Organic synthesis Flashcards
Why do you try and keep the number of steps as low as possible ?
To improve the percentage yield of the final product.
What could cause the yield of an individual step to be low ?
2
- product could be left in the reaction mixture each time / inefficient separation
- incomplete/reversible reactions
What is the main oxidising agent used inorganic chemistry ?
Acidified potassium dichromate
K2Cr2O7 / H2SO4
What are primary alcohols oxidised into ?
Aldehydes, then carboxylic acids
- using acidifies potassium dichromate
- heat
What are secondary carboxylic acids oxidised to ?
Ketones
- reduction
- acidified potassium dichromate
- heat
What reduces C=O
NaBH4
H- attacks the C+
What reduces C=C
H2 and Nickel
What reduces NO2 to NH2
Tin / HCl
What are the 2 main dehydrating agents
Al2O3. ( vapours pass over it )
Acid catalysed elimination by H3PO4
What does a compound being solid indicate ?
Long chain C or ionic
What does a compound being a gas indicate ?
Short carbon chain or non polar-bonds
What does a smoky flame when burnt suggest?
High C:H ratio, possibly aromatic
Alkene ——> alkane
Hydrogenation (electrophilic addition)
- high temp - 200
- Ni catalyst
- H2
Alkene ——> haloalkane
Electrophilic addition.
- halogen HX or X2
Haloalkane ——> Alkene
Elimination
- warm
- ethanol
- NaOH or KOH
Alkene ——> alcohol
Electrophilic addition
- conc. H3PO4
- add water
Alcohol ——> Alkene
Elimination
- H2SO4
- hot - 200
Alkene ——> Alkyl hydrogen sulphate
Electrophilic addition
- conc. H2SO4
Alkyl hydrogen sulphate ——> alcohol
Hydrolysis
- add H2O
- heat
Alkane ——> haloalkane
Free radical substitution
- halogens
- UV light
Haloalkane ——> Amine
Nucleophilic substitution
- NH3
- heat
Amine ——> Amide
nucleophilic addition elimination
- acyl chloride or acid anhydride
Haloalkane ——> Nitrile
Nucleophilic substitution
- KCN
- ethanol
- heat
Nitrile ——> Amine
Reduction
- H2
- Ni catalyst
- heat - 200
