21. Organic synthesis
A section of Chemistry, 9701
Listing 10 of 83 questions
Astronomers using modern telescopes of various types have found many molecules in the dust clouds in space. Many of these molecules are those of organic compounds and astronomers constantly look for evidence that amino acids such as aminoethanoic acid, H2NCH2CO2H, are present. One molecule that has been found in the dust clouds is hydroxyethanal, HOCH2CHO. Hydroxyethanal contains two functional groups. Name, as fully as you can, each of the functional groups present in hydroxyethanal. For each functional group, identify a reagent that will react with this group and not react with the other functional group present. In each case, describe what would be observed when this reaction is carried out. functional group 1 reagent observation functional group 2 reagent observation Give the skeletal formulae of the organic compounds formed when hydroxyethanal is reacted separately with the following. NaBH4 Cr2O7 2–/H+ under reflux conditions In a school or college laboratory, it is possible to convert a sample of hydroxyethanal into aminoethanoic acid in a three-step process. HOCH2CHO step 1 X step 2 Y step 3 H2NCH2CO2H By considering the possible reactions of the functional groups present in hydroxyethanal, you are to deduce a possible route for this conversion. In the boxes below, draw the structural formulae of your suggested intermediates X and Y. X Y State the reagents for each of the three steps you have chosen. step 1 step 2 step 3
9701_w11_qp_21
THEORY
2011
Paper 2, Variant 1
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Astronomers using modern telescopes of various types have found many molecules in the dust clouds in space. Many of these molecules are those of organic compounds and astronomers constantly look for evidence that amino acids such as aminoethanoic acid, H2NCH2CO2H, are present. One molecule that has been found in the dust clouds is hydroxyethanal, HOCH2CHO. Hydroxyethanal contains two functional groups. Name, as fully as you can, each of the functional groups present in hydroxyethanal. For each functional group, identify a reagent that will react with this group and not react with the other functional group present. In each case, describe what would be observed when this reaction is carried out. functional group 1 reagent observation functional group 2 reagent observation Give the skeletal formulae of the organic compounds formed when hydroxyethanal is reacted separately with the following. NaBH4 Cr2O7 2–/H+ under reflux conditions In a school or college laboratory, it is possible to convert a sample of hydroxyethanal into aminoethanoic acid in a three-step process. HOCH2CHO step 1 X step 2 Y step 3 H2NCH2CO2H By considering the possible reactions of the functional groups present in hydroxyethanal, you are to deduce a possible route for this conversion. In the boxes below, draw the structural formulae of your suggested intermediates X and Y. X Y State the reagents for each of the three steps you have chosen. step 1 step 2 step 3
9701_w11_qp_22
THEORY
2011
Paper 2, Variant 2
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Sunset Yellow is a yellow colouring agent used in food and drinks, which can be made by the following route. In step 3 of this synthesis, a phenol-like compound, S, reacts with intermediate T made from amine R. Assume that the –SO3 – Na+ group does not react. SO3 – Na+ SO3 – Na+ O2N step 1 step 2 + Sunset Yellow step 3 NaOHR (C6H6NSO3Na) T S Q OH Na+ –O3S N N Suggest structures for compounds R, S and T and draw them in the boxes above. Suggest reagents and conditions for step 1, step 2. What type of organic salt is formed in step 2? Compound W has the following structure. NH2 H2N O How many σ and π bonds are present in a molecule of W? σ bonds π bonds The products of the reactions of W with cold HCl and with CH3CH2Br are soluble in water but not in organic solvents. Complete the table for these reactions of W. reagent structure of product (molecular formula given) type of reaction HCl (C4H9N2OCl ) CH3CH2Br (C6H13N2BrO)
9701_w15_qp_41
THEORY
2015
Paper 4, Variant 1
