SwePub - sökning: L773:0040 4020

Numrering	Referens	Omslagsbild	Hitta
1.	Bergman, Jan, et al. (författare) Studies of the reactions between indole-2,3-diones (isatins) and 2-aminobenzylamine 2003 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 59:7, s. 1033-1048 Tidskriftsartikel (refereegranskat)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.
2.	Daferner, M, et al. (författare) Zopfiellamides A and B, antimicrobial pyrrolidinone derivatives from the marine fungus Zopfiella latipes 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:39, s. 7781-7784 Tidskriftsartikel (refereegranskat)abstract Two new antimicrobial metabolites, zopfiellamides A (1) and B (2) were isolated from fermentations of the facultative marine fungus Zopfiella latipes CBS 611.97. Their structures were elucidated by spectroscopic techniques, and they are pyrrolidinone derivatives. (C) 2002 Elsevier Science Ltd. All rights reserved.
3.	Ek, Fredrik, et al. (författare) Synthesis of Fused Tertazole- and Imidazole Derivatives via Iodocyclization. 2003 Ingår i: Tetrahedron. - 0040-4020. ; 59:35, s. 6759-6769 Tidskriftsartikel (refereegranskat)abstract The possibility to prepare fused tetrazole- and imidazole derivatives by iodocyclization in moderate to excellent yields is demonstrated. In some examples the cyclizations were not following Baldwin's rules entirely, i.e. exo-selectivity. Nucleophilic substitution of the formed iodides gave different results depending on the hardness of the nucleophile. Thus, elimination of the iodide could be a problem but a substitution reaction with ethyl potassium xanthate and a radical reaction using acrylonitrile were tolerated. In addition, we showed that it is possible to selectively use three iodo substituents individually in one of the fused imidazole derivatives.
4.	Hedenström, Erik, et al. (författare) Sex Pheromone of pine sawflies. Chiral syntheses of some active minor components isolated from neodiprion sertifer and of some chiral analogues of diprionyl acetate. 1992 Ingår i: Tetrahedron. - 0040-4020. ; 48:15, s. 3139-3146 Tidskriftsartikel (refereegranskat)abstract The chiral syntheses of some analogues, 2 - 7, of 3,7-dimethyl-2-pentadecanol, 1 (diprionol), and of the corresponding acetates are described. The acetate of 1 is the main attractant in the sex pheromone of the Neodiprion genus (Diprionidae). Compounds 2 /2- 4 were identified as minor components isolated from females of Neodiprion sertifer. Synthetic intermediates were prepared either from chiral starting materials, via asymmetric syntheses, or by baker's yeast reductions.
5.	Johansson, Martin H, et al. (författare) Synthesis of (-)-pregaliellalactone, conversion of (-)-pregaliellalactone to (-)-galiellalactone by mycelia of Galiella rufa 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:13, s. 2523-2528 Tidskriftsartikel (refereegranskat)abstract An enantioselective synthesis of (-)-pregaliellalactone (1), a biosynthetic precursor of the potent fungal metabolite ( -)-galiellalactone (3) produced by several ascomycetes, is reported. When fed to a culture of Galiella rufa, 1 was efficiently converted to 3. (C) 2002 Elsevier Science Ltd. All rights reserved.
6.	Kahnberg, Pia, et al. (författare) Alternative routes to pterulone 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:26, s. 5203-5208 Tidskriftsartikel (refereegranskat)abstract Two new synthetic routes to pterulone, a fungal metabolite possessing potent antifungal activity as an inhibitor of NADH/ubiquinone oxidoreductase, are reported. (C) 2002 Elsevier Science Ltd. All rights reserved.
7.	Leclercq, Sabine, et al. (författare) Furanocembranoid Diterpenes as Defensive Compounds in the Dufour Gland of the Ant Crematogaster brevispinosa rochai 2000 Ingår i: Tetrahedron. - 0040-4020. ; 56:14, s. 2037-2042 Tidskriftsartikel (refereegranskat)abstract Two new furanocembranoid diterpenes, crematofuran [(1R∗,11R∗,12R∗)-6,19:11,12-bisepoxycembra-3,6,8(19),15-tetraene] (1) and isocrematofuran [(1R∗,3S∗,4S∗)-3,4:6,19-bisepoxycembra-6,8(19),11,15-tetraene] (2), have been isolated from the Dufour gland secretion of the Brazilian ant Crematogaster brevispinosa rochai. Their structures, including the relative configuration, have been determined by a combination of NMR and molecular mechanics methods. The toxicity of 1 towards other ants is on the same level as that of nicotine. This is the first report of cembranoid diterpenes as defensive compounds in an ant.
