121986-07-0Relevant articles and documents
Three-Dimensional Heterometallic Coordination Networks: Syntheses, Crystal Structures, Topologies, and Heterogeneous Catalysis
Srivastava, Sumit,Aggarwal, Himanshu,Gupta, Rajeev
, p. 4110 - 4122 (2015)
This work presents the synthesis of {Co3+-Zn2+} and {Co3+-Cd2+} heterometallic coordination networks. These networks are originated from two unique Co3+-based metalloligands containing appended arylcarboxylic acid groups at the strategically placed positions. Such appended arylcarboxylate groups coordinate the secondary metal ions, Zn2+ and Cd2+, to afford distinct three-dimensional networks. All four networks display orderly arrangement of secondary metal ions and unique network topologies including an unprecedented one. These networks have been shown to act as the heterogeneous and reusable catalysts for the Knoevenagel condensation reactions and cyanation reactions of assorted aldehydes. Cyanation reactions nicely demonstrate the substrate size-exclusion catalysis.
Two-dimensional rhombus grid coordination polymer showing heterogeneous catalytic activities
Sharma, Manish K.,Singh, Prabal P.,Bharadwaj, Parimal K.
, p. 6 - 10 (2011)
A coordination polymer, {[Cd(L)2(DMF)2] ·(ClO4)2·(2DMF)}n (1) (L = bis-(4-imidazol-1-yl-phenyl)-diazene) has been synthesized at room temperature. The polymer forms a two-dimensional (2D) rhombus-grid sheet structure. These 2D sheets are stacked in ABAB... mode with an inter-planar spacing of 3.729 . Each Cd(II) ion is equatorially bonded to four imidazole N atoms belong to four different ligand units while O atoms from two DMF molecules occupy the axial sites. Two ClO4- counter anions as well as two DMF molecules occupy the void space in each rhombus grid. This compound catalyzes cyanosilylation reactions of aromatic aldehydes in dichloromethane under mild conditions in heterogeneous fashion. On heating 1 at 120 °C for 4 h, all DMF molecules are lost and the ClO4- anions move out of the void space to occupy the axial sites on the metal to yield, de-solvated {[Cd(L)2(ClO4)2]}n (1) without losing crystallinity. De-solvated 1 exhibits heterogeneous catalytic activity in several Knoevenagel condensation reactions at RT.
ADDITION OF CYANIDE IONS TO AROMATIC ALDEHYDES: A COMPETITION METHOD FORM THE DETERMINATION OF EQUILIBRIUM CONSTANTS OF NUCLEOPHILIC ADDITION REACTIONS
Gold, Victor,Wassef, Wasfy N.
, p. 1431 - 1434 (1984)
The equilibrium concentration of the cyanide Meisenheimer adduct of 1,3,5-trinitrobenzene formed potassium cyanide-18-crown-6 and trinitrobenzene, in DMSO solution, is reduced in the presence of an aromatic aldehyde, with an accompanying decrease in the absorbance ot the solution due to the intensely coloured Meisenheimer adduct.Equilibrium constants have accordingly been determined for the formation of the cyanide Meisenheimer adduct of trinitrobenzene and for the formation of members of a series of substituted benzaldehyde cyanohydrin anions in dimethyl sulphoxide solution.
Postfunctionalized Metalloligand-Based Catenated Coordination Polymers: Syntheses, Structures, and Effect of Labile Sites on Catalysis
Pandey, Saurabh,Kumar, Girijesh,Gupta, Rajeev
, p. 2723 - 2735 (2019)
In this work, pyridyl-appended Co3+ complexes (1 and 2) have been postfunctionalized by using 4-(bromomethyl)benzoic acid, thus changing the functionalities from pyridyl-N donors to carboxylate-O donors. Using two such postfunctionalized metalloligands (3 and 4), several homo and heterometallic coordination polymers (HCPs) have been synthesized. Single crystal structural analyses revealed that all HCPs presented intriguing one-dimensional catenated architectures. Postsynthetic modification induced flexibility was found to be responsible for the nearly identical architectures for two sets of HCPs starting from two different postfunctionalized metalloligands, 3 and 4. Two sets of HCPs differed by the presence (3a-3d) or absence (4a-4b) of labile coordinated water molecules that demonstrated a profound effect on the heterogeneous catalysis of Knoevenagel condensation reactions and cyanation reactions.
An efficient cyanosilylation of aldehydes with trimethylsilyl cyanide catalysed by MgI2 etherate
Wang, Yanping,Feng, Meiling,Liu, Yingshuai,Zhang, Xingxian
, p. 566 - 567,2 (2012)
A convenient procedure for the synthesis of cyanohydrins by the addition of trimethylsilyl cyanide to aromatic aldehydes, heteroaromatic aldehydes, aliphatic aldehydes and unsaturated aldehydes catalysed by MgI2 etherate (MgI2(OEt2)n) in good to excellent yields is described.
Highly chemoselective and efficient Strecker reaction of aldehydes with TMSCN catalyzed by MgI2 etherate under solvent-free conditions
He, Kailun,Liu, Huijun,Zhang, Xingxian,Zhou, Jing
supporting information, p. 933 - 936 (2019/03/08)
Strecker reaction of various substituted aromatic aldehydes, heteroaromatic aldehydes, aliphatic aldehydes and α,β-unsaturated aldehydes with trimethylsilyl cyanide (TMSCN) was realized in the presence of 5 mol % of MgI2 etherate in a mild, efficient and highly chemoselective manner under solvent-free conditions.