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Sunset Yellow is a yellow colouring agent used in food and drinks, which can be made by the following route. In step 3 of this synthesis, a phenol-like compound, S, reacts with intermediate T made from amine R. Assume that the –SO3 – Na+ group does not react. SO3 – Na+ SO3 – Na+ O2N step 1 step 2 + Sunset Yellow step 3 NaOHR (C6H6NSO3Na) T S Q OH Na+ –O3S N N Suggest structures for compounds R, S and T and draw them in the boxes above. Suggest reagents and conditions for step 1, step 2. What type of organic salt is formed in step 2? Compound W has the following structure. NH2 H2N O How many σ and π bonds are present in a molecule of W? σ bonds π bonds The products of the reactions of W with cold HCl and with CH3CH2Br are soluble in water but not in organic solvents. Complete the table for these reactions of W. reagent structure of product (molecular formula given) type of reaction HCl (C4H9N2OCl ) CH3CH2Br (C6H13N2BrO)
9701_w15_qp_42
THEORY
2015
Paper 4, Variant 2
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4-nitrophenol can be converted into a range of useful organic products. OH O2N 4-nitrophenol 4-nitrophenol can react with three different reagents. Complete the table by: • drawing the structures of the organic products formed, • identifying the non-organic products formed. reagent organic product structure identity of non-organic product NaBr2CH3COCl 4-nitrophenol can also be used in the synthesis of the dye Mordant Brown by the following route. In step 2 of this synthesis, 4-nitrophenol reacts with intermediate F made from amine E. Assume that the –SO3 – Na+ group does not react. + OH NO2 E (C6H8N3SO3Na) F step 1 step 2 OH NO2 N N SO3 – Na+ H2N NH2 Mordant Brown Suggest structures for compounds E and F and draw them in the boxes above. Suggest reagents and conditions for step 1, step 2.
9701_w15_qp_43
THEORY
2015
Paper 4, Variant 3
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Ibuprofen and paracetamol are pain-relief drugs. ibuprofen paracetamol O OH N H O OH Ibuprofen and paracetamol both contain the aryl functional group. Name the other functional groups present in each molecule. ibuprofen paracetamol Ibuprofen contains a chiral centre and shows stereoisomerism. State what is meant by the term chiral centre. Draw the two stereoisomers of ibuprofen. C C Draw the structures of the organic products when ibuprofen and paracetamol react separately with LiAl H4. product with ibuprofen product with paracetamol A student carried out some reactions with solutions of ibuprofen and paracetamol using reagents D and E and the following results were obtained. ( means a reaction took place.) reagent ibuprofen paracetamol D   E   Suggest a possible identity for each reagent D and E. D E Give the structure of the organic product formed when reagent D reacted with ibuprofen. product with ibuprofen Give the structure of the organic product formed when reagent E reacted with paracetamol. product with paracetamol One of the steps in the manufacture of ibuprofen is shown. X Y CH3COCl Al Cl 3 O Write an equation for the reaction between CH3COCl and Al Cl 3. Complete the mechanism for the conversion of X into Y. Include all necessary curly arrows, any relevant dipoles and charges. X Name the mechanism in .
9701_w16_qp_41
THEORY
2016
Paper 4, Variant 1
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Ibuprofen and paracetamol are pain-relief drugs. ibuprofen paracetamol O OH N H O OH Ibuprofen and paracetamol both contain the aryl functional group. Name the other functional groups present in each molecule. ibuprofen paracetamol Ibuprofen contains a chiral centre and shows stereoisomerism. State what is meant by the term chiral centre. Draw the two stereoisomers of ibuprofen. C C Draw the structures of the organic products when ibuprofen and paracetamol react separately with LiAl H4. product with ibuprofen product with paracetamol A student carried out some reactions with solutions of ibuprofen and paracetamol using reagents D and E and the following results were obtained. ( means a reaction took place.) reagent ibuprofen paracetamol D   E   Suggest a possible identity for each reagent D and E. D E Give the structure of the organic product formed when reagent D reacted with ibuprofen. product with ibuprofen Give the structure of the organic product formed when reagent E reacted with paracetamol. product with paracetamol One of the steps in the manufacture of ibuprofen is shown. X Y CH3COCl Al Cl 3 O Write an equation for the reaction between CH3COCl and Al Cl 3. Complete the mechanism for the conversion of X into Y. Include all necessary curly arrows, any relevant dipoles and charges. X Name the mechanism in .
9701_w16_qp_43
THEORY
2016
Paper 4, Variant 3
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Questions Discovered
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