Quinolizinium-l-olates

The conversion of 1-hydroxyquinolizinium bromide (187 R = R = H, X = Br) into three quinolizinium-l-olate derivatives (186) has been achieved as follows (i) Treatment with aqueous sodium carbonate gives the hydrated betaine (186 R = R = H) as a yellow solid (ii) brief reaction with hot dilute nitric acid gives red needles of the 4-bromo-2-nitro derivative (186 R = NO2, R = Br) and (iii) prolonged reaction with hot dilute nitric acid gives the dinitro derivative (186 R = R = NO2). 1-Hydroxyquinolizinium nitrate (187 R = R = H, X = NO2) and dilute nitric acid give the 2-nitro derivative(186 R = NO2, R = H). ° ° Betaine 186(R = Me, R = H) has been detected in aqueous solutions of l-hydroxy-2-methylquinolizinium bromide (187 R = Me, R = H). °  

Little is known about the chemistry of this class of mesomeric betaines. Catalytic reduction of the 2-nitro betaine (186 R = NO2, = H) gives 

2-hydroxy-3-aminoquinolizinium bromide. Compound 186 (R = R = H) and benzyl bromide give 1-benzyloxyquinolizinium bromide (188). 

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