Abstract: 3,4,5-trimethoxyaniline was synthesized from 3,4,5-trimethoxybenzioc acid. 3,4,5-trimethoxyaniline through chlorination of 3,4,5-trimethoxybenzioc acid, amidation of 3,4,5-trimethoxybenzoyl chloride and Hofmann rearrangement reaction of 3,4,5-trimethoxybenzamide. The structure of 3,4,5-trimethoxyaniline was determined by FT-IR and GC-MS spectra. The optimal reaction conditions of 3,4,5-trimethoxybenzoyl chloride was as follows: n(phosphorus trichloride):n(3,4,5-trimethoxybenzioc acid)=0.65:1, toluene as the solvent, v(toluene):n(3,4,5-trimethoxybenzioc acid)=0.6:1(L:mol), reaction temperature 80℃, reaction time 3 h. The optimal reaction conditions of (3,4,5-trimethoxybenzamide) was as follows: n(ammonia):n(3,4,5-trimethoxybenzoyl chloride)=4:1, reaction temperature-5-0℃, reaction time 30 min. The optimal reaction conditions of (3,4,5-trimethoxyaniline) was as follows: n(NaOH):n(3,4,5-trimethoxybenzamide)=9:1, n(Br₂):n(3,4,5-trimethoxybenzamide)=1.15:1, rearrangement reaction temperature 40℃, rearrangement reaction time 20 min, decarboxylation temperature 85℃, decarboxylation time 1 h, deionized water as the solvent. Yield of obtained product was 66.8%, m.p. 112.5-113.5℃, purity of obtained product was 99.0%.

Key words: 5-trimethoxybenzoic acid, Hofamnn rearrangement, 5-trimethoxyaniline