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  • 1. Aeluri, Madhu
    et al.
    Pramanik, Chinmoy
    Chetia, Lakshindra
    Mallurwar, Naveen Kumar
    Balasubramanian, Sridhar
    Chandrasekar, Gayathri
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies.
    Kitambi, Satish Srinivas
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies. Karolinska Institute.
    Arya, Prabhat
    14-Membered Macrocyclic Ring-Derived Toolbox: The Identification of Small Molecule Inhibitors of Angiogenesis and Early Embryo Development in Zebrafish Assay2013In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 15, no 3, p. 436-439Article in journal (Other academic)
    Abstract [en]

    A highly practical and modular synthesis to obtain a diverse 14-membered ring-based macrocyclic toolbox is achieved. These compounds were further tested in zebrafish assays related to early embryonic development, angiogenesis, and neurogenesis, respectively. 1.4c was Identified as an antiangiogenesis agent.

  • 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, 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)
  • 6.
    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.

  • 7.
    Björk, Malin
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Synthesis of sulfur and seleniumn heterocycles, including derivatives of imidazopyridine and benzimidazole2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The chemistry developed in this thesis can be divided into two parts. The first part, which is the major part of the thesis, contains syntheses towards analogues to mutagenic heterocyclic amines found in e.g. meat fried at high temperatures. The second part concentrates on the palladium-(0)catalyzed cross-coupling reactions of 4- and 5-substituted 2,1,3-benzoselenadiazoles. The heterocyclic amines described can be divided into the linear and the angular compounds. Five linear imidazo[4,5-b]pyridines were synthesised via the Friedländer reaction: 2-amino-1 - methylbenzothieno[2,3-e]imidazo[4,5-b]pyridine, 2-amino-1-methy-benzothieno [3,2-e] imidazo[4,5-b] pyridine, 2-amino-1-methylthieno[2,3-elimidazo[4,5-b]-pyridine, 2-amino-1methylthieno[3,2-e]imidazo[4,5-b]pyridine and the sulfur analogue to the cooked-food mutagen IFP, 2-amino- 1,6-dimethylthieno[2,3-e]imidazo[4,5-b]pyridine. Attempts were made to form three thienoimidazo[4,5-b]pyridines via stepwise condensation. The first condensation between creatinine and 2-nitro-3-thiophene-carbaldehyde, 3-amino-2thiophenecarbaldehyde and 4-azido3-thiophenecarbaldehyde yielded thenylidenomethyleneimidazolinones, but only one of these gave the ring closed compound 2-amino-1-methylthieno[2,3-e]imidazo[4,5-b]pyridine by a second condensation. In addition, 2-amino- 1 methyl benzoth ieno[3,2-e] imidazo[4,5 -b] pyridine was transformed into the 2-nitro- and 2-hydroxy derivative. The last linear isomer 2-amino-1methylimidazo[4,5-b]benzothiophene, was synthesized by a different route. The series of angular compounds are considered analogues to the food-mutagen IQx. A series of six homologues of 7-amino-imidazo[4,5-e]-2,1,3-benzoselenadiazoles. Four ring systems were obtained by treating 4-methylamino-3-nitro-phenylenedianmine with a range of biselectrophiles, namely: 2-amino-1-methylbenzo-thiadiazole, -triazole, -diazepinone and 2amino1 -methylimidazobenzimidazole. Among the palladium-(0)-catalyzed cros s- couplings, the Suzuki, Stille, Fleck and Sonogashira reactions were used. These were applied to 4-, or 5-bromo-2,1,3-benzoselenadiazoles. In addition, the 4- and 5-trimethyltin-2,1,3-benzoselenadiazole were synthesized.

