69560-46-9Relevant articles and documents
Conversion of the Naturally Occurring Amide Alkaloids into O5 Benzophenanthridinium Alkaloids. A New Synthetic Sequence to Antitumour Benzophenanthridine Alkaloids
Ishii, Hisashi,Ishikawa, Tsutomu,Watanabe, Toshiko,Ichikawa, Yuh-Ichiro,Kawanabe, Eri
, p. 2283 - 2290 (2007/10/02)
Cyclisation of methyl integriamide (17a) and methyl isoarnottianamide (17b) by the Bischler-Napieralski reaction gave the naturally occurring O5 benzophenanthridine alkaloids, chelirubine (5a), and chelilutine (5b), respectively; this was extended to give a generally applicable, versatile synthesis of benzophenanthridine alkaloids from 2-aryl-3,4-dihydronaphthalen-1(2H)-ones (13).Treatment of the tetralones (13) with methylamine and titanium tetrachloride followed by sodium borohydride provided the cis-2-aryl-N-methyl-1,2,3,4-tetrahydro-1-naphthylamines (14) which were converted into the N-formyl derivatives (15) with freshly prepared chloral in good yields.Dehydrogenation of the resulting formamides (15) with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) gave the fully aromatised amines corresponding to methyl integriamide (17a).Bischler-Napieralski reaction of these amides (17) furnished the desired quaternary benzophenanthridine alkaloids (5).