organic chemistry Flashcards
what are hydrocarbons?
organic compounds that contain only carbon and hydrogen there are aliphatics and aromatics
what bonds do alkanes have?
-they contain sigma bonds
what is the bond angle of alkanes?
109.2
what happens to cyclic alkanes if they’re flat?
they are forced out of the most favourable angles causing angular strain
what type of strain can be caused due to cycloalkanes being flat?
-torsional strain because they are forced into a more eclipsed formation
-to overcome the instability, large chains e.g cyclohexanes can pucker their shape to minimise the effects
what are the physical properties of alkanes/cycloalkanes?
-they are insoluble in aqueous solutions e.g.plasma
-they are insoluble in non-aqueous media e.g lipids in the body which contain long hydrocarbon backbones
-they are rapidly passed from the bloodstream into the nervous system and brain (which contain lipids),at low cons this can=hallucinations at higher concs they can cause a loss of consciousness and in extreme cases death
how is cyclopropane used as a general anaesthetic? (chemical properties of alkanes/cycloalkanes)
-it is mixed with oxygen which allows it to be used as a general anaesthetic, the absorption of cyclopropane is reversible so its effects will wear off
what does the fractional distillation of crude oil lead to? (chemical properties of alkanes/cycloalkanes)
the fractional distillation leaves a high boiling point residue called paraffin and liquid paraffin is used as a laxative since it aids lubrication and is not absorbed in its passage through the body
what is paraffin used for in pharmaceutical products?
-used as moisture resistant base for ointments and bases, its also used for vaseline
what is the structure of alkenes/cycloalkenes structure?
-unsaturated
-sigma and pi bond, the pi electrons are held less tightly
-have a planar structure
-E/Z isomerism sometimes occurs
what are the 4 major reactions alkenes/cycloalkenes undergo?
addition, oxidation,reduction,polymerisation
why are alkenes/cycloalkenes poorly soluble in aqueous environments?
-there is no ability to form a hydrogen bond or form polar interactions
what do alkenes undergo oxidation reactions with?
-cold KMnO4
-hot KMnO4
-Ozone (O3)
what can alkenes be reduced by?
hydrogen in the presence of a Pd catalyst
what is the structure of aromatic hydrocarbons?
-they are flat, conjugated cyclic hydrocarbons
-they are only aromatic if they follow huckles rule
what is huckles rule?
”for a cyclic compound to be aromatic it must have 4n +2 pi electrons where n must be a whole number
what is a physical property of aromatic hydrocarbons?
-they are insoluble in aqueous environments and soluble in non-aqueous environments
what are the chemical properties of aromatic hydrocarbons?
-they are more stable than alkenes
-they are resistant to oxidation,reduction and addition-this is because these reactions would result in a loss of aromaticity
-they undergo substitution reactions since with them aromaticity can be maintained e.g electrophilic substitution reactions-friedel crafts acylation and alkylation
what is a biological property of aromatic compounds?
-non-functionalised aromatic hydrocarbons have very little use as drugs but substitued aromatic compounds form the basis of many drugs e.g aspirin and paracetamol.
what are spirocompounds?
-bicyclicalkanes which have two rings sharing only one carbon
how do you distinguish between spirocompunds?
-if spirocompounds have the same total number of carbons but different number of carbons in each ring, the number of carbons in each ring (excl the central carbon) is placed in square brackets with a dot between them
-the numbers always go from low to high
how do you name substituted spirocompounds?
-when there are substitutes on the ring, you first start by numbering the smaller ring next to the ring junction and go around this ring through the ring junction and then into the larger ring
-you go in the direction which put the substitutes with the lowest number in each ring
what are bridgehead compounds?
-compounds where two rings of the bicyclic compound have two carbons common
how are bridgehead compounds named?
-they are given the prefix bicyclo
-the root name is based on the total number of carbons in the bicycle
-the stereochemistry is described in brackets with three numbers describing the number of intervening carbons between the two bridgehead carbons in decreasing order e.g bicyclo[4,2,2]decane
what are the steps for numbering substituents on bridgehead compounds?
