Studies on the syntheses of heteroeyelie compounds. Part DVI . Synthesis of oxynilidine and nitidine

Kametani, Tetsuji; Kigasawa, Kazuo; Hiiragi, Mineharu; Kusama, O.

doi:10.1002/jhet.5570100107

Cited by 25 publications

(10 citation statements)

References 4 publications

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“…Rutaceae: Toddalia ( 230 UV: (EtOH) 229.5 UV: (CHClj)238(4.53), 283(4.60), 310(4.40), 325 sh (4.29X332) MS: 379 (M+, 12.9), 348 (100), 333 (17) (332) Sources: Rutaceae: Vagara (320) 53. OXYNITIDINE CJ 8.8Hz) 7.54d 7.17s C21H17NO,: 363.37334 MP: 284-285°(EtOH) (4,5,8,89,135) 290-293°(CHClrMeOH) (123) See also 17, 125, 126, 148, 176. UV: (EtOH) 251…”

Section: Angolinementioning

confidence: 98%

The Benzophenanthridine Alkaloids

Krane¹,

Fagbule²,

Shamma³

et al. 1984

J. Nat. Prod.

249

113

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Section: Angolinementioning

confidence: 98%

The Benzophenanthridine Alkaloids

Krane¹,

Fagbule²,

Shamma³

et al. 1984

J. Nat. Prod.

249

113

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“…Mechanism of Ketone-Acetal Equilibration. A great (5) de Lisi, R.; Goffredi, M.; Turco Liveri, V. J. Chem. Sac., Faraday Trans 1 1978, 74, 1096-1111.…”

Section: Discussionmentioning

confidence: 99%

“…The ^f/^h = ^ ß 2/[ 20] (4) kF + kH sums have been determined for different water concentrations, and the kF and kH values are calculated by means of eq 5 and 6. Typical data for 3-nitroaceto-kF = (kF + &H)/(1 + [H20]/KcoMeOH2) (5) = (&f + feH)/(l 4-KcaMe0H2/[H20]) (6) phenone at constant acid concentration are listed in Table I. Water concentrations therein are those calculated by eq 7 from the absorbances (AJx and (A")2 at equilibrium [H20] = KcaMe0H2(A" -C€ac)/(ceke -A.)…”

mentioning

confidence: 99%

Ring substituent effects on acetophenone dimethyl acetal formation. 2. Dual-parameter treatment of kinetic data for acid-catalyzed acetal formation and hydrolysis in methanol containing small amounts of water

Toullec¹,

El-Alaoui²

1985

J. Org. Chem.

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The rates of formation and hydrolysis of para-and meta-substituted acetophenone dimethyl acetals have been measured, by a water-concentration method, in methanol containing HBr and small amounts of water. The rate coefficients for pure anhydrous methanol have been extrapolated. Acid and water-concentration effects are consistent with the usual mechanism for acetal hydrolysis in water, but the rate-limiting step in the hydrolysis direction corresponds to water addition to the hemiacetal-yielding oxocarbenium ion. Substituent effects on both extrapolated rate coefficients fit the Young-Jencks-modified Yukawa-Tsuno equation. The validity of this equation and its usefulness for separating polar and conjugative effects are discussed.

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“…In 1973, Kametani and co‐workers have reported the total syntheses of nitidine ( 11 c ) and oxynitidine ( 9 d ) via a key benzyne mediated C−C bond‐forming reaction (Scheme ) . A reaction of α‐tetralone 22 a with the aryne ( 22 b ), generated in situ from 3,4‐dimethoxy bromobenzene, afforded α‐arylated tetralone 22 c .…”

Section: Synthetic Strategies For Benzo[c]phenanthridine Alkaloidsmentioning

confidence: 99%

Biosynthetic Relationships and Total Syntheses of Naturally Occurring Benzo[c]Phenanthridine Alkaloids

et al. 2019

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Benzo[c]phenanthridine alkaloids sharing a tetracyclic structural motif, are an important class of nitrogencontaining small molecules and are used for the treatment of a number of diseases. This review presents a comprehensive survey of the occurrence, chemistry, biochemistry, and biological activity of benzophenanthridine alkaloids. Synthetic approaches to a number of benzo[c]phenanthridine are disclosed in this Minireview. Biosynthetic Relationship of Tetrahydroisoquinoline and Benzo[c]phenanthridine AlkaloidsA plausible biogenetic connection between tetrahydroisoquinoline and benzo[c]phenanthridine alkaloids is shown in Scheme 1. Protopine (3 a) can undergo a demethylation followed by reductive amination to generate tetrahydroisoquinoline alkaloid, stylopine (2 a). The latter can further undergo an [a] Dr. oxidative CÀ N bond cleavage leading to intermediate aldehyde 4 a, which can form a new CÀ C bond (see, 4 c) assisted by in-situ prepared enamine. An elimination followed by oxidation leads to the synthesis of norsanguinarine (1 a).

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Studies on the syntheses of heteroeyelie compounds. Part DVI . Synthesis of oxynilidine and nitidine

Cited by 25 publications

References 4 publications

The Benzophenanthridine Alkaloids

The Benzophenanthridine Alkaloids

Ring substituent effects on acetophenone dimethyl acetal formation. 2. Dual-parameter treatment of kinetic data for acid-catalyzed acetal formation and hydrolysis in methanol containing small amounts of water

Biosynthetic Relationships and Total Syntheses of Naturally Occurring Benzo[c]Phenanthridine Alkaloids

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