- Hydrogen bonded calixarene capsules kinetically stable in DMSO
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Half-life times up to 4 days in DMSO at room temperature are observed for the decomposition of dimeric capsules of urea substituted calix[4]arenes held together by a combination of hydrogen bonds, mechanical entanglement and cation-π interactions.
- Vysotsky,Thondorf,Boehmer
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- Synthesis and properties of tetraalkylammonium chlorides peroxosolvates (CH3)4NCI·H2O2 and (C 2H5)4NCl·H2O2
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Tetraalkylammonium chlorides peroxosolvates (CH3) 4NCl·H2O2 and (C2H 5)4NCl·H2O2 were synthesized. The composition of the solvates was proved by chemical analysis; their X-ray patterns, IR spectra, and thermograms were obtained. The solubility of the solvates in water and their stability in aqueous solutions were investigated.
- Titova,Nikol'skaya,Buyanov,Pudova,Karzhavina,Zharkova
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- Pyrolysis Reaction of Carpronium Chloride and its Structurally Realated Compounds. 2-A Mass Spectrometric Study of The Lactonization Mechanism
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The mechanism of the pyrolysis reaction of carpronium chloride +-(CH2)3-COOCH3Cl-> leading to γ-butyrolactone and tetramethylammonium chloride was investigated by means of thermal analysis, pyrolysis gas chromatography mass spectrometry and field desorption mass spectrometry, using deuterium labelling.The results indicated that carpronium chloride pyrolysed to yield equimolar amounts of γ-butyrolactone and tetramethylammonium chloride, methyl transfer occured between N and O during the pyrolysis process.The mechanism is discussed on the basis of the experimental results, and with the aid of the theoretical results calculated by the CNDO/2 method.The mechanism presented is as follows. γ-Butyrolactone is formed by the intramolecular migration of the ?-orbital of C=O to the carbon adjacent to + via a 5-membered ring transition state, accompained by a bimolecular reaction between + and the CH3 of O-CH3, resulting in the formation of tetramethylammonium chloride in an amount equimolar with γ-butyrolactone.
- Ohya, Kazumi,Kitaoka, Hiroaki,Yotsui, Yasuhiko,Sano, Mitsuji
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- Alkylation of ammonium salts catalyzed by imidazolium-based ionic liquid catalysts
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Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over imidazolium ionic liquid catalysts. The reaction gave almost stoichiometric amounts of the quaternary ammonium salts for halides and nitrates. It was found that the electron-donating property of the alkyl moieties of ammonium cations, the electrophilic nature of the alkyl group of the carbonate, the acidity of the acid that the anion of the ammonium salt corresponds to, and the steric hindrance of the ammonium salts and the dialkyl carbonates are the key factors that influence the yields of quaternary ammonium salts. Strong electron-donating alkyl groups on the nitrogen atom of the ammonium salt, electron-withdrawing groups on the methylene carbon of dialkyl carbonate, and weaker steric hindrance of the starting ammonium salts and dialkyl carbonates favor the alkylation reaction of ammonium salts.
- Zheng, Zhuo Qun,Wang, Jie,Wu, Ting Hua,Zhou, Xiao Ping
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p. 1095 - 1101
(2008/03/27)
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- Method of hybridizing genes
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Provided are a method of hybridizing genes, including applying to a gene microarray a hybridization solution in which a compound represented by formula (1) is added: where each of R1, R2, and R3 is independently a straight or branched C1-C5 alkyl; and X?is an anion of an organic acid; and a method of using a compound represented by formula (1) as an additive to a hybridization solution.
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- The synthesis of quaternary ammonium salts from ammonium salts and dialkyl carbonate
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Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over an ionic liquid catalyst 1-ethyl-3-methylimidazolium bromide. The Royal Society of Chemistry 2006.
- Zheng, Zhuoqun,Wu, Tinghua,Zhou, Xiaoping
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p. 1864 - 1865
(2008/03/14)
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- Quinolinium dyes and borates in photopolymerizable compositions
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Dye compounds of the formula wherein X is for example CH, C-CH3 or +NOR L-; R is inter alia C1-C6alkyl; R1 is for example C1-C8alkoxy or C1-C12alkyl; s is 0 to 4; R2 is for example hydrogen; Ar is for example a group Y inter alia is C1-C6alkyl or C1-C6alkoxy; r in the formula (A) is 0 to 5, in the formulae (B) and (E) is 0 to 9 and in the formula (D) is 0 to 7; and L is an anion; in combination with an electron donor compound, especially a borate compound, are suitable as photoinitiators for the photopolymerization of radically polymerizable compositions.