  • 8.
    Björk, Malin
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Grivas, Spiros
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Classical conditions of Suzuki, Stille, Heck and Sonogashira couplings applied on 4- and 5-substituted 2,1,3-benzoselenadiazolesManuscript (preprint) (Other academic)
  • 9.
    Björk, Malin
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Grivas, Spiros
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Synthesis of imidazo[4,5-e]-2,1,3-benzoselenadiazoles and derivatives thereofManuscript (preprint) (Other academic)
  • 10.
    Björk, Malin
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Grivas, Spiros
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Synthesis of novel 2-aminoimidazo[4,5-b]pyridines, including the thieno analogue of the cooked-food mutagen IFP2006In: Journal of Heterocyclic Chemistry, ISSN 0022-152X, E-ISSN 1943-5193, Vol. 43, no 1, p. 101-109Article in journal (Refereed)
    Abstract [en]

    Eight new compounds, including three new ring systems obtained via the Friedlander condensation of ortho-aminothiophenecarbaldehydes 11, 21 and 24 with creatinine (8), are reported. The condensation afforded 1, which is the thieno analogue of the cooked-food mutagen IFP (2-amino-1,6-dimethylfuro[2,3-e]imidazo[4,5-b]pyridine), and the benzothieno[2,3-e]- and benzothieno[3,2-e]imidazo[4,5-b]pyridines 2 and 3. Attempts to condense 11 with isocreatinine (12) were unsuccessful. Desulfurization of 3 gave the known cooked-food carcinogen PhIP. The 2-nitro (4) and 2-hydroxy (5) derivatives of 3 are reported. The related 2-amino-1-methyl-imidazo[4,5-b]benzothiophene (25) was synthesized by a different route. Fully assigned H-1 and C-13 nmr data of all new compounds are reported.

  • 11.
    Björk, Malin
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Grivas, Spiros
    Södertörn University, School of Life Sciences. Karolinska Institutet.
    Synthesis of thienoimidazo[4,5-b]pyridines and thenylidenoimidazolinones2005In: Heterocycles, ISSN 0385-5414, E-ISSN 1881-0942, Vol. 65, no 10, p. 2369-2380Article in journal (Refereed)
    Abstract [en]

    The two isomers 2-amino-1-methylimidazo[4,5-b]thieno[3,2-e]pyridine (3) and 2-amino-1-methylimidazo[4,5-b]thieno[2,3-e]pyridine (4) were synthesized by the Friedlander reaction starting from creatinine and the appropriate aminothiophenecarbaldehydes (11 and 13). Creatinine was also condensed with 2-nitro-3-thiophenecarbaldehyde (10) in ethylene glycol to yield the 2-amino-1-methyl-5-[2-(2-nitro-3-thenylidene)]-2-imidazolin-4-one (7a), with 3-amino-2-thiophenecarbaldehyde (13) under Perkin conditions to yield 2-acetamido-5-[2-(3-acetamido-2-thenylidene)]-1-methyl-2-imidazolin-4-on e (8), and with 4-azido-3-thiophenecarbaldehyde (17) in acetic acid to yield 2-amino-5[2-(4-azido-3-thenylidene)]-1-methyl-2-imidazolin-4-one (9). The thenylidenoimidazolinonc (8) was converted into compound (4).

  • 12. Dasari, Bhanudas
    et al.
    Jogula, Srinivas
    Borhade, Ramdas
    Balasubramanian, Sridhar
    Chandrasekar, Gayathri
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies.
    Kitambi, Satish Srinivas
    Södertörn University, School of Natural Sciences, Technology and Environmental Studies. Karolinska Institute.
    Arya, Prabhat
    Macrocyclic Glycohybrid Toolbox Identifies Novel Antiangiogenesis Agents from Zebrafish Assay2013In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 15, no 3, p. 432-435Article in journal (Other academic)
    Abstract [en]

    A practical and modular approach to obtain a diverse set of 14-membered macrocyclic compounds from carbohydrates is developed that utilizes functional groups at C-1 and C-5. The evaluation of this toolbox in various zebrafish assays led to the identification of 2.7f as an antianglogenesis agent.

