Chapter 28 - Organic Synthesis Flashcards
Carbon-carbon bond formation, Further practical techniques, Further synthetic routes.
what are nitriles?
nitrile groups are shown as CN its a C≡N bond
how are nitriles formed from haloalkanes? what’s the mechanism?
Nitriles can be formed by reacting haloalkanes with cyanide CN- ions in ethanol.
how do you prepare hydroxynitriles from carbonyl compounds? what’s the mechanism?
hydrogen cyanide, HCN adds across the C=O bond of aldehydes and ketones to form hydroxynitrile. HCN is generated in the solution from sodium cyanide, NaCN and sulfuric acid, H2SO4. The reaction mechanism is nucleophilic addition.
reduction of nitriles equation? and conditions
Nitriles are reduced to amines with hydrogen in the presence of a nickel catalyst.
R-C≡N = R-CH2NH2
nitrile to amines by reduction
CH3CH2CH2C≡N + 2H2 = CH3CH2CH2CH2NH2
butanenitrile butylamine
hydrolysis of nitriles equation?
R-C≡N to R-COOH
nitriles to carboxylic acids by hydrolysis
CH3CH2CH2C≡N +2H2O+HCl =CH3CH2CH2COOH+NH4Cl
butanenitrile butanoic acid
how is a carbon-carbon bond is formed to an aromatic ring?
A carbon-carbon bond is formed to aromatic ring by
1) alkylation, with a haloalkane, RBr Ar to Ar-R
2) alcylation with acyl chlrodie, RCOCl Ar to Ar-COR
how do you purify an organic solid?
1) filter under reduced pressure
2) recrystallisation
3) measurement of melting points
how to filter under reduced pressure? what equipment is necessary?
filtering under reduced pressure is a technique for separating a solid product from a solvent or liquid reaction mixture.
1) buchner flask
2) buchner funnel
3) pressure tubing
4) filter paper
5) access to filter or vacuum pump connected to a tap
how does recrystallization work? what is it reliant on?
the filtered product contains impurities these ar removed by recrystallisation.
the technique relies on two things
1) The desired product is less soluble than soluble impurities in the chosen solvent
2) solubility is greater in a hot solvent than a cold solvent
the stages are:
1) minimum volume of hot solvent is added to dissolve impure solid
2) the resulting solution is cooled allowing the product to recrystallise out the solution
3) the crystals are filtered under reduced pressure and dried to obtain a pure sample
how does melting point determination work?
we can check the purity of a solid by chekcing its melting point
1) a sample of the pure compound is placed in the bottom of the sealed capillary tube
2) the melting point is measure using an electric melting point apparatus or a Thiele tube
write down the reactions of the aliphatic functional groups. hint it looks like a spiderweb diagram
write down the reactions of the aromatic functional groups on benzene. hint it looks like a spiderweb diagram
write down the reactions of the aromatic functional groups on phenol. hint it looks like a spiderweb diagram
how to suggest a multi stage synthetic route?