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- Lipopolyamines as transfection agents and pharamaceutical uses thereof
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PCT No. PCT/FR95/01595 Sec. 371 Date Jun. 4, 1997 Sec. 102(e) Date Jun. 4, 1997 PCT Filed Dec. 4, 1995 PCT Pub. No. WO96/17823 PCT Pub. Date Jun. 13, 1996Cationic lipids of general formula (I), wherein m is an integer from 2 to 6 inclusive; n is an integer from 1 to 9 inclusive, preferably 1-5, where, when n is 2-9, a single R grouping other than hydrogen is present in the general formula, and m has variable or identical values within the groupings (a) or -(CH2)m; R is a hydrogen atom or a radical of general formula (II), wherein X or X1, which are the same or different, are an oxygen atom, a methylene grouping -(CH2)q- where q is 0, 1, 2 or 3, or an amino grouping -NH- or NR1-, where R is a C1-4 alkyl grouping; Y and Y1, which are the same or different, are a hydrogen atom or an optionally substituted C1-4 alkyl radical, and p is 0-5; and R6 is a cholesterol derivative or an alkylamino grouping -NR1R2, where R1 and R2 are, independently of each other, a straight or branched, saturated or unsaturated C12-22 aliphatic radical. Pharmaceutical compositions containing said lipids, and their uses for transfecting nucleic acids whether in vitro or in vivo in cells, are also disclosed.
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- Competition between Triborane as a Ligand and a Hybride Donor at Platinum Centres containing Chelating Phosphines: Molecular Structures of PtB3H7>, PtB3H7> and 2>Cl
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The reaction of 5-C5H4PPh2)2> with the octahydrotriborate(1-) anion, -, leads to both in which the borane unit acts as a pseudo-bidentate ligand and Cl which results from the borane anion functioning as a hydride donor.For each of the complexes containing a bis(diphenylphosphino)alkane ligand the major product is PtB3H7>, whereas for the reaction of - with 5-C5H4PPh2)2>, 2>Cl is the predominant species formed.Three productshave been structurally characterised: PtB3H7> 1, space group P21/c, a = 16.049(4), b = 15.395(4), c = 21.075(5) Angstroem, β = 90.53(2) deg, Z = 8, R = 0.039; PtB3H7> 3, space group P21, a = 8.8826(18), b = 17.7329(32), c = 9.5520(17) Angstroem, β = 114.115(15) deg, Z = 2, R = 0.032; 2>Cl*3CH2Cl2 6, space group P21/c, a = 12.862(2), b = 38.732(6), c = 14.271(2) Angstroem, β = 99.027(15) deg, Z = 4, R = 0.067.The structure of the cation of 6 resembles that of 2>+ rather than that of t2P(CH2)3PBut2>2>+ thereby indicating that it is the steric bulk of the phosphorus substituents rather than the P-Pt-P bite angle that controls the geometry of the framework and thus the hydride locations.Fenske-Hall molecular orbital calculations have been used to probe the mode of bonding of the hydride ligands to the diplatinum centre.
- Haggerty, Brian S.,Housecroft, Catherine E.,Rheingold, Arnold L.,Shaykh, Bilal A. M.
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p. 2175 - 2184
(2007/10/02)
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- SYNTHESIS OF ARYLTHALLIUM COMPLEXES USING ORGANOMERCURY COMPOUNDS. CRYSTAL AND MOLEULAR STRUCTURES OF AND
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The reaction of or with 2 (1:2) affords or respectively.These two anionic complexes react with NaClO4 to give the neutral compounds and .The crystal structure of shows a distorted trigonal bipyramidal geometry around the thallium atom, if the rather weak interaction between thallium and the farther N atom is included.The nitrogen and carbon atoms occupy axial and equatorial sites, respectively, and a five-memberd TlC2N2 ring is observed.The The Tl-Cl distances are normal, with Tl-Clax longer than Tl-Cleq . the crystal structure of consists of a dimer with two asymmetric chlorine bridges .The chelkating ligand again gives rise to a five-membered ring, here TlC3N.Each thallium atom has a distorted trigonal bipyramidal environment in which the axial positions are occupied by the nitrogen atom of the aryl ligand and the weakly bonded bridging chlorine.The equatorial sites are occupied by the carbon atom of the aryl ligand , the other bridging chlorine, and a terminal chlorine .
