Acridine, basicity hydrolysis

Wardani and Lhomme (93TL6411) used a different pathway for the construction of the pyrrole ring. Base-catalyzed alkylation of N-acetyl-N -tosylproflavine 60 with bromoacetaldehyde diethyl acetal, followed by deprotection of the acetal function with concomitant ring closure and deacylation in acidic media yielded 9-amino-3-tosylpyrrolo[2,3-c]acridine 301. Detosylation was achieved by basic hydrolysis to give 9-aminopyr-rolo[2,3-c]acridine 302 (Scheme 55). 

In the hydrolysis of acridine antimalarials, the role of the protonated species of the substrate appeared to be important even in aqueous solution buffered at pH 7.3, i.e., under conditions of physiological interest.Moreover, out of the three possible modes of reaction mathematically possible (H3O+-HB, HgO-f BH+, and OH -f BH2+, where B is the basic substrate) the one not involving the protonated substrate can be ruled out on structural grounds. 

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