176-32-9Relevant articles and documents
Acidic properties of sulfonic acid-functionalized FSM-16 mesoporous silica and its catalytic efficiency for acetalization of carbonyl compounds
Shimizu, Ken-Ichi,Hayashi, Eidai,Hatamachi, Tsuyoshi,Kodama, Tatsuya,Higuchi, Tomoya,Satsuma, Atsushi,Kitayama, Yoshie
, p. 131 - 138 (2005)
Propyl-sulfonic acid-functionalized FSM-16 mesoporous silica (SO 3H-FSM) is prepared by a conventional post-modification method. For the acetalization of carbonyl compounds with ethylene glycol, SO 3H-FSM shows a higher rate and 1,3-dioxolane yield than conventional heterogeneous solid acids such as zeolites, montmorillonite K10 clay, silica-alumina, and the sulfonic resin. SO3H-FSM is stable during the reaction, with no leaching and deactivation of sulfonic acid groups, and is reusable without loss of its activity. The acidity and hydrophilicity of SO 3H-FSM are well characterized by the microcalorimetry of NH 3 adsorption, NH3-TPD, and H2O-TPD, and the result is compared with those for various aluminosilicate zeolites (HZSM5, HBEA, HY) and K10 clay. It is found that NH3-TPD is not suitable for characterizing the acidity of SO3H-FSM, because the decomposition of SO3H groups on SO3H-FSM begins above 200°C. An NH 3 adsorption microcalorimetric experiment at 150°C shows that, compared with HZSM5, SO3H-FSM has a smaller number of acid sites but has a similar number of strong acid sites with ammonia adsorption heat above 140 kJ mol-1. Comparison of the structural properties and catalytic results shows that a large pore diameter and low hydrophilicity are required to obtain high activity. Bronsted acid sites with a relatively strong acid strength are more suitable for this reaction, but the high acid concentration is not indispensable. The high activity of SO3H-FSM should be caused by the presence of the strong Bronsted acid sites in the mesopore with a relatively low hydrophilicity, where both reactants can smoothly access the acid sites.
Highly efficient heterogeneous acetalization of carbonyl compounds catalyzed by a titanium cation-exchanged montmorillonite
Kawabata, Tomonori,Mizugaki, Tomoo,Ebitani, Kohki,Kaneda, Kiyotomi
, p. 8329 - 8332 (2001)
The titanium cation-exchanged montmorillonite efficiently catalyzed the selective acetalization of various carbonyl compounds as a recyclable solid acid. This heterogeneous catalyst has an advantage of a strikingly simple workup procedure over conventional homogeneous acids.
Correlation between 13C and 17O chemical shifts and torsional strain in spiroacetals
Guerrero-Alvarez, Jorge Antonio,Ariza-Castolo, Armando
, p. 795 - 798 (2007)
The relationship between the 13C and 17O NMR chemical shifts and the dihedral energies (non-bonding interactions) of 1,4-dioxaspiro[4.4]nonane, 1,4-dioxa- and 6,10-dioxaspiro[4.5]decane, 1,4-dioxa- and 6,11-dioxaspiro[4.6]undecane, 1,5-dioxaspiro[5.5]undecane, 1,5-dioxa and 7,12-dioxaspiro[5.6]dodecane and 1,6-dioxaspiro[6.6]tridecane were analyzed. These data showed correlation of the non-bonding interactions with the chemical shift of the spiranic carbon, as well as a linear relationship between 13C and 17O.
Thermochemical properties of iodinated cubane derivatives
Griffiths, Justin R.,Tsanaktsidis, John,Savage, G. Paul,Priefer, Ronny
, p. 15 - 20 (2010)
Since the initial synthesis of cubane, numerous derivatives have been made with a diverse range of physical, chemical, and biological properties. Some iodinated cubane derivatives have been reported to be thermolytically unstable and/or rearrange in situ. An iodinated cubane-containing, norbornene-based polymer showed rapid thermo-decomposition during TGA studies. Bis-(4-iodocubylmethyl)-dialkoxy disulfide undergoes fragmentation more easily than its non-iodinated counterpart. The synthesis and thermal behaviour of a library of iodinated cubane compounds are herein reported. Most of the iodinated cubane derivatives showed melting/decomposition with no exotherm upon cooling. 4-Iodo-1-vinylcubane was observed to rearrange to 4-vinyl-trans-β-iodostyrene and its cyclooctatetraene intermediate during DSC analysis. TGA studies on 1-iodo-4-(hydroxymethyl)-cubane suggest that this particular iodinated cubane scaffold is mostly prone to rapid thermo-decomposition.
Microwave-assisted acetalization of carbonyl compounds catalyzed by reusable Envirocat supported reagents
Beregszaszi, Timea,Molnar, Arpad
, p. 3705 - 3709 (1997)
Envirocat supported reagents (EPZG, EPZ10, and EPIC) are found to efficiently catalyze the acetalization of carbonyl compounds with 1,2-ethanediol under microwave irradiation under solvent-free conditions. The reagents can be used in repeated experiments to perform the reaction with the same activity.
Cubane Arrives on the Cucurbituril Scene
Jelínková, Kristyna,Surmová, Heda,Matelová, Alena,Rouchal, Michal,Prucková, Zdeňka,Dastychová, Lenka,Ne?as, Marek,Vícha, Robert
supporting information, p. 2698 - 2701 (2017/05/24)
Cubane, an intriguing chemical curiosity first studied in the early 1960s, has become a valuable structural motif and has recently been involved in the structures of a great number of prospective compounds. The first dicationic supramolecular guest 5 is prepared and derived from a 1,4-disubstituted cubane moiety, and its binding behavior toward cucurbit[n]urils (CBn) and cyclodextrins (CD) is studied. The bisimidazolium salt 5 forms 1:1 inclusion complexes with CB7, CB8, and β-CD with the respective association constants (6.7 ± 0.5) × 1011 M-1, (1.5 ± 0.2) × 109 M-1, and 2 M-1 in water. The solid-state structures of the 5@CB7 and 5@CB8 complexes are also reported.
Structure-activity relationships of N-substituted 4-(trifluoromethoxy) benzamidines with affinity for GluN2B-containing NMDA receptors
Beinat, Corinne,Banister, Samuel D.,Hoban, Jane,Tsanaktsidis, John,Metaxas, Athanasios,Windhorst, Albert D.,Kassiou, Michael
supporting information, p. 828 - 830 (2014/02/14)
GluN2B subtype-selective NMDA antagonists represent promising therapeutic targets for the symptomatic treatment of multiple CNS pathologies. A series of N-benzyl substituted benzamidines were synthesised and the benzyl ring was further replaced with various polycyclic moieties. Compounds were evaluated for activity at GluN2B containing NMDA receptors where analogues 9, 12, 16 and 18 were the most potent of the series, replacement of the benzyl ring with polycycles resulted in a complete loss of activity.
