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  • 1. Bergander, L
    et al.
    Wahlström, Niklas
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Alsberg, T
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Rannug, A
    Rannug, U
    Characterization of in vitro metabolites of the aryl hydrocarbon receptor ligand 6-formylindolo[3,2-b] carbazole by liquid chromatography-mass spectrometry and NMR.2003In: Drug Metabolism And Disposition, ISSN 0090-9556, E-ISSN 1521-009X, Vol. 31, no 2, p. 233-241Article in journal (Refereed)
    Abstract [en]

    The tryptophan photoproduct 6-formylindolo[3,2-b] carbazole (FICZ) exhibits the highest aryl hydrocarbon receptor (AhR) binding affinity reported so far. In different cells, in vitro, both extracts of UV-irradiated tryptophan and the synthesized pure compound FICZ induce a rapid and transient expression of AhR-regulated genes. The transient induction suggests that the biotransformation gene battery induced by AhR activation takes part in a metabolic degradation of the ligand, whereby a low steady-state level is regained. The down-regulation of AhR-regulated gene expression was previously shown to be dependent on cytochrome P450 1A1 (CYP1A1). Metabolism of FICZ generates five major metabolites, which appeared as three peaks (M1-M3) in the high performance liquid chromatography. The aim of the present study was to use rat liver S9 from Aroclor-pretreated rats to produce large enough quantities of FICZ metabolites for structure characterization and to determine their product precursor relationship. NMR analysis of large combined fractions of the metabolites indicated that M3 and M2 contained 2 isomers, respectively. By means of liquid chromatography-mass spectrometry (negative ion electrospray mode) and NMR spectroscopy (by H-1-NMR, correlation spectroscopy, and nuclear Overhauser effect spectroscopy techniques) five metabolites of FICZ were identified, and their structures were elucidated. The molecular weights of the two M3 isomers were 300 and both M2 and M1 compounds demonstrated molecular weights of 316, corresponding to addition of one (M3) and of two oxygen (M2 and M1), respectively. The structures were assigned as 2- and 8-hydroxy (M3), 2,10- and 4,8-dihydroxy (M2) and 2,8-dihydroxy derivatives of indolo[3,2-b] carbazole-6-carboxaldehyde (6-formylindolo[ 3,2-b] carbazole).

  • 2.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Engqvist, Robert
    Karolinska Institute.
    Stålhandske, C
    Chemical Centre, Lund.
    Wallberg, H
    KTH.
    Studies of the reactions between indole-2,3-diones (isatins) and 2-aminobenzylamine2003In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 59, no 7, p. 1033-1048Article in journal (Refereed)
  • 3.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap.
    Janosik, T
    Koch, E
    Pelcman, B
    Acid-induced dimerization of 3-(1H-indol-3-yl)maleimides. Formation of cyclopentindole derivatives2000In: JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1, ISSN 1470-4358, no 16, p. 2615-2621Article in journal (Refereed)
    Abstract [en]

    Acid-induced dimerizations of 3-substituted maleimides have been investigated, leading to e.g. the cyclopentindole 9 and the deeply coloured spiro compounds 24 and 25 in good yields. 3-(1H-Indol-3-yl)maleimide 6b readily gave the cycloaddition products 13-15 on treatment with appropriate dienophiles. In addition, several related 3,3-di-(1H-indol-3-yl)succinimides have been prepared and studied.

  • 4.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap.
    Janosik, T
    Yudina, L
    Desarbre, E
    Lidgren, G
    Venemalm, L
    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 derivatives2000In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 56, no 13, p. 1911-1916Article in journal (Refereed)
    Abstract [en]

    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.

