Book chapter 14 Pages 472511 Carbon atom of a carbonyl group is attached to a hydroxyl group forming a carboxyl group As functional group attached to an alkyl group or an aromatic group IUPAC names ID: 908502
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Slide1
Lecture 13:Carboxylic Acids, Esters, Amines and Amides
Slide2Book chapter: 14Pages: 472-511
Slide3Carbon atom of a carbonyl group is attached to a hydroxyl group forming a carboxyl groupAs functional group – attached to an alkyl group or an aromatic group
Slide4IUPAC namesReplace e of the alkene with oic acid
If there are substituents – the carbon chain is numbered beginning with the carboxyl carbon
Slide5Common names of carboxylic acidsUse prefixes: form, acet, propion, butyrRelate to the natural sources of the simple carboxylic acids
Slide6Properties of Carboxylic acidsMost polar organic compounds – functional group consists of two polar groups (-OH) and (C=O)Solubility in water:
Acids with 1-5 C atoms are soluble in waterLength increases – the nonpolar portion reduces the solubility of acid in waterMore than 5C atoms – not very soluble in water
Slide7Acidity of Carboxylic Acids:Importnat property: ionization in waterHydrogen ion is transferred to a water molecule – forming of negatively charged cyrboxylate ion and hydronium ionGenerally those acids are more acidic than most other organic compounds
Weak acids; 1% of the acid molecules ionize in water
Slide8Neutralization of Carboxylic Acids:Completely neutralized by strong bases (NaOH or KOH)Products: carboxylate salt and water
Slide9Chemistry Link to Health:Carboxylic Acids in MetabolismSeveral are part of metabolic processes
Example: glucose is broken down into two molecules of pyruvic acid or actually its carboxylate ion pyruvate (glycolysis)Pyruvic acid is reduced to give lactic acid (lactate ion)
Slide10EstersCarboxylic acid + alcohol -> ester + water-H of cyrboxylic acid is replaced by an alkyl group
Esters contained in fats and oils (esters of glycerol and fatty acids)
Slide11EsterificationProduction of estersIn the rpesence of an acid catalyst (H2SO4) and heat-OH group (carboxylic acid) and –H (alcohol) -> combined to form water
Slide12Naming estersTwo words – derived from the names of the alcohol and the acidFirst word – indicates alkyl part from the alcohol
Second word – name of the carboxylate from the carboxylic acid
Slide13Chemistry Link to Health:Salicylic acid from a Willow Tree
In the past people were chewing the leaves or piece of bark of the willow treeRelief from painLater (1800s)– salicin was discovered
Has carboxyl and hydroxyl group - irritates the stomach lining
1899 – ester of salicylic acid and acetic acid – aspirin
Less irritating, used as analgesic and anti-infammatory agent
Slide14Esters in plantsFragnances of perfumes and flowers or fruits – estersSmall esters are volatile – smell and soluble in water; taste them
Slide15Hydrolysis of EstersAcid HydrolysisHeating of esters with water in presence of a strong acid Wate
r reacts with the ester to form a cyrboxylic acid and an alcoholReverse of esterification reaction
Slide16Base Hydrolysis of EstersEsters undergo hydrolysis with a strong baseProducts: Carboxylate salt and corresponding alcohol
Saponification
Slide17AminesDerivatives of ammonia (NH3)One or more hydrogen atoms are replaced with alkyl or aromatic groups
Slide18Naming and Classifying AminesCommon names are often used when alkyl groups bonded to the nitrogen atom are not branchedGroups are listed in alphabetical orderPrefixes
di and tri indicate substituentsClassified – by counting the number of C atoms directly bonded to the nitrogen atom
Slide19Primary (1°) amine – nitrogen bonded to one alkyl groupSecondary (2°) amine – 2 alkyl groups
Tertiary (3°) amine – 3 alkyl groups
Slide20Aromatic aminesUse the name aniline
(approved by IUPAC)Alkyl groups attached to the nitrogen are named with the prefix N- followed by the alkyl name
Aniline – used to make dyes (indigo)
Give color to wool, cotton, silk fibers and blue jeans
Slide21Skeletal formulaSimilar like for other organic compoundsWe show the hydrogen atoms bonded to the N atom
Slide22Chemistry Link to Health:amines in Health and MedicineHistamine – in response to injury or allergy
Causes blood vessels to dilate and increases the permeability of the cellsRedness and swelling in the areaAntihistamines
– block the effect of histamine
Slide23In the body – biogenic amines (hormones)Carry messages between CNS and nerve cellsExamples: epinephrine (adrenaline) and norepinephrine (noradrenaline)Released by adrenal medulla in “fight or flight” situations
Raise the blood glucose level and move the blood to the muscles
Slide24Amphetamines – produced syntheticallyStimulants of the CNS Also increase cardiovascular activity and depress the appetiteSometimes used to bring about weight loss; can cause chemical dependency
Slide25Solubility of amines in waterContain polar N-H bond – form hydrogen bonds with waterPrimary form more bonds with water than secondaryTertiary only with N atom in the amine
Slide26Amines react as bases in water:Ammonia acts as base because it accepts H+ from waterProduces ammonium ion (NH4+) and hydroxide ion (OH-)
Slide27Ammonium salts:Example: lemon jiuce on the fish – revomes “fishy” odor by converting amines to their ammonium saltsNeutralization reaction – amines (base) react with an acid to form
ammonium saltNaming: using alkylammonium ion name followed by the name of the negative ion
Slide28Properties of Ammonium Salts:Ionic compounds Solids at room temperature, odorless and soluble in water and body fluidsAmines used as drugs are usually in form of these salts
If it reacts with a strong base – converted back to the amine
Slide29Heterocyclic aminesCyclic compoundContains one or more nitrogen atoms in the ringThe heterocyclic amine ring consists of 5 or 6 stoms and one or more nitrogen atoms
Slide30Chemistry Link to Health:AlkaloidsActive compounds produced by plants
Contain heterocyclic aminesAlkaloid - “alkali-like” or basic characteristicsSome of them used in anesthetics, antidepressants and stimulants
Examples
:
nicotine
and
caffeine
Slide31Several alkaloids – used in medicine Atropine – from nightshade; used to accelerate slow heart ratesCodeine – poppy plant; painkillerHeroin – chemical modification of morphine; not used medically (strongly addictive)
Slide32AmidesDerivatives of cyrboxylic acids Nitrogen replaces hydroxyl grouop
Slide33Preparation:Amidation reaction – carboxylic acid reacts with ammonia or primary/secondary amine
Slide34Naming:Dropping the oic acid or ic acid
and adding the suffix amideIf alkyl group is attached to the nitrogen atom – prefix N- or
N,N
- precedes the name of the amide
Slide35Solubility in water:Do not have properties of bases Amides with one to five C atoms are soluble in water (they can hydrogen bond with water molecules)More than five C atoms – effect of hydrogen bonding is diminished; longer carbon chain decreases the solubility
Slide36Chemistry Link to Health:Amides in Health and MedicineSimplest amide – urea (end product of protein metabolism)
Removed by kidenys Malfunction of kidneys – urea is not removed; uremiaUsed also as fertilizer to increase nitrogen in the soil
Slide37Barbiturates – act as sedatives in small dosages or sleep inducers in larger dosagesAspirin substituetes contain phenacetin – used in TylenolReduces fever and pain, has little anti-inflammatory effect
Slide38Slide39SummaryCarboxylic acidsProperties of carboxylic acidsEstersAcid/Base Hydrolysis of esters
AminesReaction of amines in waterAmmonium saltsAlkaloids
Amides