  • 13.
    Engqvist, Robert
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Syntheses of some tri- and tetracyclic heterocycles containing an indole moiety2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with the development of new synthetic methods leading to fused tri- and tetracyclic heterocycles, many of which have interesting biological activity such as antiviral and DNA intercalating properties. The reactions between isatins and 2-aminobenzylamine in acetic acid can give, depending on the conditions, either complex spirooxindoles or indolo[3,2-c]quinolin-6-ones. Proposed mechanisms are presented (involving a simpler form of spirooxindoles). These spirooxindoles can easily be obtained from isatins and 2-aminobenzylamine in methanol (Paper I). The previously unknown, but incorrectly claimed, linear isomer of indolo[3,2-c]quinolin-6one, i.e. indolo[2,3-b]quinolin-11-one, has been prepared for the first time by thermal (260 degrees C) cyclization of methyl 2 -phenylamino-indole-3 -carboxylate, which was in turn prepared in two steps from methyl indole-3 -carboxylate. The benzothiopyrano[2,3-b]indol-11-one and benzopyrano[2,3-b]indol-11-one could be prepared similarly (Papers I and II). Suitable 2-chloro-3-formylindoles have been used for the preparation of the alkaloids neocryptolepine, thienodolin and derivatives thereof (Papers III and IV). Finally, synthetic work towards potential metabolites of the lead compound B-220 is presented. We have described a method for reduction of the biologically interesting indolo[2,3b)quinoxalines with zinc, which are subsequently trapped with an appropriate anhydride to provide the corresponding mono or diacylated 5,1 1-dihydroindolo[2,3b]quinoxalines in good yields (paper V). Synthesis of hydroxy derivatives of B-220 can be effected from the appropriate methoxyisatins. Futher derivatives like the vinyl-, Nmethylaminoethyl- and Noxido derivatives of B-220 have also been synthesised.

  • 14.
    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)
  • 15.
    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.

  • 16.
    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.

  • 17.
    Grivas, Spiros
    Södertörn University, Avdelning Naturvetenskap.
    2,1,3-benzoselenadiazoles as valuable synthetic intermediates2000In: Current organic chemistry, ISSN 1385-2728, E-ISSN 1875-5348, Vol. 4, no 7, p. 707-726Article in journal (Refereed)
    Abstract [en]

    N-alkyl-1,2-benzenediamines, 4-substituted-3-nitro-1,2-benzenediamines and 3,4-diamino-2-nitrophenols are readily obtained by deselenation of alkyl quaternary salts of 2,1,3-benzoselenadiazoles (bsd) and 5-substituted-4-nitro-bsd. The latter are easily obtained by nitration of 5-X-bsd (X = Me, Br, Cl, F, OMe, NHMe). Nitration of 5-fluoro-bsd yields the 4-nitro derivatives that are accompanied by substantial amounts of the corresponding 4-nitro-bsd-5-ols. ipso-Nitration of 5-fluoro-4-methyl-bsd is followed by instantaneous hydrolysis to (+/-)-4-methyl-4-nitro-bsd-5(4H)-one. Batcho-Leimgruber indole synthesis on 5-methyl-4-nitro-bsd followed by reductive deselenation of 1,2,5-selenadiazolo[3,4-g]indole affords 6,7-diaminoindole. Cyclocondensation of 3-nitro-1,2-benzenediamines with acetylacetone provides a convenient route for the preparation of 2-methyl-4-nitrobenzimidazoles. Less-accessible 6-halo-5-nitro- and 6-methoxy-5-nitroquinoxalines are efficiently synthesized by regioselective condensation of alpha-dicarbonyls with 4-halo- and 4-methoxy-3-nitro-1,2-benzenediamines. The reactive halogen atom or methoxyl group ortho to the nitro substituent renders these quinoxalines versatile intermediates to further heterocycles. The Se-77, C-13 and H-1 NMR chemical shifts of sixteen bsd derivatives, and the C-13 NMR chemical shifts of eight derivatives of 2-methylquinoxalines are presented.

  • 18. 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.

  • 19.
    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.

  • 20.
    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.

  • 21. 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.

  • 22.
    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.

  • 23. 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.

  • 24. 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.

  • 25. 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.

  • 26.
    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.

  • 27. 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)
  • 28. Okwakol, J
    et al.
    Grivas, Spiros
    Södertörn University, School of Life Sciences.
    5H-[1,2,5]selenadiazolo[3,4-f]indole as a masked form of 5,6-diaminoindole2005In: Heterocycles, ISSN 0385-5414, E-ISSN 1881-0942, Vol. 65, no 8, p. 1939-1946Article in journal (Refereed)
    Abstract [en]

    6-Nitroindoline (9) was converted into 1-acetyl-5,6-aminoindoline (12) which was then transformed via selenadiazoles (13-15) to the title selenadiazoloindole (4) by two alternative 3-step synthetic sequences in 38-.42% overall yield from 12. The unstable 5,6-diaminoindole (16) was then obtained by reductive deselenation of 4. Fully assigned H-1, C-13 and Se-17 NMR spectral data for the title indole (4) and Se-77 NMR spectral data for the intermediate selenadiazoles (13-15) are presented.

