A-Level CIE Chemistry 7.5 Amines (A Level only): Astronomers using modern telesco

Question

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 aminothanoic acid, H₂NCH₂CO₂H, are present.

One molecule that has been found in the dust clouds is hydroxyethanal, HOCH₂CHO.

(a) Hydroxyethanal contains two functional groups.

(i) Name, as fully as you can, each of the functional groups present in hydroxyethanal.

1 -----------------------------------------------------  
2 -----------------------------------------------------

(ii) 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 -----------------------------------------------------

(b) Give the skeletal formulae of the organic compounds formed when hydroxyethanal is reacted separately with the following.

(i) NaBH₄

(ii) Cr₂O₇²⁻/H⁺ under reflux conditions

(c) In a school or college laboratory, it is possible to convert a sample of hydroxyethanal into aminothenoic acid in a three-step process.

HOCH₂CHO  step 1 × 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.

(i) In the boxes below, draw the structural formulae of your suggested intermediates X and Y.

-----------------------------------------------------  
                        X                       Y
-----------------------------------------------------

(ii) State the reagents for each of the three steps you have chosen.

step 1 -----------------------------------------------------  
step 2 -----------------------------------------------------  
step 3 -----------------------------------------------------

Astronomers using modern telescopes of various types have found many molecules in the dust clouds in space - CIE - A-Level Chemistry - Question 5 - 2011 - Paper 2

Worked Solution & Example Answer:Astronomers using modern telescopes of various types have found many molecules in the dust clouds in space - CIE - A-Level Chemistry - Question 5 - 2011 - Paper 2

a) (i) Name, as fully as you can, each of the functional groups present in hydroxyethanal.

a) (ii) For each functional group, identify a reagent that will react with this group and not react with the other functional group present.

b) Give the skeletal formulae of the organic compounds formed when hydroxyethanal is reacted separately with the following.

c) (i) In the boxes below, draw the structural formulae of your suggested intermediates X and Y.

c) (ii) State the reagents for each of the three steps you have chosen.

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