8.	Maricic, Suzana, et al. (författare) Synthesis and conformational studies of a Leu-enkephalin amide analogue containing a ferrocene substructure 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:15, s. 3085-3093 Tidskriftsartikel (refereegranskat)abstract Solution phase synthesis of a constrained Leu(5)-enkephalin amide analogue 10 is reported, in which the cyclic ferrocenyl containing subunit 7 was introduced as a mimetic of the tetrapeptide Tyr-Gly-Gly-Phe unit. Temperature dependence of the chemical shift of the amide protons of 10 indicated a hydrogen bond between the same amino acid residues as observed for the natural Leu-enkepalin in the single-bend conformation. The rotational barrier (DeltaG(c)(not equal)=16.8 kcal/mol) of the C-terminal amide group, which was determined by DNMR spectroscopy, and NOESY experiments indicated that the two termini were more distant as compared to the single-bend conformation of natural Leu-enkephalin amide. (C) 2002 Elsevier Science Ltd. All rights reserved.
9.	Olsson, Roger, et al. (författare) Endocyclic cleavage of glycosides. VI. Substituent effects of the alkylative endocyclic cleavage of glycosides 1998 Ingår i: Tetrahedron. - 0040-4020. ; 54:15, s. 3935-3954 Tidskriftsartikel (refereegranskat)abstract A number of pentopyranoside derivatives were treated with Me 3 Al in order to investigate the influence of structural parameters on the methyl group transfer in the endocyclic alkylative cleavage reaction of these substrates. A cyclic CH ··· O hydrogen bonded model is suggested as an intermediate, which is used to explain the stereoselectivities for different substrates. In several, cases the diastereoselectivities were better than 9:1.
10.	Rasser, F, et al. (författare) Terpenoids from Bovista sp 96042 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:39, s. 7785-7789 Tidskriftsartikel (refereegranskat)abstract The novel cytotoxic hexacyclic illudane-illudalane bis-sesquiterpene bovistol (la) was obtained from the basidiomycete Bovista sp. 96042, together with several new sesquiterpenes. la is formed in the fungus by a heteroatom Diels-Alder dimerisation of psathyrellon B (2). (C) 2002 Elsevier Science Ltd. All rights reserved.
11.	Somfai, Peter, et al. (författare) An enantiospecific synthesis of D-erythro-sphingosine from D-tartaric acid 1993 Ingår i: Tetrahedron. - 0040-4020. ; 49:30, s. 6645-6650 Tidskriftsartikel (refereegranskat)abstract An efficient enantiospecific synthesis of D-erythro-sphingosine (1) via azidosphingosine (2) is described, the absolute stereochemistry being derived from D-tartaric acid.
12.	Sundin, Anders, et al. (författare) The structure determination of panellon and panellol, two 14-noreudesmanes isolated from Resupinatus leightonii 1993 Ingår i: Tetrahedron. - 0040-4020. ; 49:34, s. 7519-7524 Tidskriftsartikel (refereegranskat)abstract The structures of two fungal norsesquiterpenes containing a diepoxide functionality, isolated from cultures of the basidiomycete Resupinatus leightonii, were elucidated by a combination of X-ray analysis, NMR spectroscopy and molecular mechanics calculations.
