37688-96-3Relevant articles and documents
Electrostatic Control of Macrocyclization Reactions within Nanospaces
Wang, Kaiya,Cai, Xiaoyang,Yao, Wei,Tang, Du,Kataria, Rhea,Ashbaugh, Henry S.,Byers, Larry D,Gibb, Bruce C.
, p. 6740 - 6747 (2019/05/06)
The intrinsic structural complexity of proteins makes it hard to identify the contributions of each noncovalent interaction behind the remarkable rate accelerations of enzymes. Coulombic forces are evidently primary, but despite developments in artificial nanoreactor design, a picture of the extent to which these can contribute has not been forthcoming. Here we report on two supramolecular capsules that possess structurally identical inner-spaces that differ in the electrostatic potential (EP) field that envelops them: one positive and one negative. This architecture means that only changes in the EP field influence the chemical properties of encapsulated species. We quantify these influences via acidity and rates of cyclization measurements for encapsulated guests, and we confirm the primary role of Coulombic forces with a simple mathematical model approximating the capsules as Born spheres within a continuum dielectric. These results reveal the reaction rate accelerations possible under Coulombic control and highlight important design criteria for nanoreactors.
Non-metal-templated approaches to bis(borane) derivatives of macrocyclic dibridgehead diphosphines via alkene metathesis
Fiedler, Tobias,Barbasiewicz, Micha?,Stollenz, Michael,Gladysz, John A.
, p. 2354 - 2365 (2018/09/14)
Two routes to the title compounds are evaluated. First, a ca. 0.01 M CH2Cl2 solution of H3B·P((CH2)6CH=CH2)3 (1·BH3) is treated with 5 mol % of Grubbs' first generation catalyst (0 °C to reflux), followed by H2 (5 bar) and Wilkinson's catalyst (55 °C). Column chromatography affords H3B·P(n-C8H17)3 (1%), H3B·P((CH2)13CH2)(n-C8H17) (8%; see text for tie bars that indicate additional phosphorus–carbon linkages, which are coded in the abstract with italics), H3B·P((CH2)13CH2)((CH2)14)P((CH2)13CH2)·BH3 (6·2BH3, 10%), in,out-H3B·P((CH2)14)3P·BH3 (in,out-2·2BH3, 4%) and the stereoisomer (in,in/out,out)-2·2BH3 (2%). Four of these structures are verified by independent syntheses. Second, 1,14-tetradecanedioic acid is converted (reduction, bromination, Arbuzov reaction, LiAlH4) to H2P((CH2)14)PH2 (10; 76% overall yield). The reaction with H3B·SMe2 gives 10·2BH3, which is treated with n-BuLi (4.4 equiv) and Br(CH2)6CH=CH2 (4.0 equiv) to afford the tetraalkenyl precursor (H2C=CH(CH2)6)2(H3B)P((CH2)14)P(BH3)((CH2)6CH=CH2)2 (11·2BH3; 18%). Alternative approaches to 11·2BH3 (e.g., via 11) were unsuccessful. An analogous metathesis/hydrogenation/chromatography sequence with 11·2BH3 (0.0010 M in CH2Cl2) gives 6·2BH3 (5%), in,out-2·2BH3 (6%), and (in,in/out,out)-2·2BH3 (7%). Despite the doubled yield of 2·2BH3, the longer synthesis of 11·2BH3 vs 1·BH3 renders the two routes a toss-up; neither compares favorably with precious metal templated syntheses.
Improved Syntheses of Benzyl Hydraphile Synthetic Cation-Conducting Channels
Curvey, Nichole S.,Luderer, Sarah E.,Walker, John K.,Gokel, George W.
, p. 2771 - 2779 (2015/02/19)
The tris(macrocycle)s that function in bilayer membranes as ion channels have recently shown versatile new applications such as antibiotic synergists and as agents for direct injection chemotherapy. This report records the development of new and versatile approaches to these molecules that produce significantly better overall yields for a group of previously reported hydraphiles having spacer chains ranging from octylene to hexadecylene.
Structure dependence of long-chain [18F]fluorothia fatty acids as myocardial fatty acid oxidation probes
Pandey, Mukesh K.,Belanger, Anthony P.,Wang, Shuyan,Degrado, Timothy R.
