Functional Groups in Organic Compounds:

We have seen that alkanes, alkenes and alkynes are defined by the type of carbon-carbon bonds present in them. 

We can distinguish classes of organic molecules by "functional groups", which largely determine how they react with other compounds and some general properties

functional group - a specific arrangement of atoms in an organic compound that is capable of characteristic chemical reactions.

The carbon-carbon double bond is the functional group defines an alkene

The carbon-carbon triple bond is the functional group that defines an alkyne

If we move away from pure hydrocarbons, there are many more functional groups common to organic chemistry

Note:  -R is commonly used to represent a general alkyl substituent (e.g. methyl, ethyl, propyl, etc...)

1. Alcohols - contains the OH group (frequently used as antiseptics), general structure R-OH

CH3OH	Methanol - use the suffix ol to name alcohols (wood alcohol)
CH3CH2OH	ethanol
CH3CH2CH2OH	1-propanol - the number indicates the position of the -OH group.  Not necessary with methanol and ethanol because there is only one unique position.
	2-propanol (also called isopropyl alcohol and isopropanol - rubbing alcohol)

General formula: .  For example with ethanol R = CH₃CH₂-

2. Ethers:  General structure R-O-R^'

Name alkyl groups on both sides in alphabetical order - follow with ether

There are many more:  Here is a list of some additional functional groups, you should know the functional group characteristic of each type of organic compound and be able to recognize by the name of an organic compound  (just look at the ending suffix) what group it belongs to.

Name of Class	General Formula	Suffix	Example w/ systematic name.  (Common name in parenthesis)
Alkane	none	-ane	ethane,
Alkene		-ene	ethene (ethylene),
Alkyne		-yne	ethyne (acetylene),
Arene			benzene
Alcohol		-ol	ethanol,
Haloalkane (Alkyl halide)		"o" in place of "ine" in halogen name.	chloroethane (ethyl chloride)
Ether		-oxy- (not a suffix really)	methoxyethane more common naming scheme is to call this ethyl methyl ether
Aldehyde		-al	ethanal,
Ketone		-one	propanone (acetone),
Amine		-amine	methylamine,
Carboxylic Acid		-oic acid	ethanoic acid (acetic acid)
Ester		-oate	methyl ethanoate

Again, remember, functional groups play a major role in determining the physical and especially the chemical properties of organic molecules.  

Demo: Salicylic acid (aspirin) to oil of wintergreen:

	----------------> acid H2SO4, methanol
salicylic acid		wintergreen

Some examples of different fragrances mainly esters:

methyl butanoate	apple
ethyl butanoate	pineapple
propyl ethanoate	pear
pentyl ethanoate	banana
ethyl formate	rum
benzyl ethanoate	jasmine

Let's look again at the ingredients list for the mango.  You should be able to recognize molecules from many of the above classes.

a-Terpinolene, Ethyl butanoate, 3-Carene, Ethyl acetate, Ethyl 2-butenoate, a-Terpinene, a-Thujene, Dimethyl sulfide, Limonene, b-Phellandrene, Myrcene, p-Cymen-8-ol, b-Caryophyllene, cis-3-Hexene-1-ol, hexadecyl acetate, 5-Butyldihydro-3H-2-furanone, trans-2-hexenal, Ethyl tetradeconaoate, a-Humulene, Ssabinene, 2-Carene, Camphene, Ethyl octanoate, 4-Isopropenyl-1-methylbenzene 1-Hexanol, g-terpinene, hexanal, Ethyl hexadecanoate, a-Copaene, Hexadecanal, Ethanol, Ethyl propionate, Dihydro-5-hexyl-3H-2-furanone, Carveol, Geranial, Ethyl decanoate, Furfural, Butyl acetate, Methyl butanoate, 2,3, Pentanedione, 1,1, diethoxyethane, pentadecanal, Butyl formate, 1-Butanol, 5-Methylfurfural, Ethyl dodecanoate, 2-Acetylfuran, 2 Methyl-1-butanol, 4-Methylacetophenoen, Acetaldehyde, Cyclohexane

Many organic compounds belong to more than one class:

amino acids - contain a carboxylic acid functionality and an amine functionality.  Amino acids are used by the body to make proteins. Below is a structural formula for glycine, the simplest amino acid. 

Simple sugars such as glucose are polyhydroxyaldehydes.  The hydroxy indicates the OH group of the alcohol.  Below is a structural formula for glucose.