17. Carbonyl compounds
A section of Chemistry, 9701
Listing 10 of 304 questions
Serotonin can be synthesised from the amino acid tryptophan in two steps. NH2 CO2H N H NH2 CO2H N H tryptophan serotonin HO NH2 N H HO In a buffer solution at pH 5.9, a sample of tryptophan does not move during electrophoresis. Draw the structures of the ions formed by tryptophan at pH 1.0 and pH 5.9. pH 1.0 pH 5.9 Tryptophan can combine with valine to form a dipeptide. Use the Data Booklet to draw the structure of this dipeptide. Complete the following table to show the structures of the products formed and the typeofreaction occurring when serotonin reacts with the four reagents in separate reactions. reagent structure of product type of reaction Na excess Br2excess CH3COCl excess H2 / Pt catalyst Serotonin is converted by enzymes in the liver to compound M. serotonin NH2 N H HO M OH N H HO enzymes O By reference to the Data Booklet, suggest how the infra-red spectrum of M would differ from that of serotonin. The proton NMR spectrum of M dissolved in CDCl 3 shows eight peaks due to the eight different types of proton present in the molecule. The proton NMR spectrum of M dissolved in D2O was recorded. Predict the number of peaks that would be seen in the proton NMR spectrum of M in D2O. Explain your answer. number of peaks explanation Compound M can be polymerised under certain conditions to form polymer N, shown. N H O O N Polymer N is biodegradable, unlike polyethene which is not. Explain why N is biodegradable.
9701_w17_qp_42
THEORY
2017
Paper 4, Variant 2
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Questions Discovered
304