El mass spectra of some drug molecules

El mass spectrum of limonene produced by retro Diels-Alder fragmentation. 

Drug molecules in which homolytic a-cleavage dominates the spectrum 

A similar type of fragmentation dominates the spectrum of other local anaesthetics such as prilocaine and procaine and sympathomimetics such as ephedrine, salbutamol and terbutaline and P-adrenergic blockers such as propranolol and oxyprenolol. 

The isotopes of all the other elements commonly found in drug molecules are much less abundant, although because of the number of carbon atoms in large 

Answers The mass spectra of all these molecules are dominated by homolytic a-cleavage next to the nitrogen atom in their side chains, (i) m/z 86 (ii) m/z 72 (iii) m/z 58 (iv) m/z 98. 

---