70035-91-5Relevant academic research and scientific papers
ELECTROCHEMICAL REDUCTION OF 2,2'-DINITRODIPHENYLMETHANE AND 2,2'-DINITROBENZOPHENONE AT MERCURY ELECTRODES
Voigtlaender, Rolf,Hlavaty, Jaromir,Volke, Jiri,Bakos, Viktor
, p. 364 - 378 (2007/10/02)
The last two compounds in a 5-membered series of aromatic dinitrocompounds are reduced in a completely different manner at mercury electrodes. 2,2'-Dinitrodiphenylmethane (I) - in which a conjugation of both symmetrical moieties is ruled out - is electrolytically reduced in an eight-electron step to a bishydroxylamine this being most stable between pH 4.5 and 5.0.In processing the catholyte increase in concentration of this product leads to its intermolecular disproportionation, resulting in the formation of dibenzo-1,2-diazepine 5-oxide (IV) and2,2'-diaminodiphenylmethane (III). 2,2'-Dinitrobenzophenone (II) reduces at more positive potentials.Its preparative electrolysis in acetonitrile (with 0.1M-N(n-C4H9)4PF6 as supporting electrolyte) the application of which was made necesarry by the low solubility of II in ethanol, proceeds in an anomalous way.In the most positive cathodic wave a radical anion results, the following cathodic wave corresponds to a 6-electron reduction of one nitro group to an amino group while the other nitro group splits off as the anion NO2(-) (this later giving an anodic wave).Its formation has been proved by standard addition in polarography and by a qualitative analytical test.The product which results through this electrode process and a follow-up chemical reaction is acridone.This is turn, reduces in the third, most negative 4-electron wave to dihydroacridine.The comparison of all substances studied in this series reveals that their reducibility decreases with respect to the link X, viz. in the sequence CO > O > S and CH2 > NH.The electrolytical reduction on mercury cathodes occurs in a similar manner with analogues where X=O, S or CH2.Here, the main intermediate is the bis-hydroxylamine the stability of which predetermines the structure of final products.The other group comprises the substances with X=CO and NH.Here the main intermediate is the 2-nitro-2'-amino-diphenyl-X which is formed in a 6-electron process taking place at one of the nitro groups.The follow-up cyclization reaction leading to seven-membered heterocyclic rings located between two benzene nuclei only occurs with analogues of the type X=CH2, O and S.A partial reduction of dinitro compounds of this series has been observed with the analogue containing the NH link although that with X=CO has generally good preconditions for this mechanism.