  • 5.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Janosik, Tomasz
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Recent progress in the chemistry of sulfur-containing indoles2002In: Progress in Heterocyclic Chemistry, ISSN 0959-6380, Vol. 14, no C, p. 1-18Article in journal (Refereed)
  • 6.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Janosik, Tomasz
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Wahlström, Niklas
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Indolocarbazoles2001In: Advances in Heterocyclic Chemistry, ISSN 0065-2725, E-ISSN 1557-8429, Vol. 80, p. 1-71Article, review/survey (Refereed)
  • 7.
    Bergman, Jan
    et al.
    Södertörn University, School of Life Sciences.
    Johnson, Ann-Louise
    A short synthesis of the carbazole alkaloid clausine E2006In: Organic preparations and procedures international, ISSN 0030-4948, E-ISSN 1945-5453, Vol. 38, no 6, p. 593-599Article in journal (Refereed)
  • 8.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap.
    Koch, E
    Pelcman, B
    Coupling reactions of indole-3-acetic acid derivatives. Synthesis of arcyriaflavin A2000In: JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1, ISSN 1470-4358, no 16, p. 2609-2614Article in journal (Refereed)
    Abstract [en]

    The bisindolesuccinic acid methyl ester 10 was obtained by an iodine-promoted coupling of the dianion 9. The diester was converted to the N-benzylimide 12, which was oxidatively cyclized to the indolo[2,3-a]pyrrolo[3,4-c]carbazole 15. The diester 10 could be directly transformed to the known indolocarbazole diester 27 via acid-induced intramolecular cyclization in TFA. The same methodology gave arcyriaflavin A 4 from the succinimide 18b.

  • 9.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap.
    Rehn, S
    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 ester2002In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 58, no 45, p. 9179-9185Article in journal (Refereed)
    Abstract [en]

    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.

  • 10.
    Bergman, Jan
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Wahlström, Niklas
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Yudina, L N
    Tholander, J
    Lidgren, G
    Synthesis of indolocarbazole quinones; potent aryl hydrocarbon receptor ligands2002In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 58, no 7, p. 1443-1452Article in journal (Refereed)
    Abstract [en]

    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.

  • 11.
    Engqvist, Robert
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    An improved synthesis of neocryptolepine2004In: Organic preparations and procedures international, ISSN 0030-4948, E-ISSN 1945-5453, Vol. 36, no 4, p. 386-390Article in journal (Refereed)
  • 12.
    Engqvist, Robert
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Synthesis of benzothiopyrano[2,3-b]indol-11-one and benzopyrano[2,3-b]indol-11-one2003In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 59, no 48, p. 9649-9653Article in journal (Refereed)
    Abstract [en]

    The fused heterocycles benzothiopyrano[2,3-b]indol-11-one and benzopyrano[2,3-b]indol-11-one, have been prepared from methyl 3-indole carboxylate in two steps.

  • 13.
    Engqvist, Robert
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Javaid, Atif
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Synthesis of thienodolin2004In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 12, p. 2589-2592Article in journal (Refereed)
    Abstract [en]

    We report a total synthesis of the alkaloid thienodolin (1a), as well as its 5-chloro isomer 1b and its unsubstituted analogue 1c, in three steps from the corresponding oxindoles Ba-c. The preparation was achieved through an initial Vilsmeier-Haack-Arnold reaction (chloro-formylation) followed by protection at the indole nitrogen, creation of the fused thiophene ring by nucleophilic substitution at the 2-position and an intramolecular cyclization using mercaptoacetamide. This gave 1a, 1b and 1c in total yields of 42%, 35% and 37%, respectively.

  • 14.
    Engqvist, Robert
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Stensland, Birgitta
    AstraZeneca.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Reduction of indolo[2,3-b]quinoxalines2005In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 61, no 18, p. 4495-4500Article in journal (Refereed)
    Abstract [en]

    Reduction of indolo[2,3-b]quinoxalines with zinc in the presence of an anhydride gave N,N-diacyl trapped 6,11-dihydroindolo[2,3-b]quinoxalines in 43-92% yields. When the reduction with zinc was performed in TFA/TFAA, an unexpected ring opened product was isolated in 49% yield. The structure of this product could be identified as 1,2-dihydro-1-trifluoroacetyl-3-[(2-trifluoroacetylamino)phenyl]quinoxal ine.

  • 15. Janosik, T
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Oxidative coupling of indoline-2-thione or oxindole: Formation of cyclic and acyclic indole trimers2002In: Heterocycles, ISSN 0385-5414, E-ISSN 1881-0942, Vol. 57, no 7, p. 1273-1278Article in journal (Refereed)
    Abstract [en]

    Oxidation of indoline-2-thione using p-toluenesulfonyl azide produced a modest yield of the structurally novel cyclic sulfur containing indole trimer (12). In contrast, the oxidation of oxindole with iodine instead produced an acyclic trimeric indole derivative.

