Res. Chem. Intermed.
, Vol. 32, No. 9, pp. 827–836 (2006)
Also available online - www.brill.nl/rci
-induced β-elimination reactions with
1-(2-Xethyl)-4-nitrobenzene substrates in solvent mixture
CN and H
O/DMSO: reactivity and mechanism
, ROBERTO MELIS and LAURA OTTAVI
Università degli Studi di Perugia, Dipartimento di Chimica, sez. Chimica Organica,
via Elce di Sotto 8, I-06123 Perugia, Italy
Received 8 May 2006; accepted 3 August 2006
Abstract—The behaviour of 1-(2-bromoethyl) 4-nitrobenzene (1), N,N,N -triethyl-2-(4-nitrophe-
nyl)ethanaminium bromide (2)andN,N -diethyl-N-[2-(4-nitrophenyl)ethyl]octan-1-aminium bromide
-induced elimination reactions with formation of 1-nitro-4-vinylbenzene in mixtures
O has been investigated. With all three substrates an increase in dipolar
aprotic solvent content implies a limited increase of the second-order rate constant k
and then an exponential increase is observed. The variation of activation parameters H
measured in DMSO/H
O mixtures, is parallel for 1 and 2. This similar behaviour of 1 and 2 with
respect to variation in solvent composition is evidence that it is not possible to use this technique of
solvent effect for the mechanistic diagnosis of elimination reactions.
Keywords: 1-(2-Bromoethyl) 4-nitrobenzene; N,N,N -triethyl-2-(4-nitrophenyl)ethanaminium bro-
mide; N,N -diethyl-N-[2-(4-nitrophenyl)ethyl]octan 1-aminium bromide; OH
dipolar aprotic solvent.
The solvent effect is important owing to its inﬂuence to both reactivity and
mechanism of chemical reactions [1– 11]. The use of mixtures of H
aprotic solvents is of interest, as the solubility of organic compounds is greatly
enhanced and the related chemical reactions can be strongly accelerated.
Elimination reactions are a class of organic reactions of interest [12 –17] for the
various possible mechanisms that can operate and for the related importance in syn-
thetic organic chemistry; also, they are involved in several biological transforma-
tions  and the study in a mixture of H
O/dipolar aprotic solvent can help in
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