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IUPAC NOMENCLATURE : SOME BASIC RULES

1.The four components of IUPAC name are:Prefix(subst) Word root(meth, eth, etc) Pri. Suffix (ane/ene/yne) Sec Suffix(main group)[Note : if the name of sec. suffix starts with a vowel then pri suffix will be : an / en / yn ]

2. locate the longest carbon chain by giving the preference as :functional group > double bond > triple bond > substituent / side

chain

3.follow lowest some rule also4.In a molecule the main group will be named as suffix. All the other groups

will be written alphabetically as prefixes

5.Prefix and suffix names of the functional groups with decreasing priority:Sl

No

Class of

Compound

Functional

Group

Structural

formula

Prefix Suffix

1 SulphonicAcid

- SO3H sulphonicacid

2 Carboxylic

Acid

- COOH carboxy oic acid

3 Acid

Anhydride

-

CO.O.CO-

oic

anhydride

4 Ester - COOR alkoxy

carbonyl

oate

5 Acid Halides - COX haloformyl oyl halide6 Amides -CONH2 carbamoyl amide

7 Nitriles - CN cyano nitrile

8 Aldehyde - CHO formyl al

9 Ketone >C=O oxo / keto one

10 Alcohol - OH hydroxy ol

11 Amines - NH2 amino amine

The following groups are always treated as substituent / side chain ( prefix) and written alphabetically

Group Name(Prefix)

- Br Bromo

- Cl Chloro

- OCH2CH3 Ethoxy

- F Fluoro

- I Iodo

- OCH3 Methoxy

- NO2 Nitro

- NO Nitroso

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