Protoberberines from Reissert-Compounds, IV. A Novel Synthesis of (+/-)-Alamaridine and (+/-)-epi-Alamaridine

Article abstract of DOI:10.1007/BF00811089

A novel synthesis of 8-methylisoquino<2,1-b><2,7>naphthyridinium salts 7 is reported using the intramolecular cyclization of the 1-substituted isoquinolines 5 as the key step, which in turn are obtained by alkylation of the Reissert compound 1.The salts 7 can be reduced by NaBH4 yielding the 8α- and 8β-methylstereomers (+/-)-alamaridine and (+/-)-epi-alamaridine 9c and 11c, respectively. - Keywords.Reissert compounds; Intramolecular cyclization; 8-Methylisoquino<2,1-b><2,7>naphthyridinium chlorides; (+/-)-Alamaridine; (+/-)-epi-Alamaridine.