-start with one of the bridgehead carbons and label it
-proceed around the longest chain of carbons to the second bridgehead
-number the second bridgehead carbon and continue around the next longest chain of carbons back towards the first bridgehead carbon
-pass over the first bridgehead carbon as its already been labelled and along the final, shortest chai of carbons to the second bridgehead
what can functional groups on a compound affect?
-acid/base properties
-water solublility/lipid solubility
-shape/stereochemistry-interaction with in vivo targets
this can all effect ADME and toxicity and side effects
what is ADME?
-absorption,distribution,metabolism and excretion
what is the bond angle of alkanes?
-usually 109.2
what type of bonds do alkanes contain?
sigma
what could occur if cyclicalkanes were flat?
-they would be forced out of most favourable angles causing angular strain
-torsional strain could also occur due to being forced into a more eclipsed confirmation
what do some cycloalkanes do because of instability?
-larger chain cycloalkanes,pucker their shape
when are alkanes insoluble?
-in aqueous environments e.g plasma
when are alkanes soluble?
in non aqueous media such as lipids in the body which contain long hydrocarbon backbones
what is a physical property of alkanes?
-they are rapidly passed from the blood stream into the nervous system and brain (which contain lipids). -at low concentrations this can cause hallucinations. At higher concentrations they can cause loss of consciousness, and in extreme cases death.
what chemical reactions can alkanes undergo?
-combustion
-halogenation
(learn equations)
what is a medicinal use of the alkane cyclopropane?
-cyclopropane can be mixed with oxygenated dn be used as a general anaesthetic and the absorption of cyclopropane is reversible so its effects will wear off
how is paraffin made and what is it use?
medicinal use of alkanes
-fractional distillation of crude oil leaves the high boiling point residue paraffin
-liquid paraffin is used as a laxative since it aids lubrication and is not absorbed in its passage through the body
-paraffin is also used in many pharmaceutical products as a moisture resistant base for ointments and creams
-vaseline is a soft yellow paraffin wax
what is the structure of alkenes?
-unsaturated
-contain a sigma and pi bond nd the pi electrons are held less tightly
-they have a planar structure
what are the 4 major reactions alkenes can undergo?
alkenes are more chemically reactive than alkanes and so can undergo
-addition reactions
-oxidation reactions
-reduction reactions
-polymerisation reactions
what does the oxidation of alkenes require?
either
-cold KMNO4 or hot KMnO4 or ozone
what is needed for the reduction of alkenes?
-hydrogen in the presence of a Pd catalyst
what rule does a hydrocarbon need to follow to be aromatic?
-huckles rule which states that for a cyclic compound to be aromatic it must have 4n + 2 pi electrons where n must be a whole number
what is a physical property of aromatic hydrocarbons?
-they are insoluble in aqueous environments and soluble in non-aqueous environments
what are the chemical properties of aromatic hydrocarbons?
-they are more stable than alkenes
-they are resistant to oxidation, reduction and addition since all of these would result in a loss of aromaticity
-they undergo substitutions reactions since aromaticity can be maintained
what is an example pot the reactions aromatic hydrocarbons can undergo?
-electrophillic substitution reactions in which there is is Friedal crafts acylation and alkylation
what is a biological property of aromatic hydrocarbons?
-non functionalist aromatic hydrocarbons have very little use as drugs but substituted aromatic compounds form the basis of many drugs e.g aspirin and paracetamol
what is the hydroxyl functional group?
-OH
-hydroxyl groups bound to an aliphatic carbon=alcohol
-hydroxyl group bound to an aromatic carbon=phenol
what are the physical properties of alcohol and phenols?
-they hydrogen bond with water and this adds to the water solubility
-solubility increases as the ratio of polar to non polar structure increases
-in-vivo the solubility effects interaction in the body and leads to faster clearance from the body
what are the chemical properties of alcohols and phenols?