13.	Tsirk, Anders, et al. (författare) Synthesis of Substituted Benzo[b]indolizidines and Benzo[b]quinolizidines via Ring-Opening of 3-Bromo-2,5-dimethylthiophene-1,1-dioxide 1997 Ingår i: Tetrahedron. - 0040-4020. ; 53:2, s. 771-784 Tidskriftsartikel (refereegranskat)abstract A new method for the preparation of benzo[b]indolizidines and benzo[b]quinolizidines based on two reactions: an amine induced ring-opening of 3-bromo-2,5-dimethylthiophene-1,1-dioxide (1) with 2-allyl-pyrrolidine (2), 2-allylpiperidine (3), 2-[2-(1',3'-dithiolan)methyl]pyrrolidine (4) and 2-[2-(1'-3'-dithiolan)methyl]piperidine (5); and an intramolecular Diels-Alder reaction, is described. Copyright (C) 1996 Elsevier Science Ltd
14.	Tsirk, Anders, et al. (författare) Synthesis of Substituted Thiophene-1,1-Dioxides and their Ring-Opening Reactions with w-Unsaturated Secondary Amines; a Synthetic Route to Azatrienes. 1995 Ingår i: Tetrahedron. - 0040-4020. ; 51:25, s. 7035-7044 Tidskriftsartikel (refereegranskat)abstract The scope and limitations of the ring-opening of thiophene dioxides upon reaction with cyclic secondary amines, leading to dialkylaminomethyl substituted halobutadienes has been further studied. Using ω-unsaturated acyclic secondary amines trienes could be prepared by this methodology.
15.	Tsopmo, Apollinaire, et al. (författare) A norbislabdane and other labdanes from Aframomum sulcatum 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:14, s. 2725-2728 Tidskriftsartikel (refereegranskat)abstract Extracts of the seeds of Aframomum sulcatum (Oliv. & Hanb) K. Schum (Zingiberaceae) yielded a novel norbislabdane derivative, sulcanal (1) and the new labdane (12E)-8beta,17-epoxy-11-hydroxy-12-labden-15.16-dial-11,15-hemiacetal (2) (as a 1:1 C-15 epimeric mixture), along with known labdane diterpenes.
16.	Baeckstrom, P., et al. (författare) Synthesis and characterization of all four isomers of methyl 2,4-decadienoate for an investigation of the pheromone components of Pityogenes chaicographus 1988 Ingår i: Tetrahedron. - : Elsevier. - 0040-4020 .- 1464-5416. ; 44:9, s. 2541-2548 Tidskriftsartikel (refereegranskat)
17.	BERGMAN, J, et al. (författare) 2,2'-BIINDOLYL REVISITED - SYNTHESIS AND REACTIONS 1995 Ingår i: TETRAHEDRON. - 0040-4020. ; 51:19, s. 5631-5642 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
18.	Bergman, J, et al. (författare) Cyclization of N-acylanthranilic acids with Vilsmeier reagents. Chemical and structural studies 1996 Ingår i: TETRAHEDRON. - : Elsevier BV. - 0040-4020. ; 52:3, s. 753-770 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
19.	Bergman, Jan, et al. (författare) 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 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 56:13, s. 1911-1916 Tidskriftsartikel (refereegranskat)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.
20.	Bergman, J, et al. (författare) Syntheses of gem-dinitro heterocyclic compounds, their ring-opening reactions and transformations into indoles, indazoles and benzoxazinones 1999 Ingår i: TETRAHEDRON. - 0040-4020. ; 55:34, s. 10447-10466 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
21.	Bergman, J, et al. (författare) Synthesis and reactions of some dinitrodiazoquinones 1999 Ingår i: TETRAHEDRON. - 0040-4020. ; 55:17, s. 5581-5592 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
22.	Bergman, Jan, et al. (författare) 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 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:45, s. 9179-9185 Tidskriftsartikel (refereegranskat)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.
23.	Bergman, Jan, et al. (författare) Synthesis of cyclopent[b]indolones 1990 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 46:17, s. 6067-6084 Tidskriftsartikel (refereegranskat)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.
24.	Bergman, J, et al. (författare) Synthesis of indolo[3,2-a]pyrrolo[3,4-c]carbazole in one step from indole and maleimide 1999 Ingår i: TETRAHEDRON. - 0040-4020. ; 55:8, s. 2363-2370 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
25.	Bergman, Jan, et al. (författare) Synthesis of indolocarbazole quinones; potent aryl hydrocarbon receptor ligands 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:7, s. 1443-1452 Tidskriftsartikel (refereegranskat)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.
26.	Garg, Neeraj, et al. (författare) 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 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 52:48, s. 15209-15224 Tidskriftsartikel (refereegranskat)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.