  • 16.
    Janosik, Tomasz
    et al.
    Dartmouth College, Hanover, United States .
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Five-membered ring systems: Pyrroles and benzo derivatives2003In: Progress in Heterocyclic Chemistry, ISSN 0959-6380, Vol. 15, no C, p. 140-166Article in journal (Refereed)
  • 17.
    Janosik, Tomasz
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Five-membered ring systems: thiophenes and Se/Te analogues2005In: Progress in heterocyclic chemistry., ISSN 0959-6380, Vol. 17, p. 84-108Article, review/survey (Other academic)
  • 18.
    Janosik, Tomasz
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Five-membered ring systems: thiophenes and Se/Te analogues2007In: Progress in Heterocyclic Chemistry, ISSN 0959-6380, Vol. 18, p. 126-149Article, review/survey (Other academic)
  • 19.
    Janosik, Tomasz
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Pelkey, Erin T.
    Hobart and William Smith Colleges, Geneva, NY, United States.
    Chapter 5.2 Five-membered ring systems: Pyrroles and benzo derivatives2005In: Progress in Heterocyclic Chemistry, ISSN 0959-6380, Vol. 16, p. 128-155Article, review/survey (Other academic)
    Abstract [en]

    This chapter discusses the progress in synthesis and chemistry of pyrroles, indoles, and related fused ring systems. Several specialized reviews on the chemistry of indoles and pyrroles have appeared during the reporting period, providing more in-depth coverage. A comprehensive review on pyrrole natural products has appeared as well as a more limited one on the synthetic chemistry involving the pyrrole natural products roseophilin and prodigiosin is illustrated in this chapter. Likewise, the synthetic efforts in the field of the pyrrole-imidazole class of alkaloids have been covered. The isolation and synthesis of indole alkaloids containing a non-rearranged monoterpenoid unit is discussed in this chapter.

  • 20.
    Janosik, Tomasz
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Romero, Ivan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Stensland, B
    Stålhandske, C
    Marques, M M B
    Santos, M M M
    Lobo, A M
    Prabhakar, S
    Duarte, M F
    Florencio, M H
    Synthetic, spectroscopic, and X-ray crystallographic studies of [1,2,7,8]tetrathiacyclododecino[4,3-b: 5,6-b': 10,9-b": 11,12-b''']tetraindoles2002In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 8, p. 1392-1396Article in journal (Refereed)
    Abstract [en]

    Two conformationally different [1,2,7,8]tetrathiacyclododecino[4,3-b:5,6-b':10,9-b":11,12-b''']tetraind oles 9a and 9b have been isolated in good yields, and the existence of a third conformer 9c in solution was demonstrated by mass spectrometry and H-1 NMR spectroscopy. The interconversions of the tetraindoles 9a-c have also been studied. The conformation of 9b was confirmed by X-ray crystallography, while the conformations of 9a and 9b were assigned on the basis of spectroscopic data, and were also supported by molecular modelling studies. In addition, the elusive dithiin 3 was isolated and the structure was proven by X-ray crystallography.

  • 21.
    Janosik, Tomasz
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Johnson, Ann-Louise
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Synthesis of the marine alkaloids rhopaladins A, B, C and D2002In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 58, no 14, p. 2813-2819Article in journal (Refereed)
    Abstract [en]

    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.

  • 22. Janosik, Tomasz
    et al.
    Shirani, Hamid
    Wahlström, Niklas
    Malky, Ilham
    Stensland, Birgitta
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Efficient sulfonation of 1-phenylsulfonyl-1H-pyrroles and 1-phenylsulfonyl-1H-indoles using chlorosulfonic acid in acetonitrile2006In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 62, no 8, p. 1699-1707Article in journal (Refereed)
    Abstract [en]

    The sulfonation of various 1-phenylsulfonyl-1H-pyrroles and 1-phenylsulfonyl-1H-indoles using chlorosulfonic acid in acetonitrile has been studied, leading to the development of a clean and operationally simple protocol allowing direct synthesis of the corresponding 1-phenylsulfonyl-1H-pyrrole-3-sulfonyl chlorides and 1-phenylsulfonyl-1H-indole-3-sulfonyl chlorides, respectively, both of which may be easily converted to various sulfonamide derivatives by treatment with nitrogen nucleophiles. Efficient and selective removal of the phenylsulfonyl- or tosyl groups in the sulfonamide series may be achieved under mild conditions.

