¥ 1. Chemistry basics Flashcards
What is an aliphatic compound?
A carbon backbone with one or more functional groups attached.
How do we number carbons in an aliphatic compound?
The longest chain starting from the carbon attached to the functional group that defines the molecule type.
List the names of the alkanes in order?
Alkanes: carbon to carbon single
Meth, eth, prop, but, pent, hex, hep, oct, non, dec
What are aromatic compounds?
6 carbon benzene ring with alternating single and double bonds.
What is a benzene ring with an OH called?
Phenol
What is valency?
The number of bonds an atom has in its uncharged state
What is a structure activity relationship?
When adding different function groups to a base molecule changes its characteristics e.g. more lipid soluble or convulsant effect
What are the two types of volatile agents?
Halogenated Ethers or halogenated hydrocarbons (halothane and chloroform)
What increases stability in volatile agents?
Potency?
Adding fluoride and having the ether group
Adding chloride or bromide
What are the three components of local anaesthetics?
All have an aromatic group at one end and an amine group at the other
The intermediate chains are either esters or amides
How are acids and bases defined?
Acid = proton donor
Base = proton acceptor
What is pH dependent ring closure?
When part of a molecule incorporates into a ring at a certain pH, closing the ring and therefore changing the molecules properties e.g. making it non-ionised and therefore lipid soluble.
What is tautomerization?
Example?
a net process by which protons are transferred from one site in a molecule to another by a series of steps in which the solvent is an intermediary.
Thiopental in alkali = ionised and water soluble due as an -enol by substituting a proton for an Na
At physiological pH: dissociates the sodium to bind to the proton, forming the unionised molecule as a ketone
Called keto-enol tautomerization
What is physiological pH?
7.4
What are the intra- and intermolecular bonds?
Intra = covalent, ionic, intermediate and Co-ordinate
Inter = VDW’s, dipole-dipole and hydrogen
What are ionic bonds?
Electrostatic attraction between oppositely charged ions produced by electron transfer between atoms. The more electronegative will steal an electron from the lesser one and become negatively charged.
2 ions:
Cation = donor (usually metal)
Anion = acceptor (usually non-metal)
Characteristics:
Strong = high mp and bp
Water soluble as ionic
Conduct electricity
What are covalent bonds?
Atoms that are similarly electronegative will share electrons (1 each)
The positively charged nuclei of each are attracted to the negative shared electron on the centre
Characteristics:
Usually non metallic
Often liquids or gasses with low BP and MP’s
What is coordinate bonding?
A covalent bond where 1 atom supplies both of their electrons instead of one each.
Atoms usually have a lone pair of electrons not involved in a bond.
What are intermediate bonds?
Polar covalent bond.
Between a covalent and ionic bond, where the electrons are shared, but one nuclei is more electronegative than the other and so will pull more electrons towards its side, making a slight, but not full charge. The degree of polarity depends on the electronegativity of the atom
How do we find out the electronegativity on the periodic table?
The closer the atom is to fluoride in the columns and periods (horizontal)
E.g. ore electronegative travelling from left to right and from bottom to top
What are VDW’s bonds?
The movement of an electron round an atom at high speeds causing temporary dipoles that can attract
What are dipole dipole interactions?
Permanent dipoles that exist in polar molecules e.g. intermediate bonds, that attract to each other
What is hydrogen bonding?
Hydrogen binding strongly to either O, Fl, or N (strongly electronegative).
Increases the polarity and so is the strongest type of dipole dipole interaction.
What are the strengths of the intra and intermolecular bonds, strongest to weakest?
Ionic
Covalent
Hydrogen
Dipole
VDW’s
What kind of an attraction must a drug have in order to bind to a receptor?
What kind of bonds does this require?
Form rapidly
Be strong enough to last long enough for the drug to exert its effect
Must exert its attraction from a distance
Ionic bonds can do 1 and 3, but needs extra bonds e.g. VDW’s or H to do number 2
What are the two ways covalent bonds can be broken?
Homolytic fission and heterolytic fission
What is homolytic fission?
Bonds break due to UV light or high temperatures
Each atom takes 1 electron and therefore has an unpaired electron and so are free radicals
What is heterolytic fission?
The more electronegative atom takes both of the electrons, forming two oppositely charged ions.
Electrophile = positively charged (lost the electrons). Will be attracted to an electron rich atom to form a new covalent bond
Nucleophile = negatively charged (gained electrons). Will make a new covalent bond with a positive ion.
C - C
Alkanes
C = C
Alkenes
H
/
- N
\
H
Amines
- OH
Alcohol
-Cl
- Br
- I
- F
Halides
O
II
—C — OH
Carboxylic acid
O
II
C
/ \
Ketones
O
II
C
/ \
NH2
Amides
— C — O — C —
Ethers
O
II
R — C — O —R
(Acid). (Alcohol part)
Esters