27.	Gogoll, Adolf, 1957-, et al. (författare) Reaction of pyridine derivatives with butyl glycidyl ether as a model system for glycidyl ether modified agarose : structural assignment by selective inept spectra 1990 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 46:7, s. 2539-2548 Tidskriftsartikel (refereegranskat)abstract The reaction of 2-thio-pyridine N-oxide, 2-amino-, 2-hydroxy, 2-thio-, and 4-thiopyridine with butyl glycidyl ether was investigated as a model system for the functionalization of 2,3-epoxypropyl activated agarose. Unambiguous structural assignment of the products was provided by selective INEPT and nuclear Overhauser difference spectra. All reactions were shown to give only one of the possible regioisomers. Further conclusions regarding the structure of the agarose derivatives were drawn from IR spectra.
28.	Hedenström, Erik, et al. (författare) Efficient Opening of trans-2,3-Epoxybutane by a Higher Order Cuprate : Synthesis of erythro-3.7-Dimethylpentadecan-2-yl Acetate, Pheromone of Pine Sawflies 1994 Ingår i: Tetrahedron. - 0040-4020. ; 50:17, s. 5225-5232 Tidskriftsartikel (refereegranskat)
29.	Högberg, Hans-Erik, et al. (författare) Synthesis and Gas Chromatographic Separation of the eight Stereoisomers of Diprionol and their Acetates, Components of the Sex Pheromone Pine Sawflies 1990 Ingår i: Tetrahedron. - 0040-4020. ; 46:8, s. 3007-3018 Tidskriftsartikel (refereegranskat)
30.	Janosik, T, et al. (författare) Reactions of 2,3 '-biindolyl: Synthesis of indolo[3,2-a]carbazoles 1999 Ingår i: TETRAHEDRON. - 0040-4020. ; 55:8, s. 2371-2380 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
31.	Janosik, Tomasz, et al. (författare) Synthesis of the marine alkaloids rhopaladins A, B, C and D 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:14, s. 2813-2819 Tidskriftsartikel (refereegranskat)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.
32.	Kuhn, Christian, et al. (författare) Fmoc protected peptide mimetic based on a cyclohexane framework and incorporation into angiotensin II 1997 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 53:37, s. 12497-12504 Tidskriftsartikel (refereegranskat)abstract 1,3,5-syn substituted cyclohexane based amino acids have been prepared and incorporated into synthetic peptides to serve as scaffold mimicking the Val-Tyr-Ile sequence of angiotensin II. The conformationally constrained tripeptide mimetic holds potential use as a γ-turn replacement.
33.	Laglet, Abraham, et al. (författare) Synthesis and Reactions of 1,1-dinitro-2,2-dinitroethylene 1998 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 54:38, s. 11525-11536 Tidskriftsartikel (refereegranskat)abstract Low temperature nitrations of 2-methylimidazole gave in addition to the known 2-methyl-5(4)-nitroimidazole (1), 2-(dinitromethylene)-5,5-dinitro-4-imidazolidinone (3) and parabanic acid (2). The tetranitro compound 3 was also obtained by nitration of 2-methyl-4,5-dihydro-(1H)-5-imidazolone (8). Thermal decomposition of 3 gave 2-(dinitromethylene)-4,5-imidazolidinedione (4) which also was the product from nitration of the new compound 2-methoxy-2-methyl-4,5-imidazolidinedione. Treatment of 4 with aqueous ammonia gave the previously unknown 1,1-diamino-2,2-dinitroethylene (5). The physical properties and chemical behaviour of (5) are described.
34.	LARHED, M, et al. (författare) CHELATION-CONTROLLED, PALLADIUM-CATALYZED ARYLATION OF ENOL ETHERS WITH ARYL TRIFLATES - LIGAND CONTROL OF SELECTION FOR ALPHA-ARYLATION OR BETA-ARYLATION OF [2-(DIMETHYLAMINO)ETHOXY]ETHENE 1994 Ingår i: Tetrahedron. - UPPSALA UNIV, UPPSALA BIOMED CTR, DEPT ORGAN PHARMACEUT CHEM, S-75123 UPPSALA, SWEDEN. ASTRA DRACO AB, PRECLIN RES & DEV, DEPT MED CHEM, S-22100 LUND, SWEDEN.. - 0040-4020 .- 1464-5416. ; 50:2, s. 285-304 Tidskriftsartikel (refereegranskat)abstract Palladium-catalyzed arylation reactions of [2-(Dimethylamino)ethoxy]ethene (1) with a series of aryl triflates were performed under a variety of reaction conditions. In particular, the influence of phosphine ligands and halide additives on regioselectivity were studied. It was found that the chelation-controlled arylation of 1 affords an expedient route for the conversion of phenols into arylacetaldehydes. Alternatively, the same starting materials could be used to synthesize acetophenones by reversing the regioselectivity with bidentate phosphine ligands.