SELF-IMMOLATIVE LINKERS CONTAINING MANDELIC ACID DERIVATIVES, DRUG-LIGAND CONJUGATES FOR TARGETED THERAPIES AND USES THEREOF
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Page/Page column 54; 94, (2015/03/28)
The invention provides a therapeutic drug and targeting conjugate, pharmaceutical compositions containing these conjugates in pharmaceutical composition, and uses of these conjugates in anti-neoplastic and other therapeutic regimens. Also provided are novel intermediates thereof. The conjugates provide a therapeutic drug fragment or prodrug fragment bound to a targeting moiety via a linker which comprises a substrate cleavable by a protease such as Cathepsin B. The targeting moiety is a ligand which targets a cell surface molecule, such as a cell surface receptor on an anti-neoplastic cell. The ligand may function solely as a targeting moiety or may itself have a therapeutic effect. Following administration of the therapeutic drug and targeting conjugate of formula I and exposure of the conjugate to the protease specific for the substrate, the linker is cleaved and the targeting moiety is separated from the conjugate, which causes the drug fragment or prodrug fragment to convert to the drug or prodrug. The recited conjugates are useful in anti-neoplastic therapies. Also provided are methods of making the therapeutic drug and targeting conjugates and intermediates thereof, and kits comprising the therapeutic drug and targeting conjugates.
A metalloligand appended with thiazole rings: Heterometallic {Co3+-Zn2+} and {Co3+-Cd2+} complexes and their heterogeneous catalytic applications
Bansal, Deepak,Hundal, Geeta,Gupta, Rajeev
, p. 1022 - 1032 (2015/06/24)
This work describes a Co3+-based metalloligand containing appended thiazole rings and its reactions with secondary metal ions to produce heterometallic {Co3+-Zn2+} and {Co3+-Cd2+} complexes. Structural studies show that some of the appended thiazole rings from the metalloligand coordinate to secondary metal ions, whereas the remaining ones act as hydrogen-bond acceptors to metal-bound CH3OH or H2O molecules. These heterometallic complexes function as reusable heterogeneous catalysts for the ring-opening reactions of epoxides as well as cyanation and Knoevenagel condensation reactions of aldehydes. The catalytic results illustrate that the microenvironment remains intact during the catalysis and potentially enhances the substrate interaction with the Lewis acidic secondary metal ions.
Mechanism-Based inactivation of human cytochrome p450 3A4 by two piperazine-Containing compounds
Bolles, Amanda K.,Fujiwara, Rina,Briggs, Erran D.,Nomeir, Amin A.,Furge, Laura Lowe
, p. 1471 - 1475 (2014/12/11)
Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of more than half of pharmaceutic drugs, and inactivation of CYP3A4 can lead to adverse drug-drug interactions. The substituted imidazole compounds 5-fluoro-2-[4-[(2-phenyl-1H-imidazol-5-yl) methyl]-1-piperazinyl]pyrimidine (SCH 66712) and 1-[(2-ethyl-4-methyl-1H-imidazol-5-yl)methyl]-4-[4-(trifluoromethyl)-2-pyridinyl]piperazine (EMTPP) have been previously identified as mechanism-based inactivators (MBI) of CYP2D6. The present study shows that both SCH 66712 and EMTPP are also MBIs of CYP3A4. Inhibition of CYP3A4 by SCH 66712 and EMTPP was determined to be con-centration, time, and NADPH dependent. In addition, inactivation of CYP3A4 by SCH 66712 was shown to be unaffected by the presence of electrophile scavengers. SCH 66712 displays type I binding to CYP3A4 with a spectral binding constant (Ks) of 42.9 ± 2.9 μM. The partition ratios for SCH 66712 and EMTPP were 11 and 94, respectively. Whole protein mass spectrum analysis revealed 1:1 binding stoichiometry of SCH 66712 and EMTPP to CYP3A4 and a mass increase consistent with adduction by the inactivators without addition of oxygen. Heme adduction was not apparent. Multiple monooxygenation products with each inactivator were observed; no other products were apparent. These are the first MBIs to be shown to be potent inactivators of both CYP2D6 and CYP3A4.
Mononuclear complexes of amide-based ligands containing appended functional groups: Role of secondary coordination spheres on catalysis
Bansal, Deepak,Kumar, Gulshan,Hundal, Geeta,Gupta, Rajeev
, p. 14865 - 14875 (2015/02/19)
Amide-based ligands H2L1, H2L2 and H2L3 containing thiazole, thiazoline and benzothiazole appended groups have been used to synthesize Zn2+ (1 and 3), Cd2+ complexes (2 and 4), and a Mn2+ complex (5). In all cases, potentially multidentate ligands create a meridional N3 coordination environment around the M(ii) ion whereas additional sites are occupied by labile nitrate ions in 1-4 and MeOH in 5. Interestingly, metal complexation caused the migration of protons from amidic N-H sites to the appended heterocyclic rings in complexes 1-4. Structural studies show that the protonated heterocyclic rings in these complexes create a hydrogen bond based cavity adjacent to the metal ion. Importantly, binding studies confirm that the substrates are bound within the complex cavity closer to the Lewis acidic metal in all complexes including the oxidation-sensitive Mn ion in complex 5. All complexes have been utilized as the reusable and heterogeneous catalysts for ring-opening reactions of assorted epoxides, cyanation reactions of various aldehydes, and epoxidation reactions of several olefins. This journal is
