21. Organic synthesis
A section of Chemistry, 9701
Listing 10 of 83 questions
Noradrenaline is a hormone and neurotransmitter, which is released during stress to stimulate the heart and increase blood pressure. HO OH NH2 HO noradrenaline State the names of three functional groups in the noradrenaline molecule. Consider the following two-stage synthesis of noradrenaline from dihydroxybenzaldehyde. HO OH NH2 HO HO H O HO step 2 step 1 dihydroxybenzaldehyde noradrenaline Z ● Draw the structure of the intermediate Z in the box. ● Suggest reagents for steps 1 and 2. step 1 step 2 Dihydroxybenzaldehyde reacts with Br2. ● Describe what you would see during this reaction. ● Draw the structure of the product. Draw the structures of the products when noradrenaline is reacted with dilute NaOH, dilute HCl , an excess of ethanoyl chloride, CH3COCl. Name the new functional groups formed in the reaction in .
9701_s14_qp_43
THEORY
2014
Paper 4, Variant 3
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The anti-inflammatory drug ibuprofen can be synthesised from benzene via the following six steps. step 1 step 5 step 2 step 3 H J step 4 OH CN CO2H step 6 CO2H ibuprofen Draw circles around any chiral carbon atoms in the above five formulae. Suggest the structures of compounds H and J and draw them in the boxes above. Suggest reagents and conditions for steps 1-6. step 1 step 2 step 3 step 4 step 5 step 6 Name the mechanism of step 1 and state the type of reaction for step 6. step 1 step 6
9701_s16_qp_42
THEORY
2016
Paper 4, Variant 2
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Phenol is an important industrial chemical used in the manufacture of dyestuff and other substances. Suggest two different substances that react with phenol to produce potassiumphenoxide, C6H5O– K+. Identify the second product formed in each case. substance second product substance second product OH 2-naphthol 2-naphthol can show similar properties to phenol. It can be used to produce Sudan I, an orange coloured dyestuff. N OH N Sudan I On the diagram of SudanI above circle the bond or bonds that make this substance a dyestuff. Describe how SudanI can be made using phenylamine and 2-naphthol as the organic starting materials. Phenol can be used to make 2-nitrophenol. OH 2-nitrophenol NO2 The nitration reaction of phenol to form 2‑nitrophenol shows that phenol is more reactive than benzene. Describe the conditions used for the nitration of phenol. Explain how these conditions show phenol to be more reactive than benzene. conditions explanation  Suggest why phenol is more reactive than benzene. Complete the mechanism for the nitration of phenol to form 2-nitrophenol. You should assume that the mechanism is the same as that for the nitration of benzene. ● Include all relevant charges and curly arrows to show the movement of electron pairs. ● Draw the structure of the intermediate. ● You do not need to draw the products. phenol intermediate products OH +NO2 Name the isomer of 2‑nitrophenol which is also a major product of this reaction.
9701_s18_qp_42
THEORY
2018
Paper 4, Variant 2
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Questions Discovered
83