Question

Question 1. i. There are over 60 distinct molecules with the formula C3H7NO. One of these is a tertiary amide. Give its line structure. [1 mark] ii. Give the line structures and full IUPAC names of two molecules with formula C3H7NO that are enantiomers of one another. Provide a full explanation of how you obtained the IUPAC names. [9 marks] iii. One of the least stable isomers of C3H7NO is shown below: Discuss the factors that contribute to the instability of this molecule, supporting your answer with appropriate diagrams illustrating all factors mentioned. (10 marks]

Answer 1

i) The molecule with formula C₃H₇NO which is a tertiary amide is dimethyl formamide. The structure of which is given below

ii)

The compound with molecular formula C₃H₇NO which exists as enantiomers is given below

N-n. •NH HBC с. Но JJ

The molecule on the right is a non-superimposable image of the molecule on the left.

IUPAC Nomenclature rules for this molecule

1) compound having a 4 membered rings are referred as "et" from the word "tetra"

2) compounds having nitrogen in four membered rings are called "azetidine"

Therefore these molecules are called 2-hydroxy azetidine

The enantiomer on the left is

(R)-2-hydroxy azetidine (R isomer)

while the one on the right is the S-isomer

(S)-2-hydroxy azetidine

iii)

The compound listed above comprises of a three membered ring containing a nitrogen and an oxygen. The internal angle in such a ring should be around 60^o (based on geometry) which is quite away from the tetrahedral angle of 109^o28’. This causes enormous amount of strains in these rings. Therefore molecules of these kinds undergo several ring opening reactions which does not happen with similar straight chain compounds.