Structure, Preparation, and Detection of Iminium Salts

Structure, Preparation, and Detection of Iminium Salts A. Structure oe Iminium Salts The positively charged carbon-nitrogen double bond 

Iminium salts can be made in a number of ways such as protonation of enamines (7), alkylation of aldimines and ketimines (5,9), cleavage of a covalent bond in a 

Iminium salts are readily available from C protonation of the corresponding enamines (7). Experimentally the procedure is very simple The enamine dissolved in ether or some other solvent is treated with an appropriate acid such as anhydrous hydrogen chloride or 70% perchloric acid. The iminium salt usually separates and is then collected. Protonation at low temperatures 

Compound Time at room temperature Diazomethane per cent protonation At C At N UAIH4 per cent protonation At C At N  

In a similar manner N-(2-ethyl)butylidenepiperidinium hexachlorostannate gives mostly diethyl ketone and only a little of 2-ethylbutanal when a fresh solution is ozonized. If allowed to stand for a period of time, the only product obtained by ozonolysis is 2-ethylbutanal 16). 

---