Novel Effect of Thiourea/Urea Additives on the Nucleophilic Aromatic Substitution of 2,4-Dimethoxynitrobenzene

摘要

The nucleophilic aromatic substitution(S_NAr)reaction is a convenient method to synthesize polysubstituted aromatics without the use of any transition metal catalyst.The conditions for the regioselective S_NAr reaction in 2,4-dihaloaromatics have been reported.Recently,we reported that the S_NAr reaction of 2,4-dimethoxynitrobenzene(1)with a bulky nucleophile,sodium tert-butoxide afforded the desired product 2(2-t-butoxy-4-methoxy nitrobenzene)in an excellent yield with exclusive ortho-selectivity under the optimized condition and the formation of the detectable byproduct 3(2,4-dimethoxy-N-(5-methoxy-2-nitrophenyl)aniline)was elucidated using X-ray crystallography.