In organic chemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 The IUPAC nomenclature of organic chemistry is a systematic method of naming organic chemical compounds as recommended by the International Union of Pure and Applied In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. The suffix -yl (meaning "attached to") is used when naming organic compounds that contain a substituent. An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Additionally, when naming hydrocarbons that contain a substituent, positional numbers are used to indicate which carbon atom the substituent is attached to when such information is needed to distinguish between structural isomers. This article is about the chemical concept For "isomerism" of atomic nuclei see Nuclear isomer. The polar effect exerted by a substituent is a combination of the inductive effect and the mesomeric effect. The Polar effect or electronic effect in Chemistry is the effect exerted by a Substituent on modifying Electrostatic forces operating on a nearby The inductive effect in Chemistry is an experimentally observable effect of the transmission of charge through a chain of Atoms in a Molecule The mesomeric effect or resonance effect in Chemistry is a property of Substituents or Functional groups in a Chemical compound. Additional Steric effects result from the volume occupied by a substituent. See also Intramolecular forces ' Steric effects arise from the fact that each Atom within a Molecule occupies a certain

The phrases most-substituted and least-substituted are frequently used to describe molecules and predict their products. For example:

• Markovnikov's rule predicts that the hydrogen adds to the carbon of the alkene functional group that has the greater number of hydrogen substituents. In Chemistry, Markovnikov's rule or Markownikoff's rule is an Observation based on Zaitsev's rule.
• Zaitsev's rule predicts that the major reaction product is the alkene with the more highly substituted (more stable) double bond. In Chemistry, Zaitsev's rule, Saytzeff's rule or Saytsev's rule named after Alexander Mikhailovich Zaitsev (number of different spellings due

Contents 1 Number crunching 2 See also 3 External links 4 References

Number crunching

One cheminformatics study ^[1] identified 849,574 unique substituents up to 12 non-hydrogen atoms large and containing only C,H,N,O,S,P,Se and the halogens in a set of 3,043,941 molecules. Cheminformatics (also known as chemoinformatics and chemical informatics) is the use of computer and informational techniques applied to a range of problems 50 common substituents are found in only 1% of this set and 438 in 0. 1%. 64% of the substituents are unique to just one molecule. The top 5 consists of the phenyl, chlorine, methoxy, hydroxyl and ethyl substituent. In Organic chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the Functional group with the formula - Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and In Chemistry (particularly Organic chemistry) methoxy refers to the Functional group consisting of a Methyl group bound to Oxygen Hydroxyl in Chemistry stands for a molecule consisting of an Oxygen atom and a Hydrogen atom connected by a Covalent bond. The total number of organic substituents in organic chemistry is estimated at 3. 1 million creating a total of 6. 7×10²³ molecules.

See also

• Functional groups are a subset of substituents
• Side chain

External links

• Database of 21,000 substituents and 49,000 linkers extracted from bioactive molecules

References

1. ^  Cheminformatics Analysis of Organic Substituents: Identification of the Most Common Substituents, Calculation of Substituent Properties, and Automatic Identification of Drug-like Bioisosteric Groups Peter Ertl J. In Organic chemistry, functional groups are specific groups of Atoms within Molecules that are responsible for the characteristic Chemical reactions A side chain in Organic chemistry and Biochemistry is a part of a Molecule that is attached to a core structure Chem. Inf. Comput. Sci. ; 2003; 43(2) pp 374 - 380 Abstract Download reprint

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