Showing papers by "Keiichiro Fukumoto published in 1977"

Studies on the syntheses of heterocyclic compounds. 675. A facile regiospecific and stereocontrolled synthesis of a diterpene alkaloid intermediate from benzocyclobutenes

Abstract: Das aus der Cyanpropionsaure (I) erhaltliche Benzocyclobuten (II) reagiert mit dem Jodid (III) (mittels ublicher Methoden aus α-Methylacetessigsauremethylester erhaltlich) zu dem Kondensationsprodukt (IV), das bei Thermolyse regiospezifisch und stereoselektiv in das Octalin (V) ubergeht.

A Biomimetic Synthesis of Benzo[c]Phenanthridine Alkaloid Nitidine

Abstract: Oxidation of 1,2,3,4-tetrahydro-7-hydroxy-6-methoxy-3-(4,5-dimethoxy-2-vinylphenyl)-2-methylisoquinoline (10), derived from the corresponding berbine methiodide (8), with lead tetraacetate, followed by acidic treatments, gave 5,6-dihydro-8-hydroxy-2,3,9-trimethoxy-5-methylbenzo[c]phenenthridine (20). By a similar procedure, 1,2,3,4-tetrahydro-7-hydroxy-6-methoxy-3-(4,5-methylenedioxy-2-vinylphenyl)-2-methylisoquinoline (11) was converted to cis-8-acetoxy-4b,5,6,10b-tetrahydro-9-methoxy-5-methyl-2,3-methylenedioxybenzo[c]phenanthridine (17), whose hydrolysis with hydrochloric acid followed by methylation with diazomethane furnished dihydronitidine (22).

Studies on the syntheses of heterocyclic compounds. dclxxii. a synthesis of coralydine and o-methylcorytenchirine by thermolysis of benzocyclobutene

Abstract: A new synthetic method for the tetrahydro-8-methylprotoberberines, coralydine (VIb) and O-methylcorytenchirine (VIa), was described. 3, 4-Dimethoxyacetophenone (IX) was converted into 4, 5-dimethoxy-2-methylbenzocyclobutene-1-carboxylic acid (XVII) by our method, which was condensed with homoveratrylamine to give N-(3, 4-dimethoxy-phenethyl)-4, 5-dimethoxy-2-methylbenzocyclobutene-1-carboxamide (XVIII). Thermolysis of the resulting 3, 4-dihydroisoquinoline hydrochloride (XXIII), which was obtained by Bischler-Napieralski reaction of XVIII, in bromobenzene followed by sodium borohydride reduction gave VIa and VIb.