G. Micheletti, C. Boga, L. Forlani
Feb 3, 2017
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Influential Citations
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Journal
European Journal of Organic Chemistry
Abstract
The azo coupling reaction between 4-nitrobenzenediazonium tetrafluoroborate and a series of benzene derivatives bearing as electron donating substituents at least one hydroxy or methoxy group has been carried out. Depending on the nucleophile and its relative ratio with the diazonium salt it was possible to obtain mono-, di-, and, only in the case of phloroglucinol, evidence of trisubstitution products. The reaction between 3,5-diaminoanisole- or 3,5-diaminophenol- derivatives and two equivalents of diazonium salt gave, in the first case, the product derived from a mono attack, and a diadduct in the second case; their X-ray diffraction analysis showed an highly symmetric structure for the latter. The different behavior of hydroxy- with respect to the methoxy-substituted compounds was particularly evident for phloroglucinol and 1,3,5-trimethoxybenzene and it may be rationalized on the basis of the different electronic effect of the substituents. The propensity to undergo H/D exchange reaction on the aromatic ring was investigated on a series of substrates and the comparison of the results obtained provided new insights on this kind of phenomenon and permitted a better explanation of the findings reported here, by introducing a new particular interaction which competes with the -complex formation between proton and phloroglucinol