35.	Larsson, Michael, et al. (författare) Diastereoselective addition of methylmetal reagents to 2-methylaldehydes. 2001 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 57:35, s. 7541-7548 Tidskriftsartikel (refereegranskat)abstract The preparation of compounds incorporating the 3-hydroxy-2-methyl-1-butyl moiety of high diastereomeric purity is described. These compounds can serve as potential building blocks for the preparation of several kinds of natural products. The diastereoselective addition of a number of methylmetal derivatives to three 3-substituted 2-methylaldehydes in various solvents was studied. An excellent diastereomeric. ratio (95:5 anti-Cram/Crain) was obtained with 2-methyl-3-(phenylsulfanyl)propanal (5) and Me2Zn in the presence of TiCl4.
36.	Latypov, NV, et al. (författare) Synthesis and reactions of 1,1-diamino-2,2-dinitroethylene 1998 Ingår i: TETRAHEDRON. - 0040-4020. ; 54:38, s. 11525-11536 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
37.	Lindberg, Jan, et al. (författare) Efficient routes to glucosamine-myo-inositol derivatives, key building blocks in the synthesis of glycosylphosphatidylinositol anchor substances 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:7, s. 1387-1398 Tidskriftsartikel (refereegranskat)abstract Short synthetic routes to protected derivatives of 2-amino-2-deoxy-a-D-glucopyranosyl-(1?6)-D-myo-inositol are described. Various 2-azido-2-deoxy-glucosyl donors were synthesized, starting from D-glucal or glucosamine hydrochloride. Derivatives of 1,2- and 2,3- D-myo-inositol-camphanylidene acetals were prepared to function as glycosyl acceptors. The subsequent glycosylations produced useful building blocks for the synthesis of GPI-anchor substances. © 2002 Elsevier Science Ltd. All rights reserved.
38.	Lindberg, Jan, et al. (författare) Synthesis of galactoglycerolipids found in the HT29 human colon carcinoma cell line 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:25, s. 5109-5117 Tidskriftsartikel (refereegranskat)abstract Synthesis of three galactoglycerolipids (3-O-(ß-D-galactopyranosyl)-1-O-hexadecyl-2-O-palmitoyl-sn-glycerol, 3-O-(a-D-galactopyranosyl-(1?4)-ß-D-galactopyranosyl)-1-O- hexadecyl-2-O-palmitoyl-sn-glycerol, 3-O-(a-D-galactopyranosyl-(1?4)-ß-D-galactopyranosyl)-1-O- hexadecyl-sn-glycerol), and the corresponding glycerolipid (1-O-hexadecyl-2-O-palmitoyl-sn-glycerol) is described. The first two compounds were recently identified in the human colon carcinoma cell line HT29. The three-carbon synthon (S)-glycidol was used for construction of the glycerol moiety. Glycosylation of (S)-glycidol with protected galactosyl and digalactosyl donors produced galactosyl and digalactosyl glycidols. Lewis acid catalyzed opening of the epoxide produced protected galactosyl and digalactosyl glycerolipids. Deprotection, or palmitoylation followed by deprotection, yielded the target compounds. The corresponding glycerolipid was synthesized analogously and an oxidation-reduction procedure for tritiation was developed. The synthesized compounds will be used in studies of the role of galactosyl glycerolipids in differentiation and colon cancer development. © 2002 Elsevier Science Ltd. All rights reserved.
39.	Lindberg, Jan, et al. (författare) Synthesis of inositol phosphoglycans containing thiol-terminated spacers for efficient coupling to maleimide functionalized solid phases or proteins 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:21, s. 4245-4254 Tidskriftsartikel (refereegranskat)abstract The synthesis of inositol phosphoglycans (IPGs), analogous to second messengers of insulin, to provide a small targeted library of compounds is described. These derivatives contain the glucosamine(a1-6)myo-inositol 1,2-cyclic phosphate motif. A thiol-terminated spacer was introduced, for their immobilization, by a radical elongation of an allyl ether with benzyl mercaptane. ⌐ 2002 Elsevier Science Ltd. All rights reserved.
