115879-39-5Relevant academic research and scientific papers
Polarography and Mechanisms of Electrochemical Reductions of Partially Saturated 5,8-Methanobenzoxazines
Richter, H. P.,Stajer, G.,Pflegel, P.,Bernath, G.
, p. 666 - 670 (2007/10/02)
In neutral and alkaline electrolytes, the title compounds 1-9 have been reduced in a 2e step at the azomethine bond by dc polarography at the dropping mercury electrode.In acidic electrolytes, the wave height increases and reaches the 4e level in the case of 1-7.This is caused by the ring-chain-tautomerism of the 2e products (condensed-skeleton 2-aryl-substituted tetrahydro-1,3-oxazine derivatives) to aldimine derivatives, which are reduced in a further 2e step.The mechanism was confirmed by controlled potential electrolysis at pH=1.5, in the course of which hydrolysi s of the aldimine to the aldehyde and aminoalcohol component was detected as a competitive reaction.Structural influences on the polarographic reduction are recognizable from the different half-wave potentials of the individual derivatives.Substances with diexo coupling of the norbornane (or norbornene) and the 1,3-oxazine ring are reduced more easily than the corresponding diendo derivatives (ΔE1/2 = 10-50 mV) and oxazines with 5,6-condensation more easily than the isomeric substances with 4,5-condensation (ΔE1/2 = 100 mV), whereas the insertion of a C=C double bond into ring A of the norbornane moiety has no influence on the reducibility.Further, the reduction is facilitated by chlorine substitution in 3- or 4-position on the 2-phenyl substituent of the oxazine ring (up to ΔE1/2 = 120 mV).