- Vicente, Jose,Abad, J. Antonio,Gutierrez-Jugo, Juan F.,Jones, Peter G.
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p. 2241 - 2246
(2007/10/02)
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- ASYMMETRIC NITROGEN - 70. GEMINAL SYSTEMS - 44. TRIALKOXYAMINES(ORTHONITRITES). SYNTHESIS AND PROPERTIES
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The chlorination of acyclic N,N-dialkoxyamines under the action of tert-BuOCl results in the formation of unstable N-chloro-N,N-dialkoxyamines wich in situ react with sodium methoxide to give previously unknown trialkoxyamines (orthonitrites).The properties of the N-chloro-N,N-dialkoxy- and trialkoxyamines have been demonstrated to be similar to those of their carbon analogues: dialkoxyalkylchlorides and orthoesters, respectively.
- Rudchenko, Vladimir F.,Ignatov, Sergei M.,Chervin, Ivan I.,Kostyanovsky, Remir G.
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p. 2233 - 2240
(2007/10/02)
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- Phosphoryl to carbonyl migration of amino groups in mixed anhydrides
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Mixed anhydrides derived from carboxylic and aminophosphoric acids, (RO)(R'2N)P(O)OC(O)R'' (1), undergo unimolecular fragmentation yielding carboxyamides, R''C(O)NR'2, and metaphosphate esters, ROPO2.The mechanism of the amino group transfer was studied for substrate 1a (1, R = R' = Me; R'' = Ph); solvent as well as substituent effects indicate little (if any) charge development in the transition state.The effects of solvents and Lewis acids on the reaction rate and the activation parameters determined for 1a can be explained best in terms of stabilizing interactions with either carboxyamide or metaphosphate being formed in the course of reaction.The transfer of a functional group from one acyl center to another was investigated for other anhydride systems and the relative contributions of the fragmentation vs. disproportionation of substrates are discussed.
- Symes, Jill,Modro, Tomasz A.
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p. 1702 - 1708
(2007/10/02)
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- QUASIPHOSPHONIUM INTERMEDIATES. PART V. THE FORMATION OF ALKOXYPHOSPHONIUM INTERMEDIATES AND OF PHOSPHORUS-NITROGEN FISSION PRODUCTS IN REACTIONS OF NEOPENTYL N,N,N',N'-TETRAMETHYLPHOSPHORODIAMIDITE WITH HALOGENOMETHANES
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Alkoxyphosphonium halides are obtained as intermediates in the reactions of neopentyl N,N,N',N'-tetramethylphosphorodiamidite with chloro-, bromo-, iodo-methane.Whereas the iodide and bromide are well-defined crystalline solids, the chloride is low-melting and deliquescent.All are stable at room temperature and are hydrolysed only slowly.Thermal decomposition in deuterochloroform at 100 deg C gives neopentyl halides and methanephosphonic bisdimethylamide by SN2-type cleavage of the alkyl-oxygen bond.The presence of moisture may give rise also to the formation of dimethylammonium salts.In reactions of the phosphorodiamidite with bromo- or chloro-methane, competing quaternization at nitrogen and the formation of trimethylamine (and hence of tetramethylammonium halides) may be correlated with increasing hardness of the halide in the order I Br Cl.
- Hudson, Harry R.,Powroznyk, Luba,Qureshi, A. Rauf
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p. 289 - 296
(2007/10/02)
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- Monocarbon carboranes. I. Syntheses and reactions of the B10H12CH- and B10H10CH- ions and their C-trialkylamine derivatives
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Deamination of B10H12CNR3 with either sodium hydride or sodium metal in refluxing tetrahydrofuran gave the B10H12CH- ion. In the latter reaction an air-sensitive intermediate was isolated which appears to be Na3B10H10CH(C4H8O) 1·8. Iodine oxidation of the trisodium salt produced the B10H10CH- ion in high yield. Halogenated derivatives of B10H12CNR3 and B10H12CH- have been prepared and the position of substitution determined by a 11B nmr study of a specifically labeled bromo derivative.
- Hyatt, David E.,Scholer, Frederick R.,Todd, Lee J.,Warner, Janet L.
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p. 2229 - 2233
(2008/10/08)
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