thermal decarboxylation was reported. [2]
Though it was expected that under acidic or basic conditions the migration of double bond in 4,7-dihydroisoindole would happen, this does not take when either strong bases (potassium tert-butoxide, potassium hydroxide) or acids (trifluoroacetic acid, p-toluenesulfonic acid) are involved. A likely reason for such stability is that the pyrrolic residue is more acidic (as NH-acid) as well as more nucleophilic than the respective reaction centers involved in the anticipated double bond migration; thus, the pyrrolic ring may serve to protect the double bond from the initiation of both carbocationic and carbanionic shifts.
4,7-Dihydroisoindole is universally a synthon of extended porphyrins, since its isolated double bond in the annelated cyclohexene ring can allow for modification by addition or cycloaddition reactions. Addition reactions can furnish new intermediates for benzosubstituted tetrabenzoporphyrins, while the use of cycloaddition reactions can lead to new tetranaphthoporphyrins. [3]
In organic chemistry, a ketene is an organic compound of the form RR'C=C=O, where R and R' are two arbitrary monovalent chemical groups. The name may also refer to the specific compound ethenone H2C=C=O, the simplest ketene.
Pyrrole is a heterocyclic, aromatic, organic compound, a five-membered ring with the formula C4H4NH. It is a colorless volatile liquid that darkens readily upon exposure to air. Substituted derivatives are also called pyrroles, e.g., N-methylpyrrole, C4H4NCH3. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme.
Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans.
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Arynes and benzynes are highly reactive species derived from an aromatic ring by removal of two substituents. Arynes are examples of didehydroarenes, although 1,3- and 1,4-didehydroarenes are also known. Arynes are examples of strained alkynes.
Organoboron chemistry or organoborane chemistry is the chemistry of organoboron compounds or organoboranes, which are chemical compounds of boron and carbon that are organic derivatives of borane (BH3), for example trialkyl boranes..
The Knorr pyrrole synthesis is a widely used chemical reaction that synthesizes substituted pyrroles (3). The method involves the reaction of an α-amino-ketone (1) and a compound containing an electron-withdrawing group α to a carbonyl group (2).
The Barton–McCombie deoxygenation is an organic reaction in which a hydroxy functional group in an organic compound is replaced by a hydrogen to give an alkyl group. It is named after British chemists Sir Derek Harold Richard Barton and Stuart W. McCombie.
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In organic chemistry, the Paal–Knorr Synthesis is a reaction used to synthesize substituted furans, pyrroles, or thiophenes from 1,4-diketones. It is a synthetically valuable method for obtaining substituted furans and pyrroles, which are common structural components of many natural products. It was initially reported independently by German chemists Carl Paal and Ludwig Knorr in 1884 as a method for the preparation of furans, and has been adapted for pyrroles and thiophenes. Although the Paal–Knorr synthesis has seen widespread use, the mechanism wasn't fully understood until it was elucidated by V. Amarnath et al. in the 1990s.
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The Stieglitz rearrangement is a rearrangement reaction in organic chemistry which is named after the American chemist Julius Stieglitz (1867–1937) and was first investigated by him and Paul Nicholas Leech in 1913. It describes the 1,2-rearrangement of trityl amine derivatives to triaryl imines. It is comparable to a Beckmann rearrangement which also involves a substitution at a nitrogen atom through a carbon to nitrogen shift. As an example, triaryl hydroxylamines can undergo a Stieglitz rearrangement by dehydration and the shift of a phenyl group after activation with phosphorus pentachloride to yield the respective triaryl imine, a Schiff base.
Indole is an aromatic, heterocyclic, organic compound with the formula C8H7N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indole is widely distributed in the natural environment and can be produced by a variety of bacteria. As an intercellular signal molecule, indole regulates various aspects of bacterial physiology, including spore formation, plasmid stability, resistance to drugs, biofilm formation, and virulence. The amino acid tryptophan is an indole derivative and the precursor of the neurotransmitter serotonin.
The Barton–Zard reaction is a route to pyrrole derivatives via the reaction of a nitroalkene with an α-isocyanoacetate under basic conditions. It is named after Derek Barton and Samir Zard who first reported it in 1985.
In organic chemistry, enone–alkene cycloadditions are a version of the [2+2] cycloaddition This reaction involves an enone and alkene as substrates. Although the concerted photochemical [2+2] cycloaddition is allowed, the reaction between enones and alkenes is stepwise and involves discrete diradical intermediates.
Decarboxylative cross coupling reactions are chemical reactions in which a carboxylic acid is reacted with an organic halide to form a new carbon-carbon bond, concomitant with loss of CO2. Aryl and alkyl halides participate. Metal catalyst, base, and oxidant are required.
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Carbonyl olefin metathesis is a type of metathesis reaction that entails, formally, the redistribution of fragments of an alkene and a carbonyl by the scission and regeneration of carbon-carbon and carbon-oxygen double bonds respectively. It is a powerful method in organic synthesis using simple carbonyls and olefins and converting them into less accessible products with higher structural complexity.