- CYCLOADDITION REACTIONS OF 1,3-DIACETYLIMIDAZOLIN-2-ONE
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1,3-Diacetylimidazolin-2-one, for wich a new preparation is described, has been found to undergo thermal cycloaddition reactions with a limited number of dienes; in contrast it undergoes photochemical cycloadditions quite readily.
- Whitney, Ralph A.
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- Stabilization of radicals by imides. A modular stereoselective approach to protected functional 1,2-diamines
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(Chemical Equation Presented) Radical addition of various xanthates to N,N′-diacylimidazol-2-one occurs readily to give protected 1,2-diamines. The imide group stabilizes the adduct radical sufficiently to enable a second addition to unactivated alkenes. In some cases, the addition product could be converted into an indoline, a tetralone, or further added to an indole. Regioselective removal of one acyl group could also be accomplished.
- Han, Songzhe,Zard, Samir Z.
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- Synthesis of norbornahemicucurbiturils
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Ethyleneurea fused with a norbornane ring was prepared. Acid-catalyzed polycondensation of the urea with paraformaldehyde yielded a new six-membered hemicucurbituril derivative. The presence of hemicucurbiturils containing from four to eight monomer units were also detected. Georg Thieme Verlag Stuttgart, New York.
- Fiala, Tomas,Sindelar, Vladimir
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- Lewis Acid Catalyzed Enantioselective Desymmetrization of Donor–Acceptor meso-Diaminocyclopropanes
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The first Lewis acid catalyzed enantioselective ring-opening desymmetrization of a donor–acceptor meso-diaminocyclopropane is reported. The copper(II)-catalyzed Friedel–Crafts alkylation of indoles and one pyrrole with an unprecedented meso-diaminocyclopropane delivered enantioenriched, diastereomerically pure urea products, which are structurally related to natural and synthetic bioactive compounds. The development of a new ligand through the investigation of an underexplored subclass of bis(oxazoline) ligands was essential for achieving high enantioselectivities.
- Perrotta, Daniele,Wang, Ming-Ming,Waser, Jér?me
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supporting information
p. 5120 - 5123
(2018/03/27)
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- Schwartz reagent mediated synthesis of thiazolones and imidazolones from thiazolidine-2,4-diones and imidazolidine-2,4-diones
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A novel reduction/elimination method of thiazolidine-2,4-dione and imidazolidine-2,4-dione derivatives using Schwartz reagent to synthesize numerous thiazolones and imidazolones in a single step is reported.
- Dandepally, Srinivasa Reddy,Elgoummadi, Radouane,Williams, Alfred L.
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p. 925 - 928
(2013/02/25)
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- Synthesis of N-heterocyclic compounds via ene-yne metathesis reactions
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Propargylamino and allylamino derivatives of cyclohexene and norbornene were subjected to tandem metathesis reactions with first and second generation Grubbs' catalysts 1 and 2. Results show that the method is compatible with suitably protected nitrogen-containing compounds. Cyclohexenes gave intriguing results in terms of the possibility to perform ring rearrangement metathesis (RRM) reactions, showing a difference with the analogous allyl and propargyl ether substrates.
- Groaz, Elisabetta,Banti, Donatella,North, Michael
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p. 204 - 218
(2008/03/28)
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- Substituted heterocycles
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Compounds of formula I STR1 wherein Q1, Q2, Q3, Q4 and Q5 have any of the meanings given in the specification, their N-oxides, and their pharmacuetically acceptable salts are nonpeptide antagonists NKA, useful for the treatment of asthma, etc. Also disclosed are pharmaceutical compositions, processes for preparing the compounds of formula I and intermediates.
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- Synthesis and characterization of 1,2,3,4-cyclobutanetetranitramine derivatives
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A series of new nitramines have been synthesized. All of the new compounds possess four nitramine moieties arranged about a cyclobutane ring in a 1α,2α,3β,4β (cis,trans,cis) configuration. One of the new materials, 1, is unusually thermally and hydrolytically stable but sensitive to impact. 1,2,3,4-Cyclobutanetetranitramine (3) is reported for the first time.
- Fischer, John W.,Hollins, Richard A.,Lowe-Ma, Charlotte K.,Nissan, Robin A.,Chapman, Robert D.
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p. 9340 - 9343
(2007/10/03)
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- Synthesis and Biological Activity of 9-Mercaptodethiobiotin - a Putative Biotin Precursor in Escherichia coli
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A total synthesis of (+/-)-9-mercaptodethiobiotin 3 via the aldehyde 9 is described.Compound (+/-)-3 does not function as a biotin replacement factor for an E. coli mutant (SA291) lacking the entire biotin synthesis operon (bioABFCD-) but supports growth of an E. coli bioA mutant.Compound (+/-)-3 also supports growth of transformed cells of SA291 carrying a plasmid encoding the E. coli biotin synthase (bioB) gene indicating that the compound may be able to substitute for dethiobiotin 2 as a substrate for biotin synthase.
- Baxter, Robert L.,Camp, Dominic J.,Coutts, Andrew,Shaw, Nicholas
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p. 255 - 258
(2007/10/02)
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- 1-Hydroxyimidazole Derivatives; I. Synthesis of 1-Hydroxy- and 1-Alkoxy-2,3-dihydroimidazole-2-ones
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Two alternative methods (A,B) are applied to prepare new 1-hydroxy- and 1-alkoxy-2,3-dihydroimidazole-2-ones.One of the favorable educts, 2,2-diethoxyethyl isocyanate, is obtained by a convenient method.
- Bock, Veronika,Kloetzer, Wilhelm,Singewald, Nicolas,Strieder, Georg
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p. 1058 - 1060
(2007/10/02)
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- Syntheses and Structure Assignments of Six Azolinone Ribonucleosides
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N-Ribosidation of a series of azolinones was achieved via silylation and SnCl4 catalysis.N-Ribosidation of 4-imidazolin-2-one gave 1-β-D-ribofuranosyl-4-imidazolin-2-one; of 1,2,4-triazolin-3-one gave 2- and 4-β-D-ribofuranosyl-1,2,4-triazolin-3-one, and 2,4-di-β-D-ribofuranosyl-1,2,4-triazolin-3-one; and of 2-tetrazolin-5-one gave 1-β-D-ribofuranosyl-2-tetrazolin-5-one and 1,4-di-β-D-ribofuranosyl-2-tetrazolin-5-one.Structure assignments were based on NMR and mass spectra, microanalytical data, and interconversions.The triazolinone monoriboside isomer structures were differentiated by 13C NMR long-range coupling patterns, and the assignments were confirmed by X-ray crystallography.New syntheses were developed for several of the ribonucleosides by fashioning the azolinone rings from 2,3,5-tri-O-benzoylribofuranosyl isocyanate.
- Haines, David R.,Leonard, Nelson J.,Wiemer, David F.
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p. 474 - 482
(2007/10/02)
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- RING OPENING AND CLOSING REACTIONS OF IMIDAZOLES AND OTHER 1,3-DIAZAHETEROCYCLES WITH VINYL CHLOROFORMATE AND PHENYL CHLOROFORMATE
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Treatment of imidazole and benzimidazole with vinyl chloroformate or phenyl chloroformate in weakly alkaline aqueous solution leads to their conversion into the corresponding imidazol-2-ones; in weakly acidic solutions these chloroformates convert adenine into isoquanine, 6-methylaminopurine into 1-methylisoquanine and pyrimidine into an acyclic product.
- Pratt, R. F.,Kraus, K. K.
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p. 2431 - 2434
(2007/10/02)
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