The selective methylation of 5,6,7,8-tetrahydro-5,8-ethanonaphthalene-1,4-diol (I) with dimethylsulfate in a two phase system gives 4-methoxy-5,6,7,8-tetrahydro-5,8-ethano-1-naphthol (II), which is condensed with epichlorohydrin (III) by means of piperidine at 100 C yielding 1-methoxy-4-(2,3-epoxypropoxy)-5,6,7,8-tetrahydro-5,8-ethanonaphthalene (IV). The reaction of (IV) with tert-butylamine (V) at 100 C affords 1-methoxy-4-[3-(tert-butylamino)-2-hydroxypropoxy]-5,6,7,8-tetrahydro-5,8-ethanonaphthalene (VI), which is finally demethylated by treatment with pyridine hydrochloride at 160 C
The selective hydrolysis of 1,4-diacetoxy-5,6,7,8-tetrahydro-5,8-ethanonaphthalene (VII) with diethylamine in methanol gives 4-acetoxy-5,6,7,8-tetrahydro-5,8-ethano-1-naphthol (VIII), which is condensed with epichlorohydrin (III) by means of piperidine at 90 C to afford 1-acetoxy-4-(2,3-epoxypropoxy)-5,6,7,8-tetrahydro-5,8-ethanonaphthalene (VII). The reaction of (IX) with tert-butylamine (V) in refluxing toluene gives 1-acetoxy-4-[3-(tert-butylamino)-2-hydroxypropoxy]-5,6,7,8-tetrahydro-5,8-ethanonaphthalene (X), which is finally hydrolyzed with dry HCl in refluxing methanol