合成路线1

This compound has been obtained by three related ways: 1. The lithiation of N-(1-ethylpyrrolidin-2(S)-ylmethyl)-2,3-dimethoxybenzamide (I) with n-BuLi gives the dilithium salt (II), which by reaction with tosyl azide yields 6-azido-N-(1-ethylpyrrolidin-2(S)-ylmethyl)-2,3-dimethoxybenzamide (III). The reduction of the azido group of (III) with SnCl2 yields the corresponding amino derivative (IV), which is finally brominated with Br2 to afford the target compound. 2. The reaction of N-(3,4-dimethoxyphenyl)carbamic acid tert-butyl ester (V) with n-BuLi and CO2 gives 6-(tert-butoxycarbonyl)-2,3-dimethoxybenzoic acid (VI), which is condensed with (S)-1-ethylpyrrolidin-2-ylmethylamine (VII) by means of SOCl2, yielding the already reported 2-aminobenzamide (IV). 3. The intermediate carboxylic acid (VI) can also be first brominated with Br2 to give 5-bromo-6-(tert-butoxycarbonyl)-2,3-dimethoxybenzoic acid (VIII), which is finally condensed with (S)-1-ethylpyrrolidin-2-ylmethylamine (VII) by means of SOCl2, yielding the target compound.