  • 23.
    Janosik, Tomasz
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Stensland, B
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Sulfur-rich heterocycles from 2-metalated benzo[b]thiophene and benzo[b]furan: Synthesis and structure2002In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 67, no 17, p. 6220-6223Article in journal (Refereed)
    Abstract [en]

    The reaction of 2-lithiated benzo[b]thiophene with 8 equiv of elemental sulfur was found to give pentathiepino[6,7-b]benzo[d]thiophene. In contrast, treatment of 2-lithiated benzo[b]furan with sulfur under similar conditions produced the interesting ring system bis(benzo[4,5]-furo)[2,3-e:3',2'-g][1,2,3,4]tetrathiocine. Both of these new cyclic polysulfides were studied by X-ray crystallography. Two polymorphic forms of pentathiepino[6,7-b]benzo[d]thiophene were found, displaying similar conformations but different packing schemes, which was also evident from powder diffraction data.

  • 24. Johnson, A L
    et al.
    Janosik, T
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap.
    Synthesis of the diketopiperazine dipodazine2002In: ARKIVOC, ISSN 1551-7004, E-ISSN 1551-7012, p. 57-61Article in journal (Refereed)
    Abstract [en]

    The diketopiperazine derivative dipodazine (1), isolated from Penicillium dipodomyis, has been synthesized via a stereoselective aldol condensation from N-protected indole-3-carboxaldehyde and 1,4-diacetyl-2,5-piperazinedione (3) in the presence of cesium carbonate.

  • 25. Johnson, A. -L
    et al.
    Slätt, J.
    Janosik, T.
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Stereoselective synthesis and isomerization of the indole alkaloid murrayacarine2006In: Heterocycles, ISSN 0385-5414, E-ISSN 1881-0942, Vol. 68, no 10, p. 2165-2170Article in journal (Refereed)
    Abstract [en]

    A short and efficient stereoselective synthesis of the indole alkaloid murrayacarine is described, including studies on its acid-induced isomerization.

  • 26. Johnson, Ann-Louise
    et al.
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Synthetic approaches towards an indole alkaloid isolated from the marine sponge Halichondria melanodocia2006In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 62, no 47, p. 10815-10820Article in journal (Refereed)
    Abstract [en]

    The exocyclic analogue of the indole alkaloid isolated from the marine sponge Halichondria melanodocia has been prepared via olefination of a phosphonoester derived from 3-(2-bromoacyl)indole. The formation of an unexpected indolylazepine is also discussed.

  • 27.
    Johnson, Ann-Louise
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Sjögren, M
    Bohlin, L
    Synthesis of barettin2004In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 60, no 4, p. 961-965Article in journal (Refereed)
    Abstract [en]

    The indole alkaloid barettin (with bromine in 6-position), isolated from the marine sponge Geodia Barretti, has been synthesised via a Horner-Wadsworth-Emmons type reaction from 6-bromoindole-3-carboxaldehyde to introduce the dehydro-functionality. Subsequent deprotection and cyclisation afforded the natural product in Z-conformation.

