6320-72-5Relevant academic research and scientific papers
Comparison of affinity ranking by target-directed dynamic combinatorial chemistry and surface plasmon resonance
Frei, Priska,Silbermann, Marleen,Mühlethaler, Tobias,Jiang, Xiaohua,Schwardt, Oliver,Hevey, Rachel,Ernst, Beat
, p. 143 - 167 (2019)
Target-directed dynamic combinatorial chemistry (tdDCC) is a powerful method to screen ligands for pharmacologically relevant targets. Generating a dynamic library from reversibly reacting building blocks in the presence of a target protein leads to the a
A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
Inaloo, Iman Dindarloo,Majnooni, Sahar
, p. 6359 - 6368 (2019/11/05)
A palladium-catalyzed domino method for the direct synthesis of carbamates and ureas has been developed by using readily available and economical starting materials (aryl halide, carbon monoxide, sodium azide, amines and alcohols) in a one-pot approach. The domino process underwent carbonylation, Curtius rearrangement, and nucleophilic addition. This protocol provides a step-economical and highly efficient reaction to access the wide range of valuable carbamates, symmetrical and unsymmetrical ureas with high yields under remarkable mild reaction conditions that are important factors in pharmaceutical science, biochemistry and agricultural industries. Furthermore, the magnetically recoverable nanocatalyst (Fe3O4?SiO2/Pd(II)) can be conveniently and swiftly recycled using external magnet and reused at least for seven times without noticeable loss of its catalytic activity.
CERAMIDE GALACTOSYLTRANSFERASE INHIBITORS FOR THE TREATMENT OF DISEASE
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Paragraph 0001268; 0001269, (2018/01/17)
Described herein are compounds, methods of making such compounds, pharmaceutical compositions and medicaments containing such compounds, and methods of using such compounds to treat or prevent diseases or disorders associated with the enzyme ceramide galactosyltransferase (CGT), such as, for example, lysosomal storage diseases. Examples of lysosomal storage diseases include, for example, Krabbe disease and Metachromatic Leukodystrophy.
Anilinolysis of reactive aryl 2,4-dinitrophenyl carbonates: Kinetics and mechanism
Castro, Enrique A.,Domecq, Claudia,Santos, Jose G.
supporting information; experimental part, p. 191 - 197 (2011/10/04)
The reactions of a series of anilines with phenyl 2,4-dinitrophenyl (1), 4-nitrophenyl 2,4-dinitrophenyl (2), and bis(2,4-dinitrophenyl) (3) carbonates are subjected to a kinetic investigation in 44 wt% ethanol-water, at 25.0 ± 0.1°C and an ionic strength of 0.2 M. Under amine excess pseudo-first-order rate coefficients (kobs) are obtained. Plots of kobs against free amine concentration at constant pH are linear, with slopes kN. The BrAnsted plots (log kN vs. anilinium pKa) for the anilinolysis of 1-3 are linear, with slope (β) values of 0.52, 0.61, and 0.63, respectively. The values of these slopes and other considerations suggest that these reactions are ruled by a concerted mechanism. For these reactions, the kN values follow the reactivity sequence: 3 > 2 > 1. Namely, the reactivity increases as the number of nitro groups attached to the nonleaving group increases. Comparison of the reactions of this work with the stepwise pyridinolysis of carbonates 1-3 indicates that the zwitterionic tetrahedral intermediate (T±) formed in the pyridinolysis reactions is destabilized by the change of its pyridino moiety by an isobasic anilino group. This is attributed to the superior leaving ability from the T± intermediate of anilines, relative to isobasic pyridines, which destabilize kinetically this intermediate. The kN values for the anilinolysis of carbonates 1-3 are similar to those found in the reactions of these carbonates with secondary alicyclic amines. With the kinetic data for the anilinolysis of the title substrates and 4-methylphenyl and 4-chlorophenyl 2,4-dinitrophenyl carbonates, a multiparametric equation is derived for log kN as a function of the pKa of the conjugate acids of anilines and nonleaving groups.
Novel and efficient synthesis of 4-substituted-1,2,4-triazolidine-3,5- diones from anilines
Mallakpour, Shadpour,Rafiee, Zahra
, p. 1927 - 1934 (2008/02/04)
A simple and efficient three-step synthetic procedure for the preparation of 4-substituted phenyl derivatives of 1,2,4-triazolidindiones (urazoles), starting from anilines, has been developed. In this method, aniline derivatives were reacted with 4-nitrophenyl chloroformate to provide corresponding carbamate derivatives. In the second step, semicarbazide derivatives were prepared from these carbamates by reaction with ethyl carbazate. The cyclization reaction of corresponding semicarbazides furnished 1,2,4-triazolidindiones in high yields. Copyright Taylor & Francis Group, LLC.
A novel naphthylmethyleneimino-type photocleavable protecting group for primary amines
Igarashi, Tetsutaro,Shimokawa, Masaru,Iwasaki, Miyuki,Nagata, Kensaku,Fujii, Masato,Sakurai, Tadamitsu
, p. 1436 - 1440 (2008/02/13)
A novel naphthylmethyleneimino-type protecting group for aliphatic and aromatic primary amines including α-amino acids was devised and its introduction was accomplished in good to excellent yields. This type of protecting group was found to be cleanly removed photochemically to regenerate the primary amines in good to high yields, regardless of steric and electronic properties. Georg Thieme Verlag Stuttgart.
