6938-07-4Relevant articles and documents
Synthesis and evaluation of novel bone-targeting ibuprofen prodrug based on dendritic aspartic acid
Zhao, Yi,Zhao, Ze,Cui, Yamin,Chen, Changqing,Xie, Changwei,Yang, Yang
, p. 329 - 337 (2021/09/14)
Bone diseases, such as osteoarthritis, osteomyelitis, are notoriously difficult diseases to treat due to the comparatively low blood flows in bone tissue. Ibuprofen is a well-known potent non-steroid anti-inflammatory drug (NSAID), which plays an important role in the treatment of osteoarthritis. However, its poor bone-targeting ability hinders its further application. Herein, several novel dendritic aspartic acid-modified ibuprofen prodrugs were designed and further synthesized. The stability of these prodrugs was investigated in buffer solutions and plasma, respectively. In addition, the solubility, hydroxyapatite (HAP) binding, cytotoxicity, acute toxicity, and bone targeting ability in vivo were all evaluated. All the novel prodrugs showed the superior physicochemical property in vitro. The bone-targeting study in vivo provided the evidence that these prodrugs could increase ibuprofen levels in bone tissue, among which the Ibu-Asp8 showed the best affinity due to the increased aspartic acid residues conjugated to the drug. The dendritic Asp carriers were efficient as bone-targeting moieties, and the conjugation with ibuprofen ensured the increased accumulation of drugs in the bone region. In general, our findings provided a novel and effective drug for the treatment of bone diseases.
N-HETEROCYCLIC CARBENE (NHC) BASED LIGANDS AND RELATED METHODS
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Paragraph 0031, (2019/03/02)
Polydentate macrocyclic NHCs (NHC ligands) and related methods are disclosed. Such ligands advantageously facilitate a variety of ligand coordination modes and stabilize oxidation states of metal complexes with a number of coordination environments and shapes. The NHC ligands described herein comprise pendant groups configured to facilitate a variety of reactions including: cis-trans isomerization, proton shuttling and facilitating changes in coordination environments as a result of redox reactions.
Synthesis and structural characterization of 20-membered macrocyclic rings bearing: Trans -chelating bis(N-heterocyclic carbene) ligands and the catalytic activity of their palladium(ii) complexes
Thapa, Rajesh,Kilyanek, Stefan M.
, p. 12577 - 12590 (2019/08/26)
Macrocycles consisting of a 20-membered ring containing two imidazolium salt functionalities and of the formula [PhCH2N(CH2CH2CH2)Im(CH2CH2CH2)2][Br]2 (Im = imidazole = 3a, benzimidazole = 3b) were synthesized in 70-75% yields. These salts serve as precursors to macrocycles containing two N-heterocyclic carbene (NHC) moieties. Reaction of the macrocyclic salts 3a and 3b with silver oxide afforded macrocyclic-bis(NHC)silver(i) complexes 4a and 4b. Single-crystal X-ray diffraction studies of macrocyclic-bis(NHC)silver(i) complex 4a revealed a tetranuclear silver core with a short Ag-Ag distance (2.9328 ?). Complexes 4a and 4b serve as carbene transfer reagents to Pd. The treatment of macrocyclic-bis(NHC)silver(i) complexes 4a and 4b with one equivalent of PdCl2(MeCN)2 in methylene chloride afforded square-planar trans-macrocyclic-bis(NHC)Pd(ii)X2 complexes 5a and 5b. Preliminary screening of these palladium complexes showed they are competent precatalysts for Heck and Suzuki coupling reactions.
RECYCLABLE CATALYSTS FOR CHLORINATION OF ORGANIC ACIDS AND ALCOHOLS
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Paragraph 0063-0065, (2017/10/10)
The present invention discloses recyclable polymeric catalyst of Formula I, for chlorination of organic acids and alcohols using chlorinating agents such as carbonyl chloride, oxalyl chloride or thionyl chloride, wherein, ‘m’ on the pendent groups on polystyrene backbone can have values from 1 to 5 and R is the alkyl group ranging from C1 to C5.
Aza-Michael mono-addition using acidic alumina under solventless conditions
Bosica, Giovanna,Abdilla, Roderick
, (2016/07/07)
Aza-Michael reactions between primary aliphatic and aromatic amines and various Michael acceptors have been performed under environmentally-friendly solventless conditions using acidic alumina as a heterogeneous catalyst to selectively obtain the corresponding mono-adducts in high yields. Ethyl acrylate was the main acceptor used, although others such as acrylonitrile, methyl acrylate and acrylamide were also utilized successfully. Bi-functional amines also gave the mono-adducts in good to excellent yields. Such compounds can serve as intermediates for the synthesis of anti-cancer and antibiotic drugs.
