The reduction of 5-nitro-2-methylisoquinolinium p-toluenesulfonate (I) with H2 over PtO2 in acetic acid H2SO4 gives 5-amino-2-methyldecahydroisoquinoline (II), which is acetylated with acetic anhydride in DMF and submitted to fractionated crystallization to give cis-5,9,10-H-5-acetamido-2-methyldecahydroisoquinoline (III). Hydrolysis of (III) with H2SO4 in refluxing water yields cis-5,9,10-H-5-amino-2-methylisoquinoline (IV), which is finally acylated with 3,4,5-trimethoxybenzoyl chloride (V) by means of KHCO3 in benzene.
The reduction of 5-nitro-2-methylisoquinolinium p-toluenesulfonate (I) with H2 over PtO2 in acetic acid H2SO4 gives 5-amino-2-methyldecahydroisoquinoline (II), which is acetylated with acetic anhydride in DMF and submitted to fractionated crystallization to give trans-5,9,10-H-5-acetamido-2-methyldecahydroisoquinoline (III). Hydrolysis of (III) with H2SO4 in refluxing water yields trans-5,9,10-H-5-amino-2-methylisoquinoline (IV), which is finally acylated with 3,4,5-trimethoxybenzoyl chloride (V) by means of KHCO3 in benzene.