40.	Marton, J., et al. (författare) Reaction of morphinan-6,8-dienes with azadienophiles 1996 Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 52:7, s. 2449-2464 Tidskriftsartikel (refereegranskat)abstract Reaction of various morphinan dienes, i.e. thebaine (1a), N-demethyl-N-formylthebaine (1b), 6-demethoxythebaine (1c), β-dihydrothebaine (2a), 4-acetoxy-β-dihydrothebaine (2b), 7-chloro-6-demethoxythebaine (3a) and 7-bromo-6-demethyoxythebaine (3b) with 4-phenyl-4H-1,2,4-triazoline-3,5-dione (PTAD) gave rise to new Diels-Alder (DA) adducts. DA-reaction of 1a, 1b and 1c with PTAD led to the products of the β-face attack of the dienophile at the diene unit. The W coupling (4J(5β,18)) in the 1H-NMR spectra was indicative of these structures. α-Face addition took place in the case of morphinan dienes with opened ring E, and a by-product was formed due to the S(E) reaction of PTAD with the adducts. The structure of these derivatives was confirmed by means of NMR spectroscopic methods. The retro Diels-Alder (rDA) reaction of the adducts 4a and 4b readily took place in polar-aprotic solvents in the presence of bases with low nucleophilic character.
41.	Marton, J., et al. (författare) Studies on the synthesis of β-thevinone derivatives 1998 Ingår i: Tetrahedron. - : Elsevier BV. - 0040-4020 .- 1464-5416. ; 54:31, s. 9143-9152 Tidskriftsartikel (refereegranskat)abstract The reactions of β-thevinone and β-dihydrothevinone with tert- butylmagnesium chloride and n-propylmagnesium bromide were investigated. Further chemical transformations (N-demethylation, N-alkylation, O- demethylation) of the tertiary alcohols afforded the known β-buprenorphine and the hitherto unknown β-etorphine and β-dihydroetorphine. The by- products of these reactions were also isolated, their structures identified, and the mode of their formation was explained.
42.	Nöteberg, Daniel, et al. (författare) Synthesis of enantiomerically pure cis and trans 2-aminocyclopentanecarboxylic acids. Use of proline replacements in potential HIV-protease inhibitors 1997 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 53:23, s. 7975-7984 Tidskriftsartikel (refereegranskat)abstract The synthesis of the four diastereomeric 2-aminocyclopentanecarboxylic acids, their use as replacements for proline in potential HIV protease inhibitors containing a hydroxyethylamine dipeptide isostere and the evaluation of the biological activity of these is described.
43.	Olofsson, Berit, et al. (författare) Synthesis of N-H vinylaziridines : a comparative study 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:30, s. 5979-5982 Tidskriftsartikel (refereegranskat)abstract Vinylaziridines are useful and versatile synthetic intermediates, as the relief of ring-strain provides a driving force for efficient ring-opening or ring-expansion reactions. Furthermore, the vinyl group can be derivatized into interesting functionalities. The ring-closure of vicinal amino alcohols constitutes a straightforward route to aziridines. Several methods exist for this transformation, although many cannot be applied to vinylaziridines due to their acid lability. This comparative study describes the most effective sequences for the formation of N-H vinylaziridines.
44.	Ray, C. A., et al. (författare) Diastereoselective Lewis acid-catalysed 4+2 cycloadditions of 3-alkyl-, 3-aryl- and 3-carboxyl-2H-azirines : a route to aziridine containing azabicyclo 4.1.0 heptanes and azatricyclo 2.2.1.0 nonanes 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:30, s. 5983-5987 Tidskriftsartikel (refereegranskat)abstract 3-Substituted-2H-azirines have been employed as 2pi components in Lewis acid-catalysed hetero Diels-Alder reactions with a variety of diene systems. A series of Lewis acids were screened for catalytic behaviour in the reaction between Danishefsky's diene and 3-phenyl-2H-azirine to give the cycloaddition adduct, and in most cases elevated temperature were required to effect cycloaddition. A noteworthy exception was a BF3.Et2O-catalysed cycloaddition which proceeded in less than I h between -70degreesC and -60degreesC. The cycloadditions were found to proceed with endo selectivity providing a single diastereoisomeric product. Benzyl 2H-azirine-3-carboxylates were found to be activated by Lewis acids and participate in endo selective cycloadditions at -20degreesC.
