Faculty of Biotechnology Organic Chemistry Chapter 2. Nomenclature of organic compounds. Dr. M. Abd-Elhakeem. Common names.
Faculty of Biotechnology OrganicChemistry Chapter 2 Nomenclature of organic compounds Dr. M. Abd-Elhakeem
Common names • The nomenclature of organic molecules started with common or traditional name depending mainly on the origin in the history of the science or the natural sources of the compound. • But the relationship of these names to each other is arbitrary, and no rational or systematic principles.
IUPAC System for Nomenclature • 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 Chemistry (IUPAC). • every possible organic compound should have a name according to a number of rules
1- The name of organic molecule is divided in to two parts Number of carbon atom Function group FUNCTIONAL GROUP – atom or group of atoms which gives an organic compound its characteristic chemical properties.
2- Put the lowest number that indicate the position of function group. 3-pentanone 2-pentyne 2-butanol
3- In case of branched chain (this means there is one principle chain or parent chain and substitutions) A-The tallest chain is the parent B- Substitution must take the lowest number
The main chain (or parent chain) must include the functional groupand so may not necessarily be the longest chain.
C- In case of more than one substitution the substituents with alphabetical priority has the lowest numbering D- Write name in alphabetical order 4- In case of presence of halogens (Cl, F, Br, I) write the name of the halogen (Chloro, Floro, Iodo, Bromo)
5- In Case of presence of two function groups. A- In case of alkane chain and alkene chain the alkene is the parent B- Alkane – cyclo alkane the larger is the parent C- Alkane, Alkene, alkyne – benzene the Benzene is the parent D- Benzene – any other group than the alkane, alkene, and alkyne Benzene is the substitution and called phenyl.
order of group priority is alkane –alkene- alkyne – amine – alcohol – ketone – aldehyde - acid
Aromatic compounds Mono-substituents:
Practice. . . CH3 OH CH3 CH2CH2C(OH)(CH3)2 4,4-dimethylcyclohexanol 2-methyl-4-phenyl-2-butanol
Primary, Secondary, Tertiary • A primary carbon has one other C directly bonded to it. • A secondary carbon is directly bonded to two other C’s. • A tertiary carbon is directly bonded to three other C’s. • Multivalent atoms are 1º, 2º, or 3º by bonding to C’s. • Univalent atom or group not really 1º, 2º, or 3º on its own - ID depends on type of carbon it is bonded to.