- Squaraine-derived rotaxanes: Highly stable, fluorescent near-IR dyes
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Squaraines are fluorescent, near-IR dyes with promising photo-physical properties for biomedical applications. A limitation with these dyes is their inherent reactivity with nucleophiles, which leads to loss of the chromophore. Another drawback is their tendency to form nonfluorescent aggregates in water. Both problems can be greatly attenuated by encapsulating the dye inside an amide-containing macrocycle. In other words, the squaraine becomes the thread component in a Leigh-type rotaxane, a permanently in terlocked molecule. Two new rotaxanes are described: an analogue with four tri(ethyleneoxy) chains on the squaraine to enhance water solubility, and a rotaxane that has an encapsulating macrocycle with transposed carbonyl groups. An X-ray crystal structure of the latter rotaxane shows that the macrocycle provides only partial protection of the electrophilic cyclobutene core of the squaraine thread. The stabilities of each compound in various solvents, including serum, were compared with a commercially available cyanine dye. The squaraine rotaxane architecture is remarkably resistant to chemical and photochemical degradation, and likely to be very useful as a versatile fluorescent scaffold for constructing various types of highly stable, near-IR imaging probes.
- Arunkumar, Easwaran,Fu, Na,Smith, Bradley D.
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- Synthesis of glycol ethers and their use for intensification of oil recovery
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Monoalkyl ethers of ethylene and triethylene glycols were prepared and tested for intensification of oil recovery. The features of oil displacement with aqueous solutions of glycol ethers from bulk models of strata and the effect of glycol ethers on acid treatment of oil-saturated samples were examined. A correlation between the structure of ether and its performance was revealed. The interphase tension at the boundary between the aqueous solution of the glycol ether and kerosene was determined.
- Lebedeva,Mazaev,Tret'yakov
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- Effect of carboxylic acid on micelles of a neutral amphiphilic dendro-calix[4]arene
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An amphiphilic calix[4]arene bearing branched 3,4,5-tris(2-(2-(2- methoxyethoxy)ethoxy)ethoxy)benzamide groups at the upper rim was synthesized and could increase the solubility of naproxen and ibuprofen in water through hydrogen bonding and π-π stacking interactions. The interactions between amphiphilic calix[4]arene and carboxylic acids such as naproxen and ibuprofen could reverse the direction of the branched substituents and change the shape and size of calixarene micelles from solid to hollow or linear ones.
- Huang, Hong,Li, Dong-Mi,Wang, Weizhou,Chen, Yi-Chang,Khan, Khalid,Song, Song,Zheng, Yan-Song
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- Synthesis, characterization and spectroscopic properties of water soluble coumarins substituted with oligomeric alkoxy functions
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Novel water soluble robust fluorescent coumarins substituted with oligomeric alkoxy functions were synthesized by incorporating the Blaise reaction in the key step. Mono-methylated oligomeric polyethylene glycols were subjected to a three step protocol, namely (i) Michael addition to acrylonitrile, (ii) Blaise reaction with ethyl bromoacetate and (iii) condensation with 4-N,N-diethylamino-2-hydroxybenzaldehyde to give fluorescent water soluble coumarins. Water solubility of the coumarins increased with the number of oxygen atoms in the side chain. However, even the most water soluble coumarin in this series can be readily extracted out of water with organic solvents like dichloromethane or ethyl acetate. Both absorption and emission spectra, recorded in four solvents, namely, hexane (non-polar), ethyl acetate (moderately polar), methanol (polar protic) and water (highly polar and protic) displayed a bathochromic shift of the absorption (Δλmax ≈ 25 nm) and emission (Δλmax ≈ 57 nm) bands with increasing solvent polarity. The Δλmax of emission is more pronounced than the Δλmax of absorption, which indicates intramolecular charge-transfer (ICT) is less in the ground state compared to the excited state. Emission spectra recorded in these four solvents showed that fluorescent intensity is maximum in ethyl acetate.
- Surya Prakash Rao,Babu, Mohan,Desai, Avinash
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- Inclusion complexes of a new family of non-ionic amphiphilic dendrocalix[4]arene and poorly water-soluble drugs naproxen and ibuprofen
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The inclusion complexes of a new family of nonionic amphiphilic calix[4]arenes with the anti-inflammatory hydrophobic drugs naproxen (NAP) and ibuprofen (IBP) were investigated. The effects of the alkyl chain's length and the inner core of calix[4]arenes on the interaction of the two drugs with the calix[4]arenes were explored. The inclusion complexes of Amphiphiles 1a-c with NAP and IBP increased the solubility of these drugs in aqueous media. The interaction of 1a-c with the drugs in aqueous media was investigated through fluorescence, molecular modeling, and 1H-NMR analysis. TEM studies further supported the formation of inclusion complexes. The length of lipophilic alkyl chains and the intrinsic cyclic nature of cailx[4]arene derivatives 1a-c were found to have a significant impact on the solubility of NAP and IBP in pure water.