  • 29.
    Okwakol, Jealux
    et al.
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Grivas, Spiros
    Södertörn University, School of Life Sciences. Karolinska Institute.
    Synthesis of thienoindoles via the vicarious nucleophilic substitution of nitrobenzo[b]thiopenes2006In: Heterocyclic Communications, ISSN 0793-0283, E-ISSN 2191-0197, Vol. 12, no 3-4, p. 173-178Article in journal (Refereed)
    Abstract [en]

    The 8H-thieno[3,2-g]indole (12) and 6H-thieno[3,2-e]indole (16) were easily obtained by the reductive cyclisation of (5-amino-1-benzothien-4-yl)acetonitrile (15) and (7-amino-1-benzothien-6-yl)acetonitrile (11), the latter synthesised via cyanomethylation of 5- and 7-nitrobenzo[b]thiophienes.

  • 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. 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.

  • 35.
    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.

  • 36.
    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.

  • 37. Tinnert, A S
    et al.
    Månsson, Martin
    Södertörn University, School of Life Sciences.
    Yildirim, Håkan H
    Södertörn University, School of Life Sciences.
    Hood, D W
    Schweda, Elke K H
    Södertörn University, School of Life Sciences.
    Structural investigation of lipopolysaccharides from nontypeable Haemophilus influenzae: investigation of inner-core phosphoethanolamine addition in NTHi strain 9812005In: Carbohydrate Research, ISSN 0008-6215, E-ISSN 1873-426X, Vol. 340, no 11, p. 1900-1907Article in journal (Refereed)
    Abstract [en]

    LPS of NTHi comprises a conserved tri-L-glycero-D-manno-heptosyl inner-core moiety (L-alpha-D-Hepp-(1 -> 2)-[PEtn -> 6]-L-alpha-D-Hepp-(1 -> 3)-[beta-D-Glcp-(1 -> 4)]-L-alpha-D-Hepp-(1 -> 5)-alpha-Kdop) in which addition of PEtn to the central heptose (HepII) in strain Rd is controlled by the gene lpt6. It was recently shown that NTHi strain 981 contains an additional PEtn linked to O-3 of the terminal heptose of the inner-core moiety (HepIII). In order to establish whether lpt6 is also involved in adding PEtn to HepIII, lpt6 in strain 981 was inactivated. The structure of the LPS of the resulting mutant strain 981lpt6 was investigated by MS and NMR techniques by which it was confirmed that the lpt6 gene product is responsible for addition of PEtn to O-6 of HepII in strain 981. However, it is not responsible for adding PEtn to O-3 of HepIII since the 981lpt6 mutant still had full substitution with PEtn at HepIII

  • 38.
    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.

  • 39.
    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.

  • 40.
    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.

  • 41.
    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.