4-[18F]fluorophenyl ureas via carbamate-4-nitrophenyl esters and 4-[18F]fluoroaniline
Olma, Sebastian,Ermert, Johannes,Coenen, Heinz H.
, p. 1037 - 1050 (2007/10/03)
Four different no carrier added (n.c.a.) 4-[18F]fluorophenylurea derivatives are synthesized as model compounds via two alternative routes. In both cases carbamate-4-nitrophenylesters are used as intermediates. Either n.c.a. 4-[18F]fluoroaniline reacts with carbamates of several amines, or the carbamate of n.c.a. 4-[18F]fluoroaniline is formed at first and an amine is added subsequently to yield the urea derivative. The choice of the appropriate way of reaction depends on the possibilities of precursor synthesis. The radiochemical yields reach up to 80% after 50 min of synthesis time while no radiochemical by-products can be determined. These high yields were possible due to an optimized preparation of n.c.a. 4-[18F] fluoroaniline with a radiochemical yield of up to 90%. From the various ways of its radiosynthesis, the substitution with n.c.a. [18F]fluoride on dinitrobenzene is chosen, using phosphorous acid and palladium black for reduction of the second nitro group. Copyright
Nucleophilic substitution reactions of phenyl chloroformates
Yew, Kyoung Han,Koh, Han Joong,Lee, Hai Whang,Lee, Ikchoon
, p. 2263 - 2268 (2007/10/03)
Methanolysis and aminolysis of phenyl chloroformates in acetonitrile have been investigated.The rates are slow due to initial-state stabilization by strong resonance electron donation from the phenoxy group.In both reactions the large positive values of ρY = 0.8-1.6 and low ΔH(excit.) and ΔS(excit.) values show that the transition state is strongly associative with little bond breaking.This mechanism is supported by the relatively large solvent isotope effect, kMeOH/kMeOD = ca. 2.3-2.5, and by the relatively strong inverse secondary kinetic isotope effect, kH/kD =/ca. 0.74-0.94, involving deuteriated aniline nuclephiles, in addition to a negative value of ρXY.The dependence on aniline basicity, βx(βnuc) =/ca. 0.8, and the ρX values of -2.3 are similar to those corresponding values for the reactions of benzoyl chlorides which have been predicted to react by an associative SN2 mechanism.These observations are consistent with a concerted displacement mechanism for the methanolysis and aminolysis of phenyl chloroformates.
A New Convenient Method for the Synthesis of Symmetrical and Unsymmetrical N,N'-Disubstituted Ureas
Izdebski, Jan,Pawlak, Danuta
, p. 423 - 425 (2007/10/02)
A new method is described for the preparation of symmetrically and unsymmetrically disubstituted ureas by aminolysis of bis(4-nitrophenyl) carbonate.The second substitution is slower than the first one, and it is possible to isolate monosubstituted intermediates when equimolar amounts of substrates are used.The reaction of the intermediates with different amines give unsymmetrical derivatives of urea.
Carbonic anhydrase catalyzed hydrolysis and decarboxylation. Kinetic studies of enzyme catalyzed decomposition of mono- and disubstituted derivatives of carbonic acid
Pocker,Guilbert
, p. 70 - 78,71,75 (2007/10/13)
The effect of bovine carbonic anhydrase on the stepwise hydrolysis of carbonate diesters is examined. While biphasic enzyme kinetics cannot be detected in the case of bis(4 nitrophenyl) carbonate, it is demonstrated that at pH 10.45 methyl 4 nitrophenyl carbonate is enzymatically hydrolyzed to produce an intermediate monoester, methyl carbonate, which does not undergo enzyme catalyzed decarboxylation. However, it is shown that at pH 7.27 methyl carbonate decarboxylation is accelerated by carbonic anhydrase. The enzymatic pH rate profile for methyl 4 nitrophenyl carbonate release of 4 nitrophenol rises with increasing pH, while the pH dependency for the enzyme catalyzed decarboxylation of methyl carbonate is such that it decreases with increasing pH. In this respect, the kinetic behavior of bovine carbonic anhydrase in regard to methyl 4 nitrophenyl carbonate hydrolysis appears to be similar to that observed in CO2 hydration; in both the rate varies as though dependent on the ionization of a group in the enzyme with pK near 7, only the basic form being active. On the other hand the enzyme catalyzed decarboxylation of methyl carbonate appears to be formally similar to that of bicarbonate; with these two anions the rate varies as though dependent on the ionization of a group in the enzyme of essentially the same pK(7) with only the acid form being active. Although at pH 7.27 the first order rate coefficient, k(buf), for methyl carbonate decomposition is 1.8 times larger than that for bicarbonate dehydration, the second order enzymatic rate coefficient, k(enz), for bicarbonate is three orders of magnitude greater than that for methyl carbonate. The large differences in these k(enz) values are discussed in terms of the role of the labile bicarbonate proton in the mechanism of carbonic anhydrase catalysis.
