The cyclization of 2-acetonylcyclohexanone (I) with alanine ethyl ester (II) by means of sodium acetate in refluxing acetic acid gives ethyl 2-(4,5,6,7-tetrahydro-2-methylindol-1-yl)propionate (III), which is reduced with LiAlH4 in ether and acetylated with acetic anhydride in pyridine yielding 1-(1-acetoxy-2-propyl)-2-methyl-4,5,6,7-tetrahydroindole (IV). The benzoylation of (IV) with benzoic anhydride (V) and HI at 145 C affords 1-(1-acetoxy-2-propyl)-3-benzoyl-2-methyl-4,5,6,7-tetrahydroindole (VI), which is aromatized by treatment with 2,3-dichloro-5,6-dicyanobenzoquinone (VII) in refluxing dioxane to afford 1-(1-acetoxy-2-propyl)-3-benzoyl-2-methylindole (VIII) The hydrolysis of (VIII) with NaOH in methanol water gives 1-(1-hydroxy-2-propyl)-3-benzoyl-2-methylindole (IX), which is finally alkylated with ethyl bromide by means of NaH in dimethoxyethane.

The cyclization of 2-acetonylcyclohexanone (I) with alanine ethyl ester (II) by means of sodium acetate in refluxing acetic acid gives ethyl 2-(4,5,6,7-tetrahydro-2-methylindol-1-yl)propionate (III), which is reduced with LiAlH4 in ether and acetylated with acetic anhydride in pyridine yielding 1-(1-acetoxy-2-propyl)-2-methyl-4,5,6,7-tetrahydroindole (IV). The benzoylation of (IV) with benzoic anhydride (V) and HI at 145 C affords 1-(1-acetoxy-2-propyl)-3-benzoyl-2-methyl-4,5,6,7-tetrahydroindole (VI), which is aromatized by treatment with 2,3-dichloro-5,6-dicyanobenzoquinone (VII) in refluxing dioxane to afford 1-(1-acetoxy-2-propyl)-3-benzoyl-2-methylindole (VIII) The hydrolysis of (VIII) with NaOH in methanol water gives 1-(1-hydroxy-2-propyl)-3-benzoyl-2-methylindole (IX), which is finally alkylated with ethyl bromide by means of NaH in dimethoxyethane.