1706-61-2Relevant articles and documents
Electrophilic aromatic substitution. Part 24. The nitration of isopropylbenzene, 2- and 4-isopropyltoluene, 1-chloro-4-isopropylbenzene, 4-isopropylanisole, and 2-bromotoluene: Nitrodeisopropylation
Manglik, Ajay K.,Moodie, Roy B.,Schofield, Kenneth,Tobin, Geoffrey D.,Coombes, Robert G.,Hadjigeorgiou, Panicos
, p. 1606 - 1616 (2007/10/02)
The kinetics and products of nitration in aqueous sulphuric acid of the title compounds have been studied. 4-Isopropyl-phenol and -anisole are nitrated at or near the encounter rate. In 65-79% H2SO4 2-isopropyltoluene suffers ca. 25% ipso-attack; the only fate of W iPri (ipso-Wheland intermediate) is nitrodeisopropylation. From 4-isopropyltoluene WiPri is also nitrodeisopropylated, but some 1,2-nitro-migration may occur. From the same compound WiMe may be captured by water, rearrange, or give 4-methylacetophenone; a mechanism is proposed for the formation of the last compound. Nitrodeisopropylation occurs without the assistance of water. With 4-isopropylanisole, demethoxylation and nitrodeisopropylation are consequences of the formation of WiPri. The results are consistent with increasing attack at C-4 with increasing acidity, loss of isopropyl without assistance from water, and decomposition of the unobserved intermediate, 4-isopropyl-4-nitrocyclohexa-2,5-dienone, by two processes. One, acid-catalysed process gives 4-nitrophenol and possibly 4-isopropyl-2-nitrophenol. The other, probably radical, process gives 4-isopropyl-2-nitrophenol. In contrast to 4-bromotoluene, 2-bromotoluene is not nitrodebrominated.
