The reaction of 4-methoxybenzylmagnesium bromide (I) with 1,3,4-trimethylpyridinium bromide (II) in ether, followed by a Diels-Alder condensation with ethyl acrylate (III) gives ethyl 3-(4-methoxybenzyl)-2,4,8-trimethyl-2-azabicyclo[2.2.2]oct-7-ene-6-carboxylate (IV), which is cyclized by means of HF yielding ethyl 1,2,3,4,4a,5,10,10a-octahydro-7-methoxy-1,4a,5-trimethyl-2,5-methanobenzo[g]quinoline-3-carboxylate (V). Acylation of (V) with hexanoyl chloride (VI) and butyllithium-diisopropylamine in THF affords the corresponding acyl derivative (VII), which is submitted to a reductive ring opening with formic acid in refluxing mesytilene giving 1,2,3,4,5,6-hexahydro-8-methoxy-3,6,11-trimethyl-11-(3-oxo-1-octyl)-2,6-methano-3-benzazocine (VIII). Finally, this compound is demethylated with 48% HBr and treated with methanesulfonic acid.

The reaction of 4-methoxybenzylmagnesium bromide (I) with 1,3,4-trimethylpyridinium bromide (II) in ether, followed by a Diels-Alder condensation with ethyl acrylate (III) gives ethyl 3-(4-methoxybenzyl)-2,4,8-trimethyl-2-azabicyclo[2.2.2]oct-7-ene-6-carboxylate (IV), which is cyclized by means of HF yielding ethyl 1,2,3,4,4a,5,10,10a-octahydro-7-methoxy-1,4a,5-trimethyl-2,5-methanobenzo[g]quinoline-3-carboxylate (V). Acylation of (V) with hexanoyl chloride (VI) and butyllithium-diisopropylamine in THF affords the corresponding acyl derivative (VII), which is submitted to a reductive ring opening with formic acid in refluxing mesytilene giving 1,2,3,4,5,6-hexahydro-8-methoxy-3,6,11-trimethyl-11-(3-oxo-1-octyl)-2,6-methano-3-benzazocine (VIII). Finally, this compound is demethylated with 48% HBr and treated with methanesulfonic acid.

The reaction of 4-methoxybenzylmagnesium bromide (I) with 1,3,4-trimethylpyridinium bromide (II) in ether, followed by a Diels-Alder condensation with ethyl acrylate (III) gives ethyl 3-(4-methoxybenzyl)-2,4,8-trimethyl-2-azabicyclo[2.2.2]oct-7-ene-6-carboxylate (IV), which is cyclized by means of HF yielding ethyl 1,2,3,4,4a,5,10,10a-octahydro-7-methoxy-1,4a,5-trimethyl-2,5-methanobenzo[g]quinoline-3-carboxylate (V). Acylation of (V) with hexanoyl chloride (VI) and butyllithium-diisopropylamine in THF affords the corresponding acyl derivative (VII), which is submitted to a reductive ring opening with formic acid in refluxing mesytilene giving 1,2,3,4,5,6-hexahydro-8-methoxy-3,6,11-trimethyl-11-(3-oxo-1-octyl)-2,6-methano-3-benzazocine (VIII). Finally, this compound is demethylated with 48% HBr and treated with methanesulfonic acid.