Acridine regioselective reduction

Several homogeneous systems have been reported to catalyze the hydrogenation of polynuclear N-heterocycles efficiently the regioselective reduction of the N-containing ring in quinoline, isoquinoline, indole, benzoquinolines, acridine and other related molecules can be achieved with relative ease and under moderate conditions of temperature and pressure. A number of metals are known to be active (Cr, Mo, W, Mn, Fe, Ru, Os, Co, Rh, Ir) but most of the published work has concentrated on ruthenium and rhodium precursors [95-100] as shown in Table 3.3. 

The reduction of acridine by water gas (CO + H2O), synthesis gas (CO H2) or hydrogen alone is catalysed by transition metal carbonyls. The reaction is highly regioselective, only the heterocyclic ring being hydrogenated (R.H. Fish. A.D. Thormodsen and 6.A. Cremer, J. Amer. chem. Soc., 1982, 104. 5234). A similar... 

---