The rearrangement of aromatic nitro compounds. Part 3. The mechanism of rearrangement of nitrated hydrocarbons in trifluoromethanesulphonic acid
作者:John V. Bullen、John H. Ridd、Omaima Sabek
DOI:10.1039/p29900001681
日期:——
1,3-Dialkyl-2-nitrobenzenes (C6H3R2NO2; R = Me, Et, and Pri) rearrange in trifluoromethane-sulphonic acid to the corresponding 4-nitro derivatives; with R = Et, this reaction is accompanied by dehydration to 7-ethyl-3-methylanthranil. The reaction rate increases markedly with the size of the alkyl group; with R = Me, the reaction was studied at 110 °C but, with R = Pri, temperatures of 36–54 °C were
1,3-二烷基-2-硝基苯(C 6 H 3 R 2 NO 2; R = Me,Et和Pr i)在三氟甲烷磺酸中重排为相应的4-硝基衍生物;当R = Et时,该反应伴随脱水成7-乙基-3-甲基蒽。反应速度随着烷基的大小而显着增加。在R = Me的情况下,在110°C下研究了反应,但是在R = Pr i的情况下,使用了36–54°C的温度。R = Me的研究表明反应是一阶反应,速率系数(k 1)随着溶液的酸度[d(log k 1)/ d(– H 0)迅速增加。)] = 1.45,随着酸度降低至0.49。用2 H和15 N进行的双标记实验表明该反应是分子内的。在这些条件下,1,2,4-三甲基-3-硝基苯也重排,主要得到5-硝基异构体。根据硝基的直接1,3-转移来讨论以上结果。