- Influence Of Lithium Coordinating Additives On The Structure Of Phenyldimethylsilyllithium
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The synthesis and structural investigation of two dimethylphenylsilyllithium adducts with coordinating nitrogen donors quinuclidine and 1,3,5-tri-tert-butylhexahydro-1,3,5-triazine (tbtac) are presented. The structures show a comparatively long Si?Li distance and one amongst the shortest in monomeric silyllithiums reported so far, respectively. The structural investigations shed light on the influence of the donating additive for the lithium center on the structure of silyllithium compounds.
- Achternbosch, Moritz,Brieger, Lukas,Strohmann, Carsten
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- Synthesis, crystal structure, and spectral characteristics of N-(tert-Butyl)aminomethanesulfonic acid
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A new method of the synthesis of N-(tert-butyl)aminomethanesulfonic acid in the system SO2-(CH3)3CNH2-CH2O-H2O was developed. The target compound [(CH3)3C]NHCH2SO3H was characterized by means of X-ray diffraction analysis, IR spectroscopy, and mass spectrometry.
- Khoma,Gel'mbol'dt,Ennan,Baumer,Puzan
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- Reaction of Rifamycins with Hexahydro-1,3,5-triazines Prepared from Formaldehyde and Primary Aliphatic Amines
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Rifamicin S (1) and 25-O-deacetylrifamycin S reacted with 1,3,5-tributylhexahydro-1,3,5-triazine to give deep-blue compounds.The structures of the deep-blue compounds are discussed based on 13C NMR data, and it is concluded that the earlier structures should be partly re-revised.The mechanism of formation of the deep-blue compounds and the reaction of 1 with several hexahydro-1,3,5-triazines, which were prepared from formaldehyde and primary aliphatic amines, are also described.
- Taguchi, Masahiro,Aikawa, Norio,Tsukamoto, Goro
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- Oligomerization catalyst
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An oligomerization catalyst for olefins is obtainable from a) a chromium compound CrX3 and the at least equimolar amount, based on the chromium compound CrX3, of a ligand L or from an existing chromium complex CrX3L, in which the groups X are, independently of one another, abstractable counterions and L is a 1,3,5-triazacyclohexane of the formula I ?where the groups R1 to R9 are, independently of one another: hydrogen or organosilicon or substituted or unsubstituted carboorganic groups having from 1 to 30 carbon atoms, where two geminal or vicinal radicals R1 to R9 may also be joined to form a five—or six-membered ring, andb) at least one activating additive and also a process for preparing oligomers of olefins using these catalysts, the oligomers thus obtainable, and the oxo alcohols obtainable from these oligomers.
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- OLIGOMERISATION CATALYST
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An oligomerization catalyst for olefins is obtainable froma) a chromium compound CrX3 and the at least equimolar amount, based on the chromium compound CrX3, of a ligand L or from an existing chromium complex CrX3L, in which the groups X are, independently of one another, abstractable counterions and L is a 1,3,5-triazacyclohexane of the formula Iwhere the groups Rto Rare, independently of one another: hydrogen or organosilicon or substituted or unsubstituted carboorganic groups having from 1 to 30 carbon atoms, where two geminal or vicinal radicals Rto Rmay also be joined to form a five-or six-membered ring, andb) at least one activating additiveand also a process for preparing oligomers of olefins using these catalysts, the oligomers thus obtainable, and the oxo alcohols obtainable from these oligomers.
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Page/Page column 9
(2008/06/13)
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- N-BH3 ADDUCTS OF TRIALKYL-1,3,5-TRIAZACYCLOHEXANES WITH STABLE STEREOGENIC NITROGEN ATOMS, STEREOCHEMICAL STUDY
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The syntheses and stereochemical studies of N-BH3 adducts of trialkyl-1,3,5-triazacyclohexanes are reported.Different reagent ratios were used in order to obtain mono- and di-N-borane adducts.Tri-N-borane adducts were never observed; di-N-borane adducts were formed with triazine 1 and 2 whereas 3 and 4 afforded only the mono-boranes.It appears that low steric strain is an important factor in the syntesis of these compounds.Borane addition produced in all cases ring and nitrogen conformationally stable compounds which were studied by NMR All the reactions were 100percent stereoselective affording one isomer in each reaction.
- Martinez-Aguilera, Luz M. Ruth,Cadenas-Pliego, Gregorio,Contreras, Rosalinda,Flores-Parra, Angelina
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p. 1585 - 1592
(2007/10/02)
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- Synthesis of dicationic diarylpyridines as nucleic-acid binding agents
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The syntheses of 2,6-bis[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]pyridine 7, 2-[4-(4,5-dihydro-1H-imidazol-2-yl)-phenyl]-6-[3-(4,5-dihydro- 1H-imidazol-2-yl)phenyl]pyridine 8 and 2,6-bis[3-(4,5-dihydro-1H-imidazol-2-yl)phenyl]pyridine 9 in five steps from the appropriately substituted bromoacetophenone are described. 3,5-Bis[4-(4,5-dihydro-1H-imidazol-2-yl) phenyl]pyridine 13 is also reported, prepared in four steps from 4-bromophenylacetonitrile. The preparation of 2,5-bis[4-(4,5-dihydro-IH-imidazol-2-yl) phenyl]pyridine Is from 4-bromoacetophenone in six steps is presented. The dications bind to poly dA·dT in the order 7 > 13 > 18 > 8 > 9; the order of binding to poly A·U is 7 > 13 > 8 > 9; 18 essentially does not bind to the RNA model. Only 7 inhibits topoisomerase II at millimolar concentrations. The dicationic compounds that were tested against Pneumonocystis carinii in the immunosuppressed rat model show only modest activity and are moderately toxic. Some of the compounds demonstrated modest anti-HIV-1 activity and selectivity in primary lymphocytes.
- Kumar,Rhodes,Spychala,Wilson,Boykin,Tidwell,Dykstra,Hall,Jones,Schinazi
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- Preparation of N,O-Aminals as Synthetic Equivalents of H2C=NAr and (H2C=NHAr)+ ions: Neutral- and Acid-promoted Transformations
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A general method for the synthesis of N, O-aminals derived from primary aromatic amines is described.The reactivity of these compounds under neutral and acidic conditions has been studied and the title compounds can be envisaged as general purpose H2C=NAr or (H2C=NAr)+ equivalents.N,O-Aminals have been converted into perhydrotriazines by moderate heating and into bis(4-aminoaryl)methane derivatives or N-benzylarylamines, respectively, when heated in acidid media with pH control.Reduction od N,O-acetals with sodium cyanoborohydride has revealed that the C-O bond is broken exclusively in acidic media.
- Barluenga, Jose,Bayon, Ana M.,Campos, Pedro,Asensio, Gregorio,Gonzalez-Nunez, Elena,Molina, Yolanda
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p. 1631 - 1636
(2007/10/02)
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