-they act as weak acids in water as the electronegative oxygen is able to support a negative charge
why are phenols slightly more acidic than alcohols?
-the negative charge can be stabilised by the aromatic ring and this means there is increased stability of the phenolate ion
what are the biological properties of alcohols and phenols?
-they are found in many drugs
-they can be susceptible to fast metabolism in vivo due to their reactivity and example is fluvasatin
what does fluvastatin do?
-blocks the liver enzyme HMG-CoA reductase involved in cholesterol synthesis and is used to treat hypercholesterolemia
what are the physical properties of thiols and thiophenols?
-they are often vile smelling and are less soluble than corresponding alcohols and phenols due to weaker hydrogen bonding ability
what are the chemical properties of thiols and thiophenols?
-the are stronger acids than alcohols and phenols as there is less overlap of the SH sigma bond
-they are better nucleophiles since the loan pair is held onto less tightly
what are the biological properties of thiols and thiophenols?
-they are more easily oxidised and this occurs in the air affecting the shelf life of drugs
-they are seen in many drugs such as olanzapine(used for schizophrenia) and dimercaprol (which is used to treat toxic exposure to metals like gold, lead,mercury)
what is the structure of aldehydes and ketones?
-they both contain the carbonyl group
-the carbon of the carbonyl group is sp2 hybridised and the functional group is planar in structure
what is the physical structure of aldehydes and ketones?
-they are less soluble than similar sized alcohols and phenols but are polar and can take part in hydrogen bonding
what are the chemical properties of aldehydes and ketones?
-they undergo many reactions and ketones are reasonable stable in vivo unlike aldehydes
-ketones are found in any natural occurring compounds and drugs e.g warfarin which is an anticoagulant that prevents the formation of blood clots
what is the structure of carboxylic acids?
-they contain an sp2 carbon but next to a hydroxyl group
what are the physical properties of carboxylic acids?
-they are very polar and can hydrogen bond to small molecules and tend to be water soluble
what are the chemical properties of carboxylic acids?
-they are acidic,they are stronger than phenols but are still weak acids
-their polarity (in vivo) is influenced by the pH of the body
-the COOH is a very reactive functional group in vivo
what is the biological property of carboxylic acids?
-they occur widely in nature and are very present in many drugs e.g aspirin,ibuprofen
what is the structure of amines?
-there are primary amines (2 hydrogens),secondary amines (1 hydrogen) and tertiary amines (no hydrogens)
-the nitrogen in amines are sp3 hybridised and nitrogen forms 3 sigma bonds and has one loan pair of electrons, the shape is tetrahedral
what is a physical property of amines?
-simple low mass amines are often water soluble, they can hydrogen bond to water and each other
what are the chemical properties of amines?
-the loan pair on the nitrogen allows them to act as a base (portion acceptor)
-they are also good nucleophiles which make them quite reactive
-free amines are quite reactive and unstable
what are some examples of drugs that contain the amine functional group?
-lisinopril-used for high blood pressure
-morphine-pain medication
what is the structure,physical and chemical properties of amides?
-they are not basic due to the conjugation of the loan pair in the nitrogen into the carbonyl group and they tend to behave as a neutral functional group
-due to limited ability to hydrogen bond they tend to be less soluble than similar sized amines
-they are chemically stable
what is the structure of amino acids?
-they contain both a carboxylic group (COOH) and an amine group (Nh2)
-they tend to exist as a zwitterion
what are the physical properties of amino acids?
-they tend to be water soluble
-charges vary according to the pH of the solution they are in
-the pH at which amino acids exist as zwitterions is known as the isoelectric point
what are the chemical properties of amino acids?
-the chemical reactions are very diverse and they can form peptide bonds with each other to form polypeptides (proteins)
what are the biological properties of amino acids?
-they are the building blocks of proteins
-proteins have multiple roles in the body i.e enzymes and receptors
-amino acids are both targets for drugs and van be drugs
-the variability of the R group in natural a amino acids gives them diverse physical,chemical and biological activities