  • 28. Jouve, Karine
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Oxidative cyclization of N-methyl- and N-benzoylpyridylthioureas. Preparation of new thiazolo[4,5-b] and [5,4-b]pyridine derivatives2003In: Journal of Heterocyclic Chemistry, ISSN 0022-152X, E-ISSN 1943-5193, Vol. 40, no 2, p. 261-268Article in journal (Refereed)
  • 29. Nordling, M M
    et al.
    Nygren, Jonas
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Sundberg, K
    Rafter, J J
    Toxicological characterization of a novel in vivo benzo[a]lpyrene metabolite, 7-oxo-benz[d]anthracene-3,4-dicarboxylic acid anhydride2002In: Chemical Research in Toxicology, ISSN 0893-228X, E-ISSN 1520-5010, Vol. 15, no 10, p. 1274-1280Article in journal (Refereed)
    Abstract [en]

    Recently, we described a new in vivo pathway in the metabolism of benzo[a]pyrene (BP) that involves an opening of the aromatic ring system. One of the products of this pathway, isolated from rat urine, was the anhydride of 7-oxo-benz[d]anthracene-3,4-dicarboxylic acid (ABADA). We have now investigated the effect of ABADA on several cellular targets, known to be important in tumor formation. ABADA was as efficient as BP-7,8-diol-9,10-epoxide in inducing direct strand breaks but not alkali labile sites in DNA in HT-29 cells and exhibited weak mutagenic activity in Salmonella typhimurium strain TA 102. The cytotoxicity of ABADA to HCT 116 cells appeared to be due to apoptosis, as caspase-3 activity and poly-ADP-ribose polymerase (PARP) cleavage was observed. COX-2 promoter activity was induced by ABADA in HCT 116 cells. In conclusion, this novel metabolic pathway may also be contributing to the carcinogenicity of BP.

  • 30. Rehn, Stanley
    et al.
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institute.
    The reaction between 3-aminocrotonates and oxindole-3-ylidene derivatives: synthesis of highly substituted pyrroles2005In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 61, no 12, p. 3115-3123Article in journal (Refereed)
    Abstract [en]

    The reaction between 3-aminocrotonates and 3-acetonylideneoxindole in refluxing toluene resulted in 2-pyrrolo-3 '-yloxindoles in high yields (around 90%). At room temperature the 2-pyrrolo-3 '-yioxindoles exists as keto-enol tautomers. Treatment with POCl3 yielded the 2-chloro-3-pyrrolyl indole, which gave the pyrrolo annulated indolopyran-2-one upon basic hydrolysis of 2-chloro-3-pyrrolyl indole methyl ester.

  • 31.
    Rehn, Stanley
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Stensland, B
    The three-component reaction between isatin, alpha-amino acids, and dipolarophiles2004In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 2, p. 413-418Article in journal (Refereed)
    Abstract [en]

    3-Spiro[pyrrolidino-oxindoles] were prepared in high yields from a three-component reaction between isatin, an alpha-amino acid, and a dipolarophile. Both N-substituted and N-unsubstituted alpha-amino acids were used as the amine component.

  • 32. Rewcastle, G W
    et al.
    Janosik, Tomasz
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Reactions of 2-lithiated indoles with elemental sulfur. Formation of pentathiepino[6,7-b]indoles and indoline-2-thiones2001In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 57, no 33, p. 7185-7189Article in journal (Refereed)
    Abstract [en]

    The reactions of 2-lithiated indole and 1-methylindole with elemental sulfur have been studied, leading e.g. to a rational approach to pentathiepino[6,7-b]indoles 5 and 10. Notable amounts of the previously known tetrathiocino[5,6-b:8,7-b ' ]diindole 11 could be observed as a side reaction in the preparation of 10. Treatment of the anions of indoline-2-thiones 6 or 7 with sulfur also gave the pentathiepins 5 or 10, respectively. In addition, a convenient and clean lithiation route to indoline-2-thione (6) has been developed.

  • 33. Ruda, M C
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Koehler, K
    Liu, Y
    A solution-phase procedure for the preparation of 4-azasteroid numetics2003In: Heterocyclic Communications, ISSN 0793-0283, E-ISSN 2191-0197, Vol. 9, no 6, p. 571-574Article in journal (Refereed)
  • 34. Ruda, M C
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Wu, J
    Preparation of N-alkylated pyridones via selective N-alkylation of 2-alkoxypyridines on solid phase2002In: Journal of combinatorial chemistry, ISSN 1520-4766, E-ISSN 1520-4774, Vol. 4, no 5, p. 530-535Article in journal (Refereed)
    Abstract [en]

    Regioselective solid-phase synthesis of N-alkylated 2-pyridones has been carried out starting from 2-halopyridines. Variously substituted 2-halopyridines were linked to a Wang resin in quantitative yields to afford 2-alkoxypyridines. The coupled products were then reacted with a variety of alkyl halides, resulting in tandem alkylation and cleavage from the resin to generate N-alkylated pyridones With no detectable traces of O-alkylated products. The scope and limitations of this exceptionally selective reaction have been studied.

