Organic synthesis Flashcards
What are the features of homologus series you should learn?
Functional group
Properties
Typical reactions
What are the features of alkanes?
C-C
Non-polar and unreactive
Radical substitution
What are the features of alkenes?
C=C
Non-polar, electron-rich double bond
Electrophilic addition
What are the features of aromatic compounds?
C6H5-
Stable delocalsied ring of electrons
Electrophilic substitution
What are the features of an alcohol?
Polar C-OH bond
Nucleophillic substitution and dehydration/elimination
OR Lone pair on O acts a nucleophile
Esterification and nucleophilic substitution
What are the features of halogenoalkane?
C-X
Polar C-X bond
Nucleophilic substitution or elimination
What are the features of amines?
C-NH2 or C-NR2
Lone pair on N is basic and can act as nucleophile
Neutralisation and nucleophilic substitution
What is the functional group of an amide?
-CONH2 or -CONHR
What are the properties of nitriles?
C-C≡N
Electron deficient carbon centre
Reduction or hydrolysis
What are the featrures of aldehydes/ketones? (carbonyls)
C=O
Polar C=O bond
Nucleophilic addition or reduction and aldehydes will oxidise
What are the features of carboxylic acids?
-COOH
Electron deficient carbon centre
Neutralisation or esterification or reduction
What are the features of an ester?
RCOOR’
Electron deficient carbon centre
Hydrolysis
What are the features of an acyl chloride?
-COCl
Electron deficient carbon centre
Nucleophilic addition-elimination or condensation (loses HCl) or Friedel-Crafts reaction
What is a synthetic route?
Way in which you react things in different steps to form the desired product
What should be included if exams ask you how to make compound from another in the exam?
Special procedures (e.g. refluxing)
Conditions needed (tempreature or catalyst)
Safety precautions (do in a fume cupboard)
What two things should be remembered in a synthetic route?
Stereoisomers
Safety
Why is making the correct stereoisomers imporant?
Different stereoisomers could have different properties
Mechanisms can cause different ones to form
What are the conditions of thermal cracking and what are the products?
1000ºC
70 atm
Long-chain alkanes → mostly alkenes
What are the conditions of catalytic cracking and what are the products?
500ºC
Slight pressure
Zeolite catalyst (hydrated aluminosilicate)
Long-chain alkanes → smaller aromatic hydrocarbons
What is reforming and what are the conditions?
Conversion of straight chain → cyclic → aromatic hydrocarbons
500ºC
Platinum catalyst
What is hydrogenation and conditions?
Alkene + H2 → Alkane
150ºC
Nickle catalyst
How do you convert an alkene to a diol?
Acidified KMnO4
20ºC
How do you convert an alkene to a dihalogenoalkane?
X2
20ºC
How do you convert an alkene to an alkane?
(hydrogenation reaction)
H2
Nickel catalyst
150ºC
How do you convert an alkene into an alcohol?
(hydration)
Steam
H3PO4 catalyst
300ºC
60-70 atm
How do you convert an alcohol to an alkene?
conc H3PO4
170ºC
How do you convert an alkene to a halogenoalkane?
HX
20ºC
How do you convert a halogenoalkane to an alkene?
KOH
Ethanol
Reflux
How do you convert an alkane to a halogenoalkane?
X2
UV light
How do you convert a halogenoalkane to an alcohol?
warm aqueous KOH + reflux
OR Mg, dry ether, carbonyl then dilute acid
How do you convert an alcohol into a halogenoalkane?
KBr, 50% H2SO4 at 20ºC for bromoalkane
PCl5, 20ºC OR HCl 20ºC for chloroalkane
Red phosphorus + Iodine refluxed in situ then distilled for iodoalkane
How do you convert an alcohol to an ester?
Carboxylic acid, acid catalyst and heat
OR acyl chloride
How do you convert an ester to an alcohol?
Dilute acid or alkali
Reflux
How do you convert a halogenoalkane to a nitrile?
KCN
Ethanol
Reflux
How do you convert a halogenoalkane to a carboxylic acid?
Mg, dry ether then CO2 then dilute acid
How do you convert a halogenoalkane to a primary amine?
XS ethanolic ammonia
Heat
How do you convert a primary amine to a more substituted amine?
Halogenoalkane
How do you convert a nitrile to a primary amine?
LiAlH4 then dilute acid
OR H2, Ni/Pt catalyst, high temp and pressure
How do you convert a nitrile to a carboxylic acid?
Dilute HCl
Reflux
How do you convert an alcohol to an iodoalkane?
Red phosphorus and I2 to make PI3 in situ
Reflux
How do you convert a primary alcohol into an aldehyde?
K2Cr2O7 & H2SO4
Heat
Distil for aldehydes
How do you convert a secondary alcohol into a ketone?
K2Cr2O7 + H2SO4
Reflux
How do you convert an aldehyde into a carboxylic acid?
K2Cr2O7 & H2SO4
Reflux
How do you convert a methyl ketone (RCOCH3) into a carboxylic acid?
I2 & NaOH
20ºC
How do you convert a carboxylic acid into a primary alcohol?
LiAlH4
How do you convert an aldehyde or ketone into the hydroxynitrile?
KNC & H+
OR HCN & ethanol at reflux
How do you convert an ester to a carboxylic acid?
Dliute acid or alkali
Reflux
How do you convert a carboxylic acid to an ester?
Alcohol
Acid catalyst
Heat
How do you convert a carboxylic acid to an acyl chloride?
PCl5
20ºC
How do you convert an acyl chloride into a carboxylic acid?
Cold H2O
How do you convert an acyl chloride into an ester?
Alcohol
20ºC
How do you convert an acyl chloride to make a primary amide?
NH3
20ºC
How do you convert an acyl chloride to make an N-substituted amide?
Primary amine
20ºC
How do you convert a benzene ring into a halobenzene?
X2
Halogen carrier
20ºC
What are the halogen carriers?
Aluminium halides
Iron halides
Iron
How do you convert benzene to a phenylketone?
Acyl chloride
AlCl3 catalyst
Reflux
How do you convert benzene into an alkyl benzene?
Halogenoalkane
AlCl3 catalyst
Reflux
How do you convert benzene into nitrobenzene?
conc HNO3 & conc H2SO4
Below 55ºC
How do you convert nitrobenzene into phenylamine?
Tin & conc HCl under reflux
Then NaOH
How do you convert a phenol to 2,4,6-tribromophenol?
Bromine water
20ºC