Organic Compounds: Drugs and Accelerants • Drugs such as methamphetamine are taken to increase alertness or energy. • Causes psychological and physical stimulation similar to adrenalin since they are chemically similar. • All hydrocarbons such as gasoline can undergo combustion with oxygen and release energy • 2 C8H18 + 25 O2 -> 16 CO2 + 18 H2O
What is an Organic Compound? (The symbol R represents a generic hydrocarbon)
Alkanes • Contain C and H only • Contains C-C single bonds in chains or rings • Has 4 single bonds to every carbon (C) atom • Name: chain length + -ane
Formulas of Alkanes • A single bond between two carbon atoms possesses free rotation which allows these molecules to have different conformations, or different orientations but this does not change its properties. • I, II, III, IV and V represent the same molecule, butane, shown in different orientations. • I-V are structural formulas, VI is an expanded structural formula and VII is a condensed formula of butane.
Skeleton and Line Formulas • Two additional types of structural representations are also sometimes used: skeleton and line structural formulas. • In a skeleton formula only the carbon atoms are shown. • In a line formula, a carbon atom is assumed to be present at every intersection and at the ends of zig-zag lines.
Learning Check A. What is the skeleton formula for: • What is its line formula? C. What is its structural formula?
Branched Chain Isomers • Isomers have the same molecular formula but different structures. • Example: pentane, C5H12, has 3 isomers each with a continuous chain of different lengths. (a) pentane (b) 2-methylbutane (c) 2,2-dimethylpropane
Cycloalkanes • Three or more C-C single bonds connected in a ring • Name: Cyclo + alkane chain • The 3D structure of C5 and higher cycloalkanes are NOT flat even if they are drawn that way
Alkenes and Alkynes • Contains C=C double or triple bonds (called π-bonds) • Have 2 or 3 bonds between carbons • Name: chain length + -ene or –yne • Alkenes can be embedded in rings and chains Cyclohexene and 2-pentene
Aromatic Compounds • Flat rings of six carbon atoms; C6H6 = benzene • C-C bonds are equal in length, NOT “localized” alternating double and single bonds • π-electrons are “delocalized” above & below the ring • C6H5- branch is called “phenyl”:
Alcohols • General Formula, R-OH; Name, chain length + -ol • The position of the -OH is indicated by its location on the carbon chain • The “hydroxyl” group is chemically similar to water and has “hydrogen bonding”, so small chain alcohols dissolve.
Properties of Alcohols Why is ethane insoluble in water and ethanol is not? Why is the solubility of pentanol lower than ethanol?
Ethers • General Formula, R-O-R • Name: short chain + -oxy + long chain + -ane • Ethers are polar with C-O bond but have no –OH group so they are less soluble than alcohols • An ether can be attached to, or embedded, in a ring
Learning Check Identify all the functional groups in the molecule of THC. B. Will this molecule be soluble in water?
Aldehydes & Ketones • Aldehyde: a C=O bond with the C also bonded to H • Name: chain length + -al • Ketone: a C=O bond with two R groups attached • Name: chain length + -one with the position of the carbonyl group identified by a number • C=O but no –OH makes them less soluble
Learning Check Identify all functional groups in each of the following:
Carboxylic Acids • General Formula: contains a C=O bond, a C-O bond and an -OH bond • Name: chain length + -oic acid • They are more soluble than alcohols and taste sour • They are weak acids that partially ionize: • CH3CO2H + H2O <---> CH3CO2-1 + H3O+
Esters • General Formula, RC(=O)OR; contains a C=O bond and a C-O bond and an -O-R bond • Name: chain bonded to C-O + chain with C=O + onate • Prepared by reacting a carboxylic acid and an alcohol • CH3CO2H + CH3OH ---> CH3CO2CH3 + H2O • They are less soluble than acids. • They smell fruity.
Esters Fats are esters made from glycerol and long chain carboxylic acids that are insoluble in water.
Amines • General Formula: R-NH2, R2NH or R3N • Name: each carbon chain is named in alphabetical order + amine is added at the end • They are less soluble in water than alcohols & acids. • They are weak bases that partially ionize: • CH3NH2 + H2O <---> CH3NH3+1 + OH- • Found in most drugs, they taste bitter.
Learning Check Identify all the functional groups in the molecule of cocaine:
Amino Acids and Amides • Amino acids have both an amine and carboxylic acid • Amides come from the condensation of a carboxylic acid and an amine • Amides contain a C=O group connected to an NH
Proteins • Amino acids held together by amide bonds are the building blocks of proteins