  • 35. Ruda, M
    et al.
    Kann, N
    Gordon, S
    Bergman, Jan
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Nelson, W
    Agback, P
    Hagberg, L
    Koehler, K F
    Solid-phase synthesis of a 6-phenylquinolin-2(1H)-one library directed toward nuclear hormone receptors2005In: Journal of combinatorial chemistry, ISSN 1520-4766, E-ISSN 1520-4774, Vol. 7, no 4, p. 567-573Article in journal (Refereed)
    Abstract [en]

    A library of 6-phenylquinolin-2(1H)-ones with diversity at position I and the ortho, meta, and para positions of the pendant phenyl ring has been synthesized using solid-phase parallel synthetic techniques. A key step in the synthesis of the library is a tandem alkylation cleavage in which diversity can be introduced at position 1 simultaneously to the cleavage from the resin. The yields of this step were significantly improved over what has previously been reported by addition of cesium carbonate to scavenge the acid that is formed during the reaction. Furthermore, we have shown that the solid support linkage is tolerant to Suzuki coupling and etherification reaction conditions and that selective cleavage of the linkage can take place in the presence of esters. The resulting 6-phenylquinolin-2(1H)-one library was screened against a panel of nuclear hormone receptors (androgen, estrogen alpha and beta isoforms, glucocorticoid, mineralocorticoid, and progesterone). Certain members of this library display moderate affinity for several of these receptors, and consequently, the 6-phenylquinolin-2(1H)-one core of the library may be considered a privileged structure for nuclear hormone receptors. In contrast, other members of the library display high selectivity for a particular receptor. The highest affinity ligand (9{2,1,1}) possesses an affinity of 330 nM for the androgen receptor, whereas the most selective ligand (9{2,4,1}) displays an affinity of 900 nM for the androgen receptor and a selectivity of 140-fold over the next highest affinity receptor.

  • 36. Shirani, Hamid
    et al.
    Stensland, Birgitta
    Bergman, Jan
    Södertörn University, School of Life Sciences.
    Janosik, Tomasz
    New routes to 3-(Arylthio)indoles: Application to the synthesis of the 3,3 '-bis(indolyl) sulfone core of the marine alkaloid echinosulfone A2006In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, no 15, p. 2459-2463Article in journal (Refereed)
    Abstract [en]

    A new approach to 3-(arylthio)indoles and related compounds has been developed, based on the reactions of aryl Grignard reagents or lithiated heteroaroinatics with a phenylsulfonyl-protected 3,3'-bis(indolyl) disulfide. In addition, a rational approach to the 3,3'-bis(indolyl) sulfone core of the alkaloid echinosulfone A has been accomplished, involving treatment of a 3-lithioindole with bis(phenylsulfonyl) sulfide as the key step.

  • 37. Sjögren, M
    et al.
    Göransson, U
    Johnson, Ann-Louise
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Dahlström, M
    Andersson, R
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Jonsson, P R
    Bohlin, L
    Antifouling activity of brominated cyclopeptides from the marine sponge Geodia barretti2004In: Journal of natural products (Print), ISSN 0163-3864, E-ISSN 1520-6025, Vol. 67, no 3, p. 368-372Article in journal (Refereed)
    Abstract [en]

