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Rearrangement Reactions A rearrangement reaction in organic chemistry may simply be defined as a chemical change where the carbon skeleton of an organic compound rearranges itself to give rise to a structural isomer. Generally, a group moves from one atom to another atom within the same molecule.
- 8.2.2 some characteristic Features of π Bonds
- Problem 8.6
- 8.4 ClassifiCation of organiC Compounds
- (a) alicyclic compounds
- (b) aromatic compounds
- Heterocyclic aromatic compounds
- 8.4.1 functional group
- 8.4.2 Homologous series
- 8.5 nomEnClaturE of organiC Compounds
- 8.5.1 the iupaC system of nomenclature
- 8.6 isOmerism
- 8.6.2 Stereoisomerism
- 8.7 FUNDAMENTAL CONCEPTS IN ORGANIC REACTION MECHANISM
- Nucleophiles and Electrophiles
- Problem 8.12
- 8.7.3 Electron Movement in Organic Reactions
- 8.7.4 electron displacement effects in covalent Bonds
- Problem 8.16
- Problem 8.17
- 8.7.7 resonance effect
- (i) Positive Resonance Effect (+R effect)
- 8.7.8 electromeric effect (e effect)
- 8.8 methOds OF PuriFicatiOn OF Organic cOmPOunds
- 8.8.1 sublimation
- 8.8.2 crystallisation
- 8.8.5 chromatography
- 8.9 qualitatiVe analysis OF Organic cOmPOunds
- 8.9.2 detection of Other elements
- (C) Test for Halogens
- 8.10 quantitatiVe analysis
- 1.4 × M × 2(V − V / 2) =
In a π (pi) bond formation, parallel orientation of the two p orbitals on adjacent atoms is necessary for a proper sideways overlap. Thus, in H2C=CH molecule all the atoms 2 must be in the same plane. The p orbitals are mutually parallel and both the p orbitals are perpendicular to the plane of the molecule. Rotation of one CH fragment with respect...
Expand each of the following bond-line formulas to show all the atoms including carbon and hydrogen solution
The existing large number of organic compounds and their ever-increasing numbers has made it necessary to classify them on the basis of their structures. Organic compounds are broadly classified as follows:
Alicyclic (aliphatic cyclic) compounds contain carbon atoms joined in the form of a ring (homocyclic). Cyclopropane Cyclohexene Cyclohexane Sometimes atoms other than carbon are also present in the ring (heterocylic). Tetrahydrofuran given below is an example of this type of compound: Tetrahydrofuran These exhibit some of the properties similar t...
Aromatic compounds are special types of compounds. You will learn about these compounds in detail in Unit 9. These include benzene and other related ring compounds (benzenoid). Like alicyclic compounds, aromatic comounds may also have hetero atom in the ring. Such compounds are called hetrocyclic aromatic compounds. Some of the examples of various ...
Furan Thiophene Pyridine Organic compounds can also be classified on the basis of functional groups, into families or homologous series.
The functional group is an atom or a group of atoms joined to the carbon chain which is responsible for the characteristic chemical properties of the organic compounds. The examples are hydroxyl group (–OH), aldehyde group (–CHO) and carboxylic acid group (– COOH) etc.
A group or a series of organic compounds each containing a characteristic functional group forms a homologous series and the members of the series are called homologues. The members of a homologous series can be represented by general molecular formula and the successive members differ from each other in molecular formula by a –CH 2 unit. There are...
Organic chemistry deals with millions of compounds. In order to clearly identify them, a systematic method of naming has been developed and is known as the iupaC (international union of pure and applied Chemistry) system of nomenclature. In this systematic nomenclature, the names are correlated with the structure such that the reader or listener ca...
A systematic name of an organic compound is generally derived by identifying the parent hydrocarbon and the functional group(s) attached to it. See the example given below. By further using prefixes and suffixes, the parent name can be modified to obtain the actual name. Compounds containing carbon and hydrogen only are called hydrocarbons. A hydro...
The phenomenon of existence of two or more compounds possessing the same molecular formula but different properties is known as isomerism. Such compounds are called as isomers. The following flow chart shows different types of isomerism.
The compounds that have the same constitution and sequence of covalent bonds but differ in relative positions of their atoms or groups in space are called stereoisomers. This special type of isomerism is called as stereoisomerism and can be classified as geometrical and optical isomerism.
In an organic reaction, the organic molecule (also referred as a substrate) reacts with an appropriate attacking reagent and leads to the formation of one or more intermediate(s) and finally product(s) The general reaction is depicted as follows : Attacking Reagent Organic [Intermediate] Product(s) molecule (Substrate) Byproducts Substrate is that ...
Reagents attack the reactive site of the substrate. The reactive site may be electron deficient portion of the molecule (a positive reactive site) e.g., an atom with incomplete electron shell or the positive end of the dipole in the molecule. If the attacking species is electron rich, it attacks these sites. If attacking species is electron deficie...