  • 42.
    Wiklund, Per
    Södertörn University, School of Chemistry, Biology, Geography and Environmental Science. Karolinska Institutet.
    Synthesis of heterocycles from anthranilic acid and its derivatives2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Anthranilic acid (2-aminobenzoic acid, Aa) is the biochemical precursor to the amino acid tryptophan, as well as a catabolic product of tryptophan in animals. It is also integrated into many alkaloids isolated from plants. Aa is produced industrially for production of dyestuffs and pharmaceuticals. The dissertation gives a historical background and a short review on the reactivity of Aa. The synthesis of several types of nitrogen heterocycles from Aa is discussed. Treatment of anthranilonitrile (2-aminobenzonitrile, a derivative of Aa) with organomagnesium compounds gave deprotonation and addition to the nitrile triple bond to form amine-imine complexed dianions. Capture of these intermediate with acyl halides normally gave aromatic quinazolines, a type of heterocyclic compounds that is considered to be highly interesting as scaffolds for development of new drugs. When the acyl halide was a tertiary 2-haloacyl halide, the reaction instead gave 1,4-benzodiazepine-3-ones via rearrangement. These compounds are isomeric to the common benzodiazepine drugs (such as diazepam, Valium®) which are 1,4-benzodiazepine-2-ones. Capture of the dianions with aldehydes or ketones, led to 1,2-dihydroquinazolines. Unsubstituted imine anions could be formed by treatment of anthranilonitrile with diisobutylaluminium hydride. Also in this case capture with aldehydes gave 1,2-dihydroquinazolines. Several different dicarboxylic acid derivatives of Aa were treated with dehydrating reagents, and the resulting products were more or less complex 1,3-benzoxazinones, one of which required X-ray crystallography confirm its structure. During the work on preparation of N-substituted derivatives of Aa, necessary for synthesis of 1,4-benzodiazepine-3,5-diones, it was noted that many of the obtained products were in fact not N-substituted, but O-substituted. This challenged the established notion that Aa reacts nucleophilically at the N-terminal under most conditions. Several grave errors in the recent literature were revealed. In 1976 researchers from the group that originally developed the common benzodiazepine drugs published a retraction of a claim of synthesis of a benzodiazepine by Gärtner in 1904. They found that the method actually gave a 6-membered ring system, not a 7-membered 1,4-benzodiazepine-3,5-dione as originally claimed. Because the 1,4-benzodiazepine skeleton is highly interesting as a scaffold for development of new drugs, a few publications on synthesis of this target has appeared. However, repetition of several of the described syntheses failed to yield the poorly described products. Studies on how to ring close N-carbamoyl derivatives of Aa were undertaken. It became clear that Umpolung of the substrates by N-derivatisation was a necessary prerequisite for ring closure. The introduction of the N-nitroso group was developed to this end, leading to N1-nitroso substituted 1,4-benzodiazepine-3,5-diones. The nitroso group could be removed after ring closure. Heating of one of these compounds induced a ring contraction rearrangement. A proposed mechanism involves elimination of HNO (nitrosyl) and proton mediated loss of CO.

  • 43.
    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.

  • 44.
    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)
  • 45.
    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.

  • 46.
    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.

  • 47.
    Wiklund, Per
    et al.
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Romero, Ivan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Products from dehydration of dicarboxylic acids derived from anthranilic acid2003In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 1, no 19, p. 3396-3403Article in journal (Refereed)
  • 48. Witt, A
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Recent developments in the field of quinazoline chemistry2003In: Current organic chemistry, ISSN 1385-2728, E-ISSN 1875-5348, Vol. 7, no 7, p. 659-677Article in journal (Refereed)
    Abstract [en]

    Recent developments in the chemistry of quinazolines and quinazolinones are discussed. The chemistry of quinazoline alkaloids is reviewed featuring chrysogine, luotonin A, tryptanthrin, febrifugine. and rutaecarpine.

  • 49. Witt, A
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap.
    Synthesis and reactions of some 2-vinyl-3H-quinazolin-4-ones2000In: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 56, no 37, p. 7245-7253Article in journal (Refereed)
    Abstract [en]

    A simple, high-yielding synthesis of 2-vinyl-3H-quinazolin-4-one, 2-(1-chlorovinyl)-3H-quinazolin-4-one and 2-(1-bromovinyl)-3H-quinazolin-4-one. The 2-vinylquinazolinones 11a and 14 participate readily in nucleophilic addition reactions. Treatment with both carbon and nitrogen nucleophiles results in a clean conversion into a variety of 2-substituted 3H-quinazolin-4-one derivatives. The 2-(1-halovinyl)-3H-quinazolin-4-ones 11b and Ile reacted with carbon nucleophiles to give several derivatives of 2-substituted 3H-quinazolin-4-one, such as dihydrofurancarboxylic ethyl ester 23.

  • 50. Witt, A
    et al.
    Bergman, Jan
    Södertörn University, Avdelning Naturvetenskap. Karolinska Institute.
    Total syntheses of the benzodiazepine alkaloids circumdatin F and circumdatin C2001In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 66, no 8, p. 2784-2788Article in journal (Refereed)
    Abstract [en]

    Total syntheses of circumdatin F and circumdatin C, which both possess a 3H-quinazolin-4-one as well as a 1,4-benzodiazepin-5-one moiety, are described. A tripeptide derivative was synthesized as a key intermediate and dehydrated to a benzoxazine by reaction with triphenylphosphine, iodine, and a tertiary amine. The natural products were attained via rearrangements to an amidine intermediate, deprotection with 45% HBr in acetic acid, and cyclization on silica gel.

12 1 - 50 of 52
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