Types of organic reactions

All the organic reactions can be classified into the following eight types: Substitution reactions Addition reactions Elimination reaction Rearrangement reactions Condensation reaction Isomerisation reaction Pericyclic reactions Polymerization reactions Substitution reaction A substitution reaction is that which involves the direct replacement of an atom or a group of atoms in an organic molecule by another atom…

Free Radicals

A free radical may be defined as an atom or a group having an odd or unpaired electron.These are generally produced by homolytic cleavage of a covalent bond. Classification Free radicals are also classified as primary (1°) , secondary (2°) and tertiary (3°) according as the carbon carrying the unpaired electron is primary, secondary and…

Carbanions

Chemical species bearing a negative charge on carbon and possessing eight electrons in its valence shell are called carbanions. These are produced by heterolytic cleavage of covalent bonds in which the shared pair of electrons remains with the carbon atom. Classification of carbanion Carbanions are also classified as primary (1°), secondary (2°) and tertiary (3°)…

Carbocations

Most of the organic reactions occur through the involvement of certain chemical species.These are generally short lived and highly reactive and hence cannot be isolated.These short lived highly reactive chemical species through which the majority of the organic reactions occur are called reactive intermediates. Ex: Carbocation, carboanion, free radical, carbenes and nitrenes. Carbocation Chemical species…

Hyperconjugation Effect

The inductive effect of the alkyl group on a saturated carbon chain follows the order: (CH3)3C > (CH3)2CH- > CH3CH2-> CH3– When an alkyl group is attached to an unsaturated system such as double bond or a benzene ring, the order of inductive effect is actually reversed.This effect is called hyperconjugation effect or Baker-Nathan effect….

Resonance or mesomerism

The phenomenon of resonance is said to occur whenever for a molecule we can write two or more Lewis structure which differ in the position of electrons but not in the relative position of atoms. The various Lewis structure, none of which is capable of describing all the known properties of the compound are called…

Inductive and Electromeric Effect

Fission of a covalent bond Homolytic fission If a covalent bonds breaks in such a way that each atom takes away one electron of the shared pair, it is called homolytic or symmetrical fission. Homolytic fission is usually indicated by a fish arrow which denotes a one electron displacement. For Ex:  The neutral chemical species…

Electrophiles and Nucleophiles

In an organic reaction, the organic compound called the substrate reacts with a suitable attacking species called the reagent to form products. The formation of products may occur either directly from the reactants through a transition state or through the formation of one or more intermediates. Sometimes by products are also formed from intermediates. Organic…

Stereoisomerism

Isomers which have same structural formula but have different relative arrangement or atoms or groups in space are called stereoisomers and the phenomenon is called stereoisomerism. cis-trans isomerism is an example of stereoisomerism. Due to π-bonding between the two carbon atoms, the rotation around carbon-carbon double bond is prohibited and hence the geometry of the atoms…

Structural Isomerism

Isomerism Two or more compounds having the same molecular formula but different chemical and physical properties are called isomers and the phenomenon is known as isomerism. It is of 2 types: 1) Structural isomerism 2) Stereoisomerism 1) Structural Isomerism : Compounds having the same molecular formula but different structures i.e. different arrangement of atoms within the…

Nomenclature For Di and Polyfunctional Aromatic compounds

1) When an aromatic compound contains two or more functional group, it is named as a derivative of the compound with the principal functional group at position 1. 4-Nitrobenzoic acid 2-Aminophenol 3-Acetylbenzonitrile 4-Iodo-2-methylphenol 3-Bromo-4-hydroxybenzoic acid 2) If all the functional groups present in the benzene ring are such which are normally treated as substituent group,…

Nomenclature of Simple aromatic compounds

Aromatic compounds contain one or more isolated or fused benzene rings.An aromatic compound consist of two parts : 1)Nucleus: The most ideal aromatic compound is benzene.It is represented by a regular hexagon of six carbon atoms with three alternate single and double bonds.This is called the nucleus.The ring may be represented by any of the following…

Rules For naming Alicyclic Compounds

The names of acyclic compounds are obtained by adding the prefix cyclo to the name of the corresponding straight chain hydrocarbons. 2) If two or more alkyl group or other substituent groups are present in the ring , their positions are indicated by arabic numerals 1,2,3,4 ….while numbering the carbon atoms of the rings ,…

Rules For IUPAC Nomenclature Of Polyfunctional Compounds

Organic compounds which contain two or more functional group are called polyfunctional compounds. The IUPAC names are obtained as follows: 1) Principal functional group : When an organic compound contains two or more different functional groups, one of the functional is selected as the principal functional group while all other groups are treated as substituents….

Rules For IUPAC Nomenclature Of Unsaturated Hydrocarbons

The parent chain must contain the multiple bond regardless of the fact whether it also denotes the longest continuous chain of carbon atoms or not. 2 If both double and triple bonds are present, the numbering of the parent chain should always be done from that end which is nearer to the double bond or…

Rules for IUPAC nomenclature of Branched chain alkanes

Longest chain rule: Select the longest continuos chain of carbon atoms.This is called the parent chain while all other carbon atoms which are not included in the parent chain are called branch chain or side chains or substituent.it may be noted that the longest chain may or may not be straight but it must be…

Functional Or Characteristic Group

Hydrocarbons are the parent organic compounds.All other compounds are considered to have been derived from them by replacing one or more of their hydrogen atoms by some other more reactive atom or group. R—H ——–> R—G -H and +G Each organic molecule consist of two parts i.e. R and G. The first part, i.e. R…