Dr. M. Abd-Elhakeem Faculty of Biotechnology Organic Chemistry Chapter 2

 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.

 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).systematicorganic chemical compoundsInternational Union of Pure and Applied Chemistry  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.

Second partFirst part Function groupNo of carbon atoms  Alkane ane  Alkene ene  Alkyne yne  Alcohol anol  Aldehyde anal  Ketone anone  Acid anoic  Substitution yl 1. meth 2. eth 3.prop 4. but 5. pent 6.hex 7.hept 8. oct 9. non 10. dec In case of cyclic form add firstly cyclo-

Propene Propanol

3-pentanone 2-pentyne2-butanol 2- Put the lowest number that indicate the position of function group.

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

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)

order of group priority is alkane – alkene- alkyne – amine – alcohol – ketone – aldehyde - acid

3-hydroxy-pentanoic acid

Mono-substituents:

Di-substituents

Practice... OH CH 3 CH 2 CH 2 C(OH)(CH 3 ) 2 4,4-dimethylcyclohexanol 2-methyl-4-phenyl-2-butanol

 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.