Aromatic nucleophilic substitution reactions of some 2-L-3-nitro-5-X-thiophenes with piperidine and aniline in methanol. Substituent constants for the thiophene system
The rate constants for the reactions of some 2-L-3-nitro-5-X-thiophenes 1–4 with aniline and of compounds (4) with piperidine in methanol have been measured at various temperatures. By using the data obtained in this work as well as previously available data sets, a series of optimized ‘thiophene’σT values has been calculated. The susceptibility constants ρ(L)of the various sets have been analysed
Catalysis in aromatic nucleophilic substitution. Part 7. Kinetics of the reactions of some 5-substituted 2-methoxy-3-nitrothiophenes with piperidine in benzene
The kinetics of the reactions of some 2-methoxy-3-nitro-5-X-thiophenes (Ia–g; X = H, CONH2, CO2Me, Ac, SO2Me, CN, or NO2) with piperidine and with n-butylamine in benzene have been measured in the range 20–40 °C. The reactions with piperidine are catalysed by piperidine, being third-order overall (second-order in amine). The electronic effects of the 5-substituent on the ‘catalytic’ constants are shown
一些2-甲氧基-3-硝基-5-X-噻吩(Ia–g; X = H,CONH 2,CO 2 Me,Ac,SO 2 Me,CN或NO 2)与哌啶反应的动力学并在20–40°C范围内测量了苯中的正丁胺。与哌啶的反应由哌啶催化,总体为三级(胺中为二级)。显示5-取代基对“催化”常数的电子效应与苯中碱催化的SB-GA机理最一致。