Quinolines electrochemical reductive

Infrared spectral studies have been made for a large number of octahedral metal-carbonyl systems of the types LM(CO)5 (L = pyridine and quinoline), L2M(CO)4 [L2 = ethylene diamine, (pyridine)2, and bipyridyl], [LM(CO)4]2 (L = dimethylarsine or dimethylphosphine M = Cr, Mo, and W), and [LFe(CO)3]2 (L = SMe, PMe2) before and after electrochemical reduction. The force constants for the carbonyl groups... 

Electron-attracting substituents facilitate electrochemical reduction. The reduction potentials for the polarographic reduction of quinoline and isoquinoline derivatives are much less negative than those for the pyridine analogues. Diazines are reduced electrochemically stepwise, usually as far as tetrahydro derivatives (70AHC(12)262). 

A first order dependence of the rate on the quinoline concentration Is observed, as compared with a second order dependence In a similar benzene In water mlcroemulslon. The nature of the oil also has a significant effect on the electrochemical reduction of Cu(II), the half-wave potentlal(E2/2) being about 0.9 volts more negative In the mineral oil mlcroemulslon. The addition of quinoline causes a positive shift In Ej /2 which Is a-scrlbed to the formation of a four coordinate Cu(I) complex. Although aqueous Inorganic Ions are normally repelled by a microdroplet Interface of the same charge, It Is found that cadmlum(II) Ion Is bound to a droplet stabilized by the cationic surfactant cetyltrlmethyl ammonium bromide. This behavior Is Interpreted as arising from the formation of anionic species such as CdBr In the Stern layer. 

The electrochemical reduction of CO2 catalyzed by ]Ru(bpy)2(qu)(CO)] (qu = quinoline) in the presence of (CH3)4N or CH3I in dry CH3CN produces CH3COCH3, CH3COCH2CO2 and HCO2 . The fotur-carbon component CH3C0CH2C02 is derived from acetone via a carboxylation reaction by [Ru(bpy)2-(qu)(CO)] " [146e,f]. 

In the current study cyclic voltammetry was performed on two quinoline-type anticancer drugs, Dup 785 6 and camptothecin 9 to ascertain whether they possess the requisite characteristics of ET agents. Emphasis is placed on reduction potentials obtained for the quinolinium (iminium) forms. Several model compounds were examined in order to determine the effect of substituents. Reduction potentials were obtained in both protic and aprotic solvents to simulate environments which may pertain at the active site. In addition, Epp/2 and A Ep values were calculated (Table 2). The relationship of electrochemical characteristics to drug activity is addressed. 

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