, p. 10674 - 10684 (2013/02/23)
In vivo imaging of regional fatty acid oxidation (FAO) rates would have considerable potential for evaluation of mammalian diseases. We have synthesized and evaluated 18F-labeled thia fatty acid analogues as metabolically trapped FAO probes to understand the effect of chain length, degree of unsaturation, and placement of the thia substituent on myocardial uptake and retention. 18-[18F]Fluoro-4-thia-(9Z)-octadec-9-enoic acid (3) showed excellent heart/background radioactivity concentration ratios along with highest retention in heart and liver. Pretreatment of rats with the CPT-1 inhibitor, POCA, caused >80% reduction in myocardial uptake of 16-[ 18F]fluoro-4-thiahexadecanoic acid (2) and 3, indicating high specificity for FAO. In contrast, 18-[18F]fluoro-4-thiaoctadecanoic acid (4) showed dramatically reduced myocardial uptake and blunted response to POCA. 18-[18F]Fluoro-6-thiaoctadecanoic acid (5) showed moderate myocardial uptake and no sensitivity of myocardial uptake to POCA. The results demonstrate relationships between structures of 18F-labeled thia fatty acid and uptake and their utility as FAO probes in various tissues.
A photoirradiative phase-vanishing method: Efficient generation of HBr from alkanes and molecular bromine and its use for subsequent radical addition to terminal alkenes
Matsubara, Hiroshi,Tsukida, Masaaki,Ishihara, Daisuke,Kuniyoshi, Kenji,Ryu, Ilhyong
experimental part, p. 2014 - 2018 (2010/10/02)
A triphasic phase-vanishing (PV) system comprised of an alkane, perfluorohexanes, and bromine was successfully combined by photoirradiation to efficiently generate hydrogen bromide, which underwent radical addition with 1-alkenes in the hydrocarbon layer to afford terminal bromides in high yields. Georg Thieme Verlag Stuttgart.
First syntheses of model long-chain trichloro[ω-(trimethylsilyl)alkynyl]silanes suitable for self-assembled monolayers on silicon surfaces
Banaszak, Estelle,Xu, Li-Wen,Bardeau, Jean-Fran?ois,Castanet, Anne-Sophie,Mortier, Jacques
body text, p. 3961 - 3966 (2009/09/30)
The preparation of the title compounds involves the introduction of the required Me3SiC{triple bond, long}C and trichlorosilyl groups at the termini of the alkyl chain via derivatization of easily accessible and inexpensive materials/reagents. Trichloro[ω-(trimethylsilyl)alkynyl]silanes are useful for the linkage to a hydroxylated silicon surface for multilayer formation and for further chemical modification of the tail group of the monolayer.
Cuprate-Mediated 11C-C Coupling Reactions Using Grignard Reagents and 11C-Alkyl Iodides
Kihlberg, Tor,Laengstroem, Bengt
, p. 570 - 577 (2007/10/02)
Various 11C-labelled alkyl iodides were reacted with Grignard reagents in syntheses of labelled fatty acids, alkenes and aromatic compounds.Fatty acids were labelled in a number of positions by the combination of specifically labelled alkyl iodides and Grignard reagents of different chain lengths.The positions of the label were confirmed by 13C-labelling and NMR spectroscopy.Dilithium tetrachlorocuprate was used, except in the coupling reaction with short-chain bis-Grignard reagents, where 2-thienylcuprate was employed.In the cases when methyl iodide and dilithium tetrachlorocuprate were used, the coupling reaction proceeded in nearly quantitative yield within a minute, while the reaction rate and yield using the other labelled alkyl iodides varried considerably.The decay-corrected radiochemical yields of the 11C-labelled alkenes, fatty acids and aromatic compounds were 70-90, 15-55 and 98percent, respectively.The radiochemical purities were 94-99percent and the specific activity, as determined for toluene, was 880 MBq μmol-1.
Sulfur-containing phospholipid compounds and therapeutic compositions
-
, (2008/06/13)
Sulfur-containing phospholipid compounds of the formula STR1 pharmaceutical compositions having anti-tumor activity which include said phospholipid compounds, and the method of use for combating tumors, of said phospholipid compounds.