O-benzenedisulfonimide as a reusable brnsted acid catalyst for hetero-michael reactions
Barbero, Margherita,Cadamuro, Silvano,Dughera, Stefano
, p. 758 - 767 (2013/01/15)
The hetero-Michael reactions among various oxygen, sulfur, and nitrogen nucleophiles and ,-unsaturated compounds were carried out in the presence of catalytic amounts of o-benzenedisulfonimide as Brnsted acid organocatalyst. The reaction conditions were very mild, and the yields of target products were good. The catalyst was easily recovered and purified, ready to be used in further reactions. This ability grants economic and ecological advantages. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
Synthesis of dendritic tryptophan derivatives and investigation on dendritic effects of their fluorescence and reactivity
He, Dongsheng,He, Gu,Guo, Li
, p. 454 - 460 (2012/04/10)
Two series of dendritic tryptophan derivatives have been synthesized and characterized, their emission spectra in different solvents and the reactivity of tryptophan were investigated and compared. There was a progressive shielding effect of the tryptophan in the emissive wavelengths of dendrimers increased with the size or generation of the dendritic shell.
New bidentate trans-chelating N-heterocyclic carbene ligands for palladium
Blakemore, James D.,Chalkley, Matthew J.,Farnaby, Joy H.,Guard, Louise M.,Hazari, Nilay,Incarvito, Christopher D.,Luzik, Eddie D.,Suh, Hee Won
experimental part, p. 1818 - 1829 (2011/06/24)
A family of imidazolium salts of the type [BnN(CH2CH 2CH2RIm)2]A·2[Cl] (Bn = CH2Ph; RIm = 1-methylimidazole (1a), 1-tert-butylimidazole (1b), 1-benzylimidazole (1c), 1-methylbenzimidazole (1d)), which contain a tertiary amine linking two imidazolium groups, has been synthesized. These imidazolium salts can be deprotonated with Ag2O to generate the Ag carbene complexes [{BnN(CH2CH2CH2 RIm)2}Ag].[AgCl2] (RIm = 1-methylimidazole (2a), 1-tert-butylimidazole (2b), 1-benzylimidazole (2c), 1-methylbenzimidazole (2d)). In the solid state 2d exists as an unusual tetramer, which consists of an [Ag2Cl4]2- core bridging two Ag(NHC) cations. Subsequent reaction of the Ag complexes with PdCl2(MeCN)2 generates Pd species of the type {BnN(CH 2CH2CH2RIm)2}PdCl 2 (RIm = 1-methylimidazole (3a), 1-tert-butylimidazole (3b), 1-benzylimidazole (3c), 1-methylbenzimidazole (3d)), which is a rare example of a family of Pd complexes that contain a bidentate trans-chelating N-heterocyclic carbene ligand. Compounds 3a and 3c were crystallographically characterized by X-ray crystallography and contain unusual 12-membered metallacycles. DFT calculations suggest that the preference for trans binding of the ligand is related to conformational effects of the linker. Compound 3b reacts with excess MeI to form {BnN(CH2CH2CH 2tBuIm)2}PdI2 (5b), a reaction in which we believe a Pd(IV) intermediate is generated. Compound 5b was crystallographically characterized. Compounds 3a-d are all active catalysts for the Heck reaction, and 3a can also catalyze the Suzuki reaction.
Synthesis and characterization of N-substitutional ethylenediamine derivatives
Yao, Ri-Sheng,Jiang, Lai-En,Wu, Sheng-Hua,Deng, Sheng-Song,Yang, Yang
experimental part, p. 3792 - 3794 (2012/01/05)
N-Substituted and N,N-disubstituted ethylenediamine derivatives were prepared rapidly in aqueous conditions from 30 to 76 % yields, respectively, on a multi-gram scale starting from inexpensive and commercially available starting materials. The steps involved Michael addition, hydrazinolysis and Curtius rearrangements. The highlight of this method lies on its convenience and economy in accessing these intermediates.
Bone targeting prodrugs based on peptide dendrimers, synthesis and hydroxyapatite binding in vitro
Ouyanga, Liang,Huang, Wencai,Hea, Gu,Guo, Li
experimental part, p. 272 - 277 (2010/04/23)
Novel bone targeting naproxen prodrugs with poly(aspartic acid) moieties and with two and three poly(aspartic acid) sequences peptide dendrimers were synthesized using a conventional method. The modified naproxen conjugates were incubated with hydroxyapatite in PBS at physiological conditions over 16h. The study revealed the hydroxyapatite binding properties of poly(aspartic acid) and it was found that the peptide dendrimer prodrugs exhibited a faster initial binding and a greater total binding. The obtained binding data in vitro indicated that the peptide dendrimers with poly(aspartic acid) sequences were useful for the development of new bone targeting molecules for drug delivery to bone.
