| 1. |
- Bergman, Jan, et al.
(author)
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Studies of the reactions between indole-2,3-diones (isatins) and 2-aminobenzylamine
- 2003
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 59:7, s. 1033-1048
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Journal article (peer-reviewed)abstract
- Reflux of equimolecular amounts 2-aminobenzylamine and isatins in acetic acid produced indolo[3,2-c]quinolin-6-ones in good yields. A proposed mechanism involving initial formation of a spiro compound is given. This isolable intermediate subsequently rearranges via a sequential isocyanate ring opening and a cyclisation process to a urea derivative which finally cyclized to the indolo[3,2-c]quinolin-6-ones. The urea derivative could be prepared separately and cyclized selectively to indolo[3,2-c]quinolin-6-one. Reaction of N-acetylisatin with 2-aminobenzylamine at room temperature yielded the 1,4-benzodiazepinone 3-(2-acetamidophenyl)-1,5-dihydro-1,4-benzodiazepin-2one whereas its isomer 2(2-acetamidophenyl)-4,5-dihydro-1,4-benzodiazepin-3-one was obtained from 2-(2-acetylaminophenyl)-N-(2-aminobenzyl)-2-oxoacetamide in acetic acid at room temperature. The previously unknown linear isomer of indolo[3,2-c]quinolin-6-one, i.e. indolo[2,3-blquinolin-11-one, has been prepared by thermal (260degreesC) cyclization of methyl 2-phenylamino indole-3-carboxylate, which in turn was prepared in two steps from methyl indole-3-carboxyl ate. (C) 2003 Elsevier Science Ltd. All rights reserved.
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| 2. |
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| 3. |
- Bergman, Jan, et al.
(author)
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Reactions of 1,2-bis(1H-indol-2-yl)ethane : Formation of indolo[2,3-c]carbazole and cyclohept[1,2-b : 5,4-b ']bisindole derivatives
- 2000
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 56:13, s. 1911-1916
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Journal article (peer-reviewed)abstract
- 1,2-Bis(1H-indol-2-yl)ethane (9) has been prepared and converted into indolo[2,3-c]carbazole (8) using palladium acetate in refluxing acetic acid. Reaction of 9 with CoF3 in hot TFA led to isolation of cyclohept[1,2-b:5,4-b']bisindole derivatives 11 and 12, which could be elaborated into further derivatives. Treatment of 9 with orthoesters, aldehydes and ketones under acidic conditions afforded additional bisindoles containing a seven-membered ring.
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| 4. |
- Bergman, Jan, et al.
(author)
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Synthesis of 4-oxo-4,5-dihydro-3H-pyrrolo[2,3-c]quinoline-1-carboxylic acid ethyl ester and its isomer 1-oxo-2,9-dihydro-1H-beta-carboline-4-carboxylic acid ethyl ester
- 2002
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:45, s. 9179-9185
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Journal article (peer-reviewed)abstract
- 4-Oxo-4,5-dihydro-3H-pyrrolo[2,3-c]quinoline-1-carboxylic acid ethyl ester was obtained when TosMIC was reacted with 3-methylene-oxindole acetic acid ethyl ester. An alternative synthesis to this pyrroloquinolone was performed via a reduction of a 2,3,4-trisubstituted pyrrole obtained in turn by treatment of a vinyl sulfone with ethyl isocyanoacetate under basic conditions. A beta-carboline, isomeric with the pyrroloquinolone, was synthesised utilizing a tosylimine.
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| 5. |
- Bergman, Jan, et al.
(author)
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Synthesis of cyclopent[b]indolones
- 1990
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 46:17, s. 6067-6084
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Journal article (peer-reviewed)abstract
- A number of cyclopent[b]indol-1-ones as well as -3-ones have been synthesized, using a new methodology involving intramolecular ring closure of α,β-unsaturated acylindoles. In some cases 1,2,3,4-tetrahydrocarbazol-4-ones were obtained. This methodology was used in the syntheses of the indole alkaloid yuehchukene and the carbazole alkaloid analogue demethoxycarbazomycin B.
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| 6. |
- Bergman, Jan, et al.
(author)
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Synthesis of indolocarbazole quinones; potent aryl hydrocarbon receptor ligands
- 2002
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:7, s. 1443-1452
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Journal article (peer-reviewed)abstract
- Syntheses of indolo[2,3-b]carbazole-6,12-dione and the isomeric indolo[3,2-b]carbazole-6,12-dione, an extremely efficient inducer of the aryl hydrocarbon (Ah) receptor are described. Initial oxidation of the parent indolo[3,2-b]carbazole followed by several different ring-closing strategies produced the latter compound. Entries into syntheses of unsymmetrical 6,12-disubstituted indolo[2,3-b]carbazoles are also described.
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| 7. |
- Garg, Neeraj, et al.
(author)
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Preparation of cis-5-methoxy-and-7-methoxy-1-acetoxy-1,2,3,4,4a,10a-hexahydro-9(10H)-phenanthrenone. An epoxide-arene reaction involving a selective 1,2-alkyl shift rearrangement
- 1996
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 52:48, s. 15209-15224
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Journal article (peer-reviewed)abstract
- The preparation of cis-1α-acetoxy-7-methoxy-1,2,3,4,4a,10a-hexahydro-9(10H)- phenanthrenone 5 was accomplished starting from 6-methoxy-1-tetralone. Reduction of 7-methoxy-1,2,3, 4,9,10-hexahydro-1-oxo-phenanthrene 8, acetylation and subsequent oxidation delivered 5. Application of an analogus procedure to the preparation of cis-1β-acetoxy-5-methoxy-1,2,3,4,,4a,10a-hexahydro-9(10H)- phenanthrenone 6 was not feasible. A more elaborate route was developed for the synthesis of compound 6, where an epoxide-arene reaction involving a 1,2-alkyl shift rearrangement, constituted a highly selective key transformation. The compounds 5 and 6 were prepared. A route was developed for the synthesis of compound 6, where an epoxide-arene reaction involving a 1,2-alkyl shift rearrangement, constituted a highly selective key transformation.
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| 8. |
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| 9. |
- Janosik, Tomasz, et al.
(author)
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Synthesis of the marine alkaloids rhopaladins A, B, C and D
- 2002
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In: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:14, s. 2813-2819
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Journal article (peer-reviewed)abstract
- The total synthesis of all four known rhopaladins, A-D, isolated from the Okinawan marine tunicate Rhopalaea sp., in two synthetic steps is described, involving an imidate based cyclization with tryptophan esters as the key step to afford the appropriately substituted imidazolinone unit. A short and efficient new synthesis of indol-3-yl-carbonyl nitriles from indol-3-yl-carboxaldehydes and trimethylsilyl cyanide, followed by oxidation with DDQ is also described.
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| 10. |
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