    In this work, we show the potent antifouling effects of two compounds, barettin (cyclo[(6-bromo-8-entryptophan)arginine]) (1), isolated as a Z/E mixture (87/13), and 8,9-dihydrobarettin (cyclo[(6-bromotryptophan)arginine]) (2), isolated from the marine sponge Geodia barretti. The compounds were isolated guided by their ability to inhibit the settlement of cyprid larvae of the barnacle Balanus improvisus, and their structures were determined by means of mass spectrometry, NMR, and quantitative amino acid analysis. The activities of these brominated diketopiperazine-like cyclic dipeptides are in the range of antifouling agents in use today, as shown by their EC50 values of 0.9 and 7.9 muM, respectively. However, contrary to today's antifouling agents, the effects of barettin and 8,9-dihydrobarettin are nontoxic and reversible. A small set of synthetic analogues, including L-arginine, L-tryptophan, 5-bromo-D,L-tryptophan, 6-bromo-D,L-tryptophan, and 6-fluoro-D,L-tryptophan, were tested for possible structure-activity relationships. None of these compounds showed any effect at a concentration of 10 muM. We hypothesize that the isolated compounds are part of the sponge's chemical defense to deter fouling organisms. This theory is supported by the fact that barettin is found in water exposed to living specimens of G. barretti in concentrations that completely inhibit barnacles from settling.

  • 38.
    Slätt, Johnny
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Oxygenation of 2,3-dihydroindoles2002In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 58, no 45, p. 9187-9191Article in journal (Refereed)
    Abstract [en]

    Isatogens (3-oxo-3H-indole 1-oxides) possess interesting biological properties and development of a general method to construct these derivatives has now been developed. Indolines (2,3-dihydroindoles) and isatogens have been prepared in an efficient route starting from indoles substituted in position 2. Reduction of the 2-substituted indoles was performed with tin and hydrochloric acid to give racemic indolines, which were converted to isatogens by 3-chloroperoxybenzoic acid (m-CPBA).

  • 39.
    Slätt, Johnny
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Reinvestigation of a synthesis of quinoxaline-N-oxidesManuscript (preprint) (Other academic)
  • 40.
    Slätt, Johnny
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Beslic, Senad
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Stensland, Birgitta
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Intitutet.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Functionalizations of 3-(cyanoacetyl)indole and 2-(cyanoacetyl)pyrroleManuscript (preprint) (Other academic)
  • 41.
    Slätt, Johnny
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Janosik, Tomasz
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Wahlström, Niklas
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Synthetic applications of 3-(cyanoacetyl)indoles and related compounds2005In: Journal of Heterocyclic Chemistry, ISSN 0022-152X, E-ISSN 1943-5193, Vol. 42, no 1, p. 141-145Article in journal (Refereed)
    Abstract [en]

    Various synthetic applications of 3-(cyanoacetyl)indoles, as well as syntheses of some related indoles, have been investigated. Diethyl 2-(1H-indol-3-yl)-2-oxoethylphosphonate and a methyl derivative thereof have been prepared in one step from indole. Moreover, it was demonstrated that 3-(cyanoacetyl)indoles are useful starting materials for the preparation of for example 3-(1H-indol-3-yl)-3-oxopropanamides, 3-heteroarylindoles or 3-heteroaroylindoles.

  • 42.
    Slätt, Johnny
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Romero, Ivan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Cyanoacetylation of indoles, pyrroles and aromatic amines with the combination cyanoacetic acid and acetic anhydride2004In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 16, p. 2760-2765Article in journal (Refereed)
    Abstract [en]

    Cyanoacetic acid was activated with acetic anhydride and when heated this reagent reacted with a variety of both activated and deactivated pyrroles, indoles and aniline derivatives.

  • 43.
    Wahlström, Niklas
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Synthesis of 2,3 '-biindolyls and indolo[3,2-a]carbazoles2004In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, no 39, p. 7273-7275Article in journal (Refereed)
    Abstract [en]

    Several highly activated 2,3'-biindolyls were prepared from methyl 5,6-dimethoxyindole-2-carboxylate and oxindoles. The 2,3'-biindolyls were further transformed into a hydroxy indolo[3,2-a]carbazole and a bisindole amde.

  • 44.
    Wahlström, Niklas
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science.
    Romero, I
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Synthesis of metabolites of the Ah receptor ligand 6-formylindolo[3,2-b]carbazole2004In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 12, p. 2593-2602Article in journal (Refereed)
    Abstract [en]

    Synthesis of the five mono- and di-hydroxylated metabolites of the aryl hydrocarbon receptor high affinity ligand 6-formylindolo[3,2-b]carbazole is described. The structures of the metabolites were unequivocally established as 2-hydroxy-, 8-hydroxy-, 2,10-dihydroxy-, 4,8-dihydroxy- and 2,8-dihydroxyindolo[3,2-b]carbazole-6-carboxaldehyde.

