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Encyclopedia > Substituent

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. The suffix -yl (meaning "attached to") is used when naming organic compounds that contain a substituent. 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. The polar effect exerted by a substituent is a combination of the inductive effect and the mesomeric effect. Additional Steric effects result from the volume occupied by a substituent. Organic chemistry is a specific discipline within the subject of chemistry. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... In organic chemistry, a parent chain is the longest continuous chain of connected carbon atoms in a hydrocarbon. ... Hydrocarbons are refined at oil refineries and processed at chemical plants In chemistry, a hydrocarbon is any chemical compound that consists only of the elements carbon (C) and hydrogen (H). ... Benzene An organic compound is any member of a large class of chemical compounds whose molecules contain carbon, with the exception of carbides, carbonates, carbon oxides and elementary carbon. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. ... The Polar effect or electronic effect in chemistry is the effect exerted by a substituent on modifying electrostatic forces operating on a nearby reaction center. ... The inductive effect is associated with the dipole moment of the compound R-X. If X is at the negative end of a dipole moment, it will draw electrons from the ring and produce -I effect. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Steric effects are the interaction of molecules dictated by their shape and/or spatial relationships. ...


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.
  • Zaitsev's rule predicts that the major reaction product is the alkene with the more highly substituted (more stable) double bond.

In chemistry, Markovnikovs rule is an observation based on Zaitsevs rule. ... Zaitsevs rule or Saytzeffs rule named after A. N. Zaitsev is a rule in chemistry that states: If more than one alkene can be formed by an elimination reaction, the more stable alkene is the major product. ...

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. 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. The total number of organic substituents in organic chemistry is estimated at 3.1 million creating a total of 6.7x1023 molecules. Cheminformatics is the use of computer and informational techniques, applied to a range of problems in the field of chemistry. ... In chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the functional group with the formula -C6H5 Picture where the six carbon atoms are arranged in a cyclic manner. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... In chemistry, the methoxy prefix indicates the function group consisting of the methyl group and oxygen. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Ethyl is a two-carbon substituent in organic chemistry. ...


See also

In organic chemistry functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those 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. Chem. Inf. Comput. Sci.; 2003; 43(2) pp 374 - 380 Abstract Download reprint

  Results from FactBites:
 
Substituent - Wikipedia, the free encyclopedia (310 words)
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.
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.
The polar effect exerted by a substituent is a combination of the inductive effect and the mesomeric effect.
Nomenclature Examples (1823 words)
When one substituent and one hydrogen atom are attached at each of more than two positions of a monocycle, the steric relations of the substituents may be expressed by first identifying a reference substituent (labeled r) followed by a hyphen and the substituent locator number and name.
When two different substituents are attached at the same position of a monocycle, then the lowest-numbered substituent named as a suffix is selected as reference group.
If none of the substituents is named as a suffix, then that substituent of the pair of substituents having the lowest number, and which is preferred by the sequence rule, is chosen as the reference group.
  More results at FactBites »

 
 

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