Studies on the syntheses of heterocyclic compounds. DCXCII. A novel synthetic route to phthalideisoquinoline and spirobenzylisoquinoline type alkaloids.

Kametani, Tetsuji; Ohsawa, Tatsushi; Shoji, Hiromichi; Premila, M. S.; Ihara, Masataka; Fukumoto, Keiichiro

doi:10.1248/cpb.25.321

Cited by 12 publications

(4 citation statements)

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“…( ± )-Isocordrastine II (1e): 87% yield from 19e ; mp 167−169 °C (EtOH) (lit . mp 157−159 °C; , 166−167 °C; 167−169 °C; 169−170 °C; 169−171 °C; 170−171 °C). 1 H NMR (270 MHz) δ 2.28−2.40 (m, 1H), 2.57−2.72 (m, 2H), 2.93−3.03 (m, 1H), 2.60 (s, 3H), 3.72, 3.79, 3.86, 3.91 (each s, each 3H), 4.12, 5.58 (each d, J = 4.0 Hz, each 1H), 6.23, 6.42, 6.62, 7.23 (each s, each 1H). ,− …”

Section: Methodsmentioning

confidence: 99%

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation¹

et al. 1999

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6,7,3',4'-Alkoxy-substituted 1-(2'-bromobenzoyl)-3,4-dihydroisoquinoline methiodides 17 were treated with sodium borohydride in methanol or acetic acid to give erythro-1-(2'-bromo-alpha-hydroxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinolines 19. Treatment of 17 with lithium aluminum hydride in tetrahydrofuran gave the threo-isomer 20 in preference to the erythro 19. On the basis of studies on palladium(0)-catalyzed carbonylation of 2-bromo-3,4-dimethoxybenzyl alcohol to 6,7-dimethoxyphthalide, amino alcohol 19 or 20 was treated with a catalytic amount of palladium(II) acetate and triphenylphosphine in an atmosphere of carbon monoxide in the presence of chlorotrimethylsilane and potassium carbonate in boiling toluene to give the corresponding erythro- or threo-types of phthalideisoquinoline alkaloids 1 or 2, respectively. One-pot cyclization of the erythro-amino alcohols 19 was achieved by heating in N,N-dimethylformamide containing potassium carbonate to give 2,3,8,9- or 2,3,9,10-alkoxy-substituted 5,6-dihydroindolo[2,1-a]isoquinolines 3, which have a unique tetracyclic skeleton characteristic of dibenzopyrrocoline alkaloids. Similarly, palladium(0)-catalyzed carbonylation of 1-(2'-bromobenzyl)tetrahydroisoquinolines 21 in the presence of excess potassium carbonate was found to give 8-oxoberbines 22, which on reduction with lithium aluminum hydride can be converted to protoberberine alkaloids 4.

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Section: Methodsmentioning

confidence: 99%

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation¹

et al. 1999

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“…Namely, along with (or even instead of) common reaction products, i. e. 4‐acyl benzazepines 3 , their 5‐acyl isomers 6 , the formal products of the 1,2‐acyl migration in 3 , were formed (Scheme , Table ). These compounds are the representatives of almost unknown 5‐acyl‐1,2‐dihydro‐3‐benzazepines …”

Section: Methodsmentioning

confidence: 99%

Unusual 1,2‐Acyl Rearrangement Accompanying Ring Expansion Reaction of Alkaloid Cotarnine under the Action of α‐Haloketones: a New Route to 5‐Acyl‐1,2‐dihydro‐3‐benzazepine Moiety

et al. 2016

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The ring expansion reaction of the isoquinoline alkaloid cotarnine with α‐haloketones which normally leads to the formation of 4‐acyl‐7,8‐metylenedioxy‐1,2‐dihydro‐3‐benzazepines, in some cases, occurs with an unusual, non‐acid‐catalytic 1,2‐acyl rearrangement. As a result, corresponding 5‐acyl isomers are formed. A carbocation mechanism of the rearrangement was proposed. It involves formation of 4‐acyl‐5‐hydroxy‐7,8‐metylenedioxy‐1,2,3,4‐tetrahydro‐3‐benzazepines and their dissociation (as leuko bases) into corresponding benzazepine carbocations. As it follows from DFT calculations, these carbocations are prone to almost barrierless intracationic 1,2‐acyl group migration with conversion into corresponding isomeric carbocations. At the last stage of the reaction, these cations are deprotonated into final rearranged compounds.

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“…High-resolution mass spectrum: caled for CagH^NCb, 385.1160; found, 385.1149. cis-l-Hydroxy-2-methoxy-7,8-(methylenedioxy)-12,13-dimethoxy-14-oxoaporhoeadane (15). A slurry of 6 (0.11 g, 0.27 mmol) was reduced with sodium borohydride as above to afford after preparative TLC as the major product 15: 0.08 g (74%); mp 204-205 °C (MeOH); i/malCHC1s 1695, 3400 cm"1; NMR (CDC13) 2.S-4.2 (br m, 4 H, CH2CH2), 2.75 (s, 3 H, C-2, OCH3), 3.85 (s, 3 H, OCH3), 3.96 (s, 3 H, OCH3), 4.75 (s, 1 , H-l), 5.84 (s, 2 H, OCH20), 6.54 (s, 1 , H-6), 6.91 (s, 1 , H-9), 6.98, 7.32 (AB q, 2 H, J = 8.…”

Section: Methodsmentioning

confidence: 99%

“…5 Hz, H-10 and H-ll) High-resolution mass spectrum: caled for C22H23N07, 413.1468; found, 413.1457. cis-l,2-Dimethoxy-7,8-(methylenedioxy)-12,13-dimethoxy- 14-oxoaporhoeadane (18). A solution of the cis hydroxy ether 15 (0.21 g, 0.53 mmol) in THF-DMF (10:2) (20 mL) was treated with sodium hydride (0.2 g) and after 5 min, methyl iodide (1 mL) was added. The cloudy mixture was stirred for 5 h. A little methanol was added, and then water and chloroform were added.…”

Section: Methodsmentioning

confidence: 99%

Chemistry of highly oxidized aporhoeadanes

Moniot¹,

Hindenlang²,

Shamma³

1979

J. Org. Chem.

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Studies on the syntheses of heterocyclic compounds. DCXCII. A novel synthetic route to phthalideisoquinoline and spirobenzylisoquinoline type alkaloids.

Cited by 12 publications

References 0 publications

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation¹

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation¹

Unusual 1,2‐Acyl Rearrangement Accompanying Ring Expansion Reaction of Alkaloid Cotarnine under the Action of α‐Haloketones: a New Route to 5‐Acyl‐1,2‐dihydro‐3‐benzazepine Moiety

Chemistry of highly oxidized aporhoeadanes

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Studies on the syntheses of heterocyclic compounds. DCXCII. A novel synthetic route to phthalideisoquinoline and spirobenzylisoquinoline type alkaloids.

Cited by 12 publications

References 0 publications

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation1

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation1

Unusual 1,2‐Acyl Rearrangement Accompanying Ring Expansion Reaction of Alkaloid Cotarnine under the Action of α‐Haloketones: a New Route to 5‐Acyl‐1,2‐dihydro‐3‐benzazepine Moiety

Chemistry of highly oxidized aporhoeadanes

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Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation¹

Synthesis of Phthalideisoquinoline and Protoberberine Alkaloids and Indolo[2,1-a]isoquinolines in a Divergent Route Involving Palladium(0)-Catalyzed Carbonylation¹