45.	Rewcastle, G W, et al. (författare) Reactions of 2-lithiated indoles with elemental sulfur. Formation of pentathiepino[6,7-b]indoles and indoline-2-thiones 2001 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 57:33, s. 7185-7189 Tidskriftsartikel (refereegranskat)abstract 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.
46.	Roue, N, et al. (författare) Synthesis of the marine alkaloid leucettamine B 1999 Ingår i: TETRAHEDRON. - 0040-4020. ; 55:51, s. 14729-14738 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
47.	Ruda, K., et al. (författare) Synthesis of an inositol phosphoglycan fragment found in Leishmania parasites 2000 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 56:24, s. 3969-3975 Tidskriftsartikel (refereegranskat)abstract Synthesis of 1 and 2a is described using a block synthetic strategy. Compound 4 was used as precursor for the two mannose derivatives which, coupled together, forms the dimannoside building block. Thioglycoside 7 was coupled to 8 yielding inositol phosphoglycan 9a, which was selectively deprotected and reacted with 2,3,4,6-tetra-O-benzyl-a-D-glucopyranos-1-yl H- phosphonate to form the protected target molecule 12. Deprotection of 12 by acidic deacetalisation/desilylation and subsequent catalytic hydrogenolysis resulted in cleavage of the anomeric phosphodiester to produce 1. Debenzylation with sodium in liquid ammonia followed by acidic deacetalisation/desilylation gave the target compound 2a. (C) 2000 Published by Elsevier Science Ltd.
48.	Slätt, Johnny, 1976-, et al. (författare) Oxygenation of 2,3-dihydroindoles. 2002 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 58:45, s. 9187-9191 Tidskriftsartikel (refereegranskat)abstract Indolines (2,3-dihydroindoles) and isatogens (3-oxo-3H-indole 1-oxides) have been prepd. in an efficient route starting from indoles substituted in position 2. Redn. 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). [on SciFinder(R)]
49.	Smitt, Olof, et al. (författare) Syntheses of a prenylbisabolane diterpene, a natural insecticide from Croton linearis, and of the bisabolane sesquiterpenes (-)-delobanone and (-)-epi-delobanone 2002 Ingår i: Tetrahedron. - 0040-4020. ; 58:38, s. 7691-7700 Tidskriftsartikel (refereegranskat)abstract An enantioselective first total synthesis of a constituent of Croton linearis, the (-)-7-hydroxy-3,10-prenylbisaboladien-2-one 1, is described as well as the syntheses of the 7-hydroxy-3,10-bisaboladien-2-ones (-)-epi-delobanone (14a) and (-)-delobanone (14b). The model compounds, 7-hydroxy-11-nor-methyl-3-bisabolen-2-one (8a), and 11,15-nor-dimethyl-7-hydroxy-3-bisabolen-2-one (8b), were successfully prepared by opening of the protected carvone epoxide derivative 6 with the appropriate organocuprates. An alternative approach was used for compounds 1 and 14. Thus, these were obtained from homogeranyllithium or homoprenyl Grignard reagent, which reacted successfully with a masked nor-carvone, ketone 11, prepared in four steps from (R)-carvone.
50.	Somfai, Peter, et al. (författare) Asymmetric synthesis of (+)-1-deoxynojirimycin and (+)-castanospermine 2003 Ingår i: Tetrahedron. - 0040-4020 .- 1464-5416. ; 59:8, s. 1293-1299 Tidskriftsartikel (refereegranskat)abstract Asymmetric total syntheses of (+)-1-deoxynojirimycin (1) and (+)-castanospermine (2) are described. Starting from diene 3, the required absolute stereochemistry is introduced by an asymmetric hydroxylation followed by epoxidation. An intramolecular cyclization of amine 17 gives access to the corresponding tetrasubstituted piperidine 18, which is a precursor to compounds 1 and 2. (+)-Deoxynojirimicyn (1) was obtained in 36% yield over 11 steps from diene 3, while (+)-castanospermine (2) was achieved in 13% after 19 steps from the same starting material.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "L773:0040 4020 "

Avgränsa träffmängd

År