Giving justification, categorise the following molecules/ions as nucleophile or electrophile:
The movement of electrons in organic reactions can be shown by curved-arrow notation. It shows how changes in bonding occur due to electronic redistribution during the reaction. To show the change in position of a pair of electrons, curved arrow starts from the point from where an electron pair is shifted and it ends at a location to which the pair...
The electron displacement in an organic molecule may take place either in the ground state under the influence of an atom or a substituent group or in the presence of an appropriate attacking reagent. The electron displacements due to the influence of an atom or a substituent group present in the molecule cause permanent polarlisation of the bond. ...
Write resonance structures of CH3COO– and show the movement of electrons by curved arrows. solution First, write the structure and put unshared pairs of valence electrons on appropriate atoms. Then draw the arrows one at a time moving the electrons to get the other structures.
Write resonance structures of CH 2=CH–CHO. Indicate relative stability of the contributing structures. solution Stability: I > II > III [I: Most stable, more number of covalent bonds, each carbon and oxygen atom has an octet and no separation of opposite charge II: negative charge on more electronegative atom and positive charge on more electropo...
The resonance effect is defined as ‘the polarity produced in the molecule by the interaction of two π-bonds or between a π-bond and lone pair of electrons present on an adjacent atom’. The effect is transmitted through the chain. There are two types of resonance or mesomeric effect designated as R or M effect.
In this effect, the transfer of electrons is away from an atom or substituent group attached to the conjugated system. This electron displacement makes certain positions in the molecule of high electron densities. This effect in aniline is shown as :
It is a temporary effect. The organic compounds having a multiple bond (a double or triple bond) show this effect in the presence of an attacking reagent only. It is defined as the complete transfer of a shared pair of π-electrons to one of the atoms joined by a multiple bond on the demand of an attacking reagent. The effect is annulled as soon as ...
Once an organic compound is extracted from a natural source or synthesised in the laboratory, it is essential to purify it. Various methods used for the purification of organic compounds are based on the nature of the compound and the impurity present in it. The common techniques used for purification are as follows : Sublimation Crystallisation Di...
You have learnt earlier that on heating, some solid substances change from solid to vapour state without passing through liquid state. The purification technique based on the above principle is known as sublimation and is used to separate sublimable compounds from non-sublimable impurities.
This is one of the most commonly used techniques for the purification of solid organic compounds. It is based on the difference in the solubilities of the compound and the impurities in a suitable solvent. The impure compound is dissolved in a solvent in which it is sparingly soluble at room temperature but appreciably soluble at higher temperature...
Chromatography is an important technique extensively used to separate mixtures into their components, purify compounds and also to test the purity of compounds. The Fig.8.9 Steam distillation. Steam volatile component volatilizes, the vapours condense in the condenser and the liquid collects in conical flask. name chromatography is based on the G...
m Kjeldahl method is not applicable to compounds containing nitrogen in nitro and azo groups and nitrogen present in the ring (e.g. pyridine) as nitrogen of these compounds does not change to ammonium sulphate under these conditions.
m Kjeldahl method is not applicable to compounds containing nitrogen in nitro and azo groups and nitrogen present in the ring (e.g. pyridine) as nitrogen of these compounds does not change to ammonium sulphate under these conditions.
m Kjeldahl method is not applicable to compounds containing nitrogen in nitro and azo groups and nitrogen present in the ring (e.g. pyridine) as nitrogen of these compounds does not change to ammonium sulphate under these conditions.
m Kjeldahl method is not applicable to compounds containing nitrogen in nitro and azo groups and nitrogen present in the ring (e.g. pyridine) as nitrogen of these compounds does not change to ammonium sulphate under these conditions.
m Kjeldahl method is not applicable to compounds containing nitrogen in nitro and azo groups and nitrogen present in the ring (e.g. pyridine) as nitrogen of these compounds does not change to ammonium sulphate under these conditions.
Benzilic Acid Rearrangement. The benzilic acid rearrangement involves conversion of a 1,2-diketone into a carboxylic acid. The conditions are deceptively simple, hydroxide followed by an acid quench, and lead to the migration of a benzene ring. This mechanism is relatively straightforward.
NH. H. (100%) N. ". . . after ca. 10 seconds, a relatively violent reaction occurred which was accompanied by a dense cloud of white smoke and change in color from the characteristic yellow-green of the starting material to a dark brown."
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Oct 17, 2011 · Introduction to Rearrangement Reactions. Reactions that involve a carbocation intermediate may be accompanied by rearrangements where a pair of electrons from a C-H or C-C bond migrates toward the carbocation, resulting in breakage and formation of a C-H or C-C bond, and formation of a new carbocation. The new carbocation (generally more stable ...
1 RearrangementReactions. 1. Rearrangement ReactionsA rearrangement reaction is a board class of organic reactions in which an atom, ion, group of atoms, or chemical unit migrates from one atom to another atom in the same or different species, resulting in a structural isomer o.
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The term “rearrangement” is used to describe two different types of organic chemical reactions. A rearrangement may involve the one -step migration of an H atom or of a larger molecular fragment within a relatively short lived intermediate. On the other hand, a rearrangement may be a multi-step reaction that includes the migration of an H ...
