Hydroxylamine → 3-p-Methoxyphenyl-1-methyl-4-piperidone oxime

Participants

Reaction Steps

Cis-8-methoxy-2-methyl-6-phenyl-1,2,3,4,4a,10b-hexahydrobenzo[c][1,6]naphthyridine is obtained by addition of 3-amino-2-p-methoxyphenylpropionic acid ethyl ester to acrylic acid ethyl ester, reductive methylation of 2-p-methoxyphenyl-3,3'-iminodipropionic acid diethyl ester (M.P. of the hydrogen oxalate 152°) with formaldehyde to obtain 2-p-methoxymethyl-N-methyl-3,3'-iminodipropionic acid diethyl ester, reaction of the latter compound to obtain 3-carbethoxy-5-(p-methoxyphenyl)-1-methyl-4-piperidone (M.P. of the hydrochloride 180°-182°), which is converted by hydrolysis and subsequent decarboxylation into 3-p-methoxyphenyl-1-methyl-4-piperidone (M.P. of the hydrogen oxalate 137°-138°). The resulting piperidone is reacted with hydroxylamine to obtain 3-p-methoxyphenyl-1-methyl-4-piperidone oxime (M.P. 121°-122°), the oxime is hydrogenated with Raney nickel to obtain 4-amino-3-p-methoxyphenyl-1-methyl-piperidine (mixture of the two diastereoisomers), the amino compound is treated with benzoyl chloride, cis-4-benzoylamino-3-p-methoxyphenyl-1-methylpiperidine (M.P. 164°-165°) is isolated from the reaction mixture, and the latter amide is cyclized with phosphorus oxychloride to obtain the desired benzonaphthyridine.

Provenance & Evidence