Showing papers by "Keiichiro Fukumoto published in 1976"

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.

Studies on the Syntheses of Heterocyclic Compounds. DCLXIII. The Reaction of Pyridone Derivatives with Diazoalkane

Abstract: The reaction of 3-carboxy-1, 2-dihydro-1-methyl-2-oxopyridine (V) with diazomethane afforded 6, 7-dihydro-1, 6-dimethyl-7-oxopyrazolo [3, 4-c] pyridine (VI), 4, 5, 6, 7-tetrahydro-1, 6-dimethyl-7-oxopyrazolo [3, 4-c] pyridine (VII), and 1, 2-dihydro-3-methoxycarbonyl-1, 4-dimethyl-2-oxopyridine (VIII). 1-Ethyl-6, 7-dihydro-3, 6-dimethyl-7-oxopyrazolo [3, 4-c] pyridine (XXI), 8a-ethoxycarbonyl-1, 4, 4a, 7, 8, 8a-hexahydro-3, 4, 7-trimethyl-8-oxopyrido [3, 4-c] pyridazine (XXII), and 3-ethoxycarbonyl-4-ethyl-1, 2-dihydro-1-methyl-2-oxopyridine (XXIII) were obtained from the reaction of compound (V) with diazoethane. The treatment of 4-carboxy-1, 2-dihydro-1-methyl-2-oxopyridine (XXVIII) with diazomethane gave 1, 2-dihydro-4-methoxycarbonyl-1-methyl-2-oxopyridine (XXIX), 6-methoxycarbonyl-3-methyl-2-oxo-3-azabicyclo [4. 1. 0] hept-4-ene (XXX), and 1, 2-dihydro-4-methoxycarbonyl-1, 3-dimethyl-2-oxopyridine (XXXI). The reaction of compound (XXIX) with diazoethane afforded 3-ethyl-1, 2-dihydro-4-methoxycarbonyl-1-methyl-2-oxopyridine (XXXII), 6α-methoxycarbonyl-3, 7β-dimethyl-2-oxo-3-azabicyclo [4, 1, 0]-hept-4-ene (XXXIII), and 1-ethyl-6-methoxycarbonyl-3, 7-dimethyl-2-oxo-3-azabicyclo [4. 1. 0] hept-4-ene (XXXIV). In case of the treatment of 5-carboxy-1, 2-dihydro-1-methyl-2-oxopyridine (XXXV) and 1, 5-dihydro-1, 5-dioxo-3H-oxazolo [3, 4-a] pyridine (XXXVIII) with diazomethane, 1, 2-dihydro-5-methoxycarbonyl-1-methyl-2-oxopyridine (XXXVI) and 1, 2-dihydro-6-methoxycarbonyl-1-methyl-2-oxopyridine (XXXIX) were obtained, respectively.

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.

Novel stereospecific synthesis of a potential intermediate for preparation of tetracyclic diterpenes from dihydrobenzocyclobutene derivatives

Abstract: A potential intermediate, the ethano-octa-hydromethoxymethylphenanthrenone (12), for the synthesis of tetracyclic diterpenoids has been stereospecifically synthesised by an intramolecular cycloaddition of the o-quinodimethane (10) derived thermally from 5-n-butylthiomethylene-2-[2-(4-methoxydihydrobenzocyclobutenyl)ethyl]-2-methylcyclopentanone, followed by desulphurisation.

Studies on the syntheses of heterocyclic compounds. part dcxxxviii. simple synthesis of benz(d)indeno(1,2-b)azepine from 1-benzoyl-3,4-dihydroisoquinoline

Abstract: 1-Benzoyl-3,4-dihydroisoquinoline methiodides (13, 14, 15) were converted into 5-benzoyl-2,3-dihydro-1H-3-benzazepines (18, 19, 20), respectively, cyclization and reduction of which gave benz[d]indeno[l,2-b]azepines (27, 28, 29).

Studies on the syntheses of heterocyclic compounds. dclxiii. the reaction of pyridone derivatives with diazoalkane

Abstract: The reaction of 3-carboxy-1, 2-dihydro-1-methyl-2-oxopyridine (V) with diazomethane afforded 6, 7-dihydro-1, 6-dimethyl-7-oxopyrazolo [3, 4-c] pyridine (VI), 4, 5, 6, 7-tetrahydro-1, 6-dimethyl-7-oxopyrazolo [3, 4-c] pyridine (VII), and 1, 2-dihydro-3-methoxycarbonyl-1, 4-dimethyl-2-oxopyridine (VIII). 1-Ethyl-6, 7-dihydro-3, 6-dimethyl-7-oxopyrazolo [3, 4-c] pyridine (XXI), 8a-ethoxycarbonyl-1, 4, 4a, 7, 8, 8a-hexahydro-3, 4, 7-trimethyl-8-oxopyrido [3, 4-c] pyridazine (XXII), and 3-ethoxycarbonyl-4-ethyl-1, 2-dihydro-1-methyl-2-oxopyridine (XXIII) were obtained from the reaction of compound (V) with diazoethane. The treatment of 4-carboxy-1, 2-dihydro-1-methyl-2-oxopyridine (XXVIII) with diazomethane gave 1, 2-dihydro-4-methoxycarbonyl-1-methyl-2-oxopyridine (XXIX), 6-methoxycarbonyl-3-methyl-2-oxo-3-azabicyclo [4. 1. 0] hept-4-ene (XXX), and 1, 2-dihydro-4-methoxycarbonyl-1, 3-dimethyl-2-oxopyridine (XXXI). The reaction of compound (XXIX) with diazoethane afforded 3-ethyl-1, 2-dihydro-4-methoxycarbonyl-1-methyl-2-oxopyridine (XXXII), 6α-methoxycarbonyl-3, 7β-dimethyl-2-oxo-3-azabicyclo [4, 1, 0]-hept-4-ene (XXXIII), and 1-ethyl-6-methoxycarbonyl-3, 7-dimethyl-2-oxo-3-azabicyclo [4. 1. 0] hept-4-ene (XXXIV). In case of the treatment of 5-carboxy-1, 2-dihydro-1-methyl-2-oxopyridine (XXXV) and 1, 5-dihydro-1, 5-dioxo-3H-oxazolo [3, 4-a] pyridine (XXXVIII) with diazomethane, 1, 2-dihydro-5-methoxycarbonyl-1-methyl-2-oxopyridine (XXXVI) and 1, 2-dihydro-6-methoxycarbonyl-1-methyl-2-oxopyridine (XXXIX) were obtained, respectively.

Studies on the syntheses of heterocyclic compounds. part dcxxxvi. an alternative synthesis of pentazocine

Abstract: The important starting material in a synthesis of pentazocine (1) was easily prepared by treating gaseous formaldehyde with 2-lithio-2-butene. Both E- and Z-2-bromo-2-butenes (2, 3) gave the same Z...

Novel stereospecific synthesis of a potential intermediate for preparation of tetracyclic diterpenes from dihydrobenzocyclobutene derivatives

Abstract: A potential intermediate, the ethano-octa-hydromethoxymethylphenanthrenone (12), for the synthesis of tetracyclic diterpenoids has been stereospecifically synthesised by an intramolecular cycloaddition of the o-quinodimethane (10) derived thermally from 5-n-butylthiomethylene-2-[2-(4-methoxydihydrobenzocyclobutenyl)ethyl]-2-methylcyclopentanone, followed by desulphurisation.