  • 45.
    Wahlström, Niklas
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Stensland, B
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Synthesis of 2,3 '-diindolylmethanes and substituted indolo[3,2-b]carbazoles2004In: Synthesis (Stuttgart), ISSN 0039-7881, E-ISSN 1437-210X, no 8, p. 1187-1194Article in journal (Refereed)
    Abstract [en]

    Three different synthetic routes to substituted 2,3'-diindolylmethanes, and the syntheses of substituted indolo[3,2-b]carbazoles are described. The first rigid proof of an acylation in the 2-position of a 1,3-unsubstituted indole is also presented in the form of an X-ray structure.

  • 46.
    Wahlström, Niklas
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Stensland, B
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Synthesis of the marine alkaloid caulersin2004In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 60, no 9, p. 2147-2153Article in journal (Refereed)
    Abstract [en]

    A three-step synthesis of caulersin (3) from indole-2-acetic acid methyl ester and indole-2-carbonyl chloride is described. As the spectral data of the synthetic sample differed from those reported for the natural product, the structure was determined by X-ray crystallography.

  • 47.
    Wiklund, Per
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institute.
    Alkylation and acylation of basic salts of anthranilic acid2004In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 45, no 5, p. 969-972Article in journal (Refereed)
    Abstract [en]

    The O-nucleophilicity of basic anthranilic acid salts was documented, analyzed, and utilized in synthesis. Specifically substitutions leading to esters instead of secondary amines, and formation of anthranilic acid anhydrides were studied.

  • 48.
    Wiklund, Per
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institutet.
    Ring forming reactions of imines of 2-aminobenzaldehyde and related compounds2003In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 1, no 2, p. 367-372Article in journal (Refereed)
  • 49.
    Wiklund, Per
    et al.
    Södertörn University, School of Life Sciences.
    Bergman, Jan
    Södertörn University, School of Life Sciences.
    The chemistry of anthranilic acid2006In: CURRENT ORGANIC SYNTHESIS, ISSN 1570-1794, Vol. 3, no 3, p. 379-402Article in journal (Refereed)
    Abstract [en]

    Anthranilic acid (2-aminobenzoic acid, AA) is a versatile and low cost starting material for synthesis of benzofused heterocycles. It also plays a vital part in the biosynthesis of tryptophan and its derivatives, as well as in several types of alkaloids. Therefore the chemistry of anthranilic acid is of importance in medicinal and biological chemistry. The main emphasis of this review article is on the use of anthranilic acid as a starting material for synthesis of heterocycles, but it also covers the history, synthesis and reactivity, as well as a short account of the medicinal chemistry and biochemistry of anthranilic acids.

  • 50.
    Wiklund, Per
    et al.
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Rogers-Evans, M
    F. Hoffmann-La Roche Ltd, Basel, Switzerland .
    Bergman, Jan
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Synthesis of 1,4-benzodiazepine-3,5-diones2004In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 69, no 19, p. 6371-6376Article in journal (Refereed)
    Abstract [en]

    Even though benzodiazepines have a strong position in medicinal chemistry, very few synthetic routes to 1H-1,4-benzodiazepine-3,5(2H,4H)-diones have ever been published and the claimed products have often been poorly characterized. Through the present work several 1H-1,4-benzodiazepine-3,5(2H,4H)-diones have become available from N-carbamoylmethylanthranilic acids. The required ring closures were achieved only when the amino groups of the starting materials were substituted with electron withdrawing groups such as acetyl, alkyloxycarbonyl, or nitroso. During the synthetic work a novel ring contraction rearrangement from a 1-nitroso-1H-1,4-benzodiazepine-3,5(2H,4H)-dione to a 3H-quinazoline-4-one was observed. The proposed mechanism involves elimination of HNO followed by a proton-mediated loss of CO. The 1-nitrosated 1,4-benzodiazepinediones could be separately denitrosated to the corresponding amino compounds.

12 1 - 50 of 57
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