Question

4. Propose a structure for a molecule whose mass spectrum shows a parent ion at m/z 100 with a base peak at m/z 43, an IR peak at 1720 cm' which gave the following 'H NMR spectrum. 33 N - PPM 5. Propose a structure for a molecule whose mass spectrum shows a parent ion at m/z 100 with a base peak at m/z 43, an IR peak at 1720 cm' which gave the following 'H NMR spectrum. doublet 2 septet triplet PPM 6. Propose a structure for a molecule whose mass spectrum shows a parent ion at m/z 88, IR peaks at 1740 and -1150 cm' and gives the following 'H NMR spectrum. - 3 PPM

Answer 1

Solution:

Compound is 3-hexanone.

CH3CH2-COCH2CH2CH3

Explanation:

>>>Base peak =43 is due to CH3-C $\equiv$ O+ (acyl cation).

>>>IR peak 1720 cm-1 suggest the saturated ketone.

>>> Five nonequivalent types of protons are presence,

CH3a-CH2b- CO-CH2c-CH2d-CH3e

1) Three triplets:

These peaks are due to a (CH3), e(CH3) and c (CH2)

2) One quartet: due to b (CH2)

3) One pentate : due to d(CH2)