- Khan, Khalid,Lal Badshah, Syed,Ahmad, Nasir,Rashid, Haroon Ur,Mabkhot, Yahia
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supporting information
(2017/06/08)
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- Bis-TEGylated poly(p-benzamide)s: Combining organosolubility with shape persistence
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The synthesis of perfectly planar, bis-substituted aromatic polyamides is reported herein. With highly flexible triethylene glycol chains attached and conformational restriction through intramolecular, bifurcated hydrogen bonds these are among the most shape-persistent yet organo-soluble polymers to date. Starting from 4-nitrosalicylic acid, our group developed a route to phenyl-2,5-bis-TEGylated aminobenzoate, which could be polymerized by addition of lithium bis(trimethylsilyl)amide (LiHMDS). Since this technique has not been applied to step-growth polycondensations of polyaramides so far, the influence of two different solvents and an N-protective group was investigated. Therefore, substituted phenyl aminobenzoate derivatives carrying a free amine or an N-protective group have been polymerized. Additionally, the tendency for self-assembly of the readily soluble bis-TEGylated poly(p-benzamide) was observed by transmission electron microscopy (TEM) in the dried state. Dynamic light scattering (DLS) measurements of chloroform solutions did not indicate the formation of aggregates. Thus, intermolecular interactions, which other aromatic polyamides typically exhibit, are prevented. The access to bis-substituted, entirely rigid poly(p-benzamide)s via this new polycondensation method paves the way for exciting new structures in materials science and supramolecular chemistry.
- Schulze, Maren,Michen, Benjamin,Fink, Alke,Kilbinger, Andreas F. M.
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p. 5520 - 5530
(2013/08/23)
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- Antibacterial optimization of 4-aminothiazolyl analogues of the natural product GE2270 A: Identification of the cycloalkylcarboxylic acids
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4-Aminothiazolyl analogues of the antibiotic natural product GE2270 A (1) were designed, synthesized, and optimized for their activity against Gram positive bacterial infections. Optimization efforts focused on improving the physicochemical properties (e.g., aqueous solubility and chemical stability) of the 4-aminothiazolyl natural product template while improving the in vitro and in vivo antibacterial activity. Structure-activity relationships were defined, and the solubility and efficacy profiles were improved over those of previous analogues and 1. These studies identified novel, potent, soluble, and efficacious elongation factor-Tu inhibitors, which bear cycloalkylcarboxylic acid side chains, and culminated in the selection of development candidates amide 48 and urethane 58.
- Lamarche, Matthew J.,Leeds, Jennifer A.,Amaral, Kerri,Brewer, Jason T.,Bushell, Simon M.,Dewhurst, Janetta M.,Dzink-Fox, Joanne,Gangl, Eric,Goldovitz, Julie,Jain, Akash,Mullin, Steve,Neckermann, Georg,Osborne, Colin,Palestrant, Deborah,Patane, Michael A.,Rann, Elin M.,Sachdeva, Meena,Shao, Jian,Tiamfook, Stacey,Whitehead, Lewis,Yu, Donghui
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supporting information; experimental part
p. 8099 - 8109
(2012/01/30)
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- Synthesis and hydrolysis behavior of side-chain functionalized norbornenes
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The stabilities of various functionalized norbornenes that are monomers for the ring-opening metathesis polymerization (ROMP) in aqueous solution were evaluated toward hydrolysis under a range of temperatures (37, 60, and 80 °C) and pH values (3-9). All monomers contain hydrolyzable linkages to pendant functional groups, and conclusions were drawn relating to how the chemical diversity of these pendant functional groups, in accordance with the pH and temperature variations, affect hydrolysis of the aforementioned linkages. The hydrolysis was monitored by reverse phase HPLC analysis, and/or NMR spectroscopy. As expected, monomers containing ester linkages were fairly labile at higher pH values, while acetal-based linkers were cleaved at lower pH values. β-Amino ester groups experienced a significant increase in hydrolysis rate, while carboxylic acid-containing monomers did not follow any clear trend. Saccharide-containing monomers exhibited unique behaviors for various pH values and temperature ranges.
- Carlise, Joseph R.,Kriegel, Robert M.,Rees Jr., William S.,Weck, Marcus
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p. 5550 - 5560
(2007/10/03)
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- Biotinsilane compounds and a binding matrix containing these compounds
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The invention concerns a binding matrix containing a carrier material with an oxidic surface and a solid phase reactant covalently bound thereto via anchor groups which is capable of binding to at least one free reaction partner, which is characterized in that the solid phase reactant forms a diluted and essentially laterally homogeneous binding layer on the surface of the carrier material and that the anchor groups are silane groups and are linked to the solid phase reactant via a spacer molecule.
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- Process for preventing consolidation of p-dichlorobenzene
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A triethylene glycol derivative is added to p-dichlorobenzene so as to prevent consolidation and improve flowability of p-dichlorobenzene.
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- Process for producing m-phenoxybenzyl alcohol
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A process for producing m-phenoxybenzyl alcohol by reacting chlorobenzene with m-hydroxybenzyl alcohol in the presence of a copper catalyst and a base, the process being characterized by using an alkylene glycol as a reaction solvent.
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- Synthesis of Monodisperse Perfluoroalkyl-Oxyethylene Surfactants with Methoxy Capping: Surfactants of High Chemical Inertness
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Monodisperse fluoroalkyl non-ionic surfactants with a methoxy group capping the hydrophilic head, and having a high chemical inertness and surface properties typical of perfluorinated non-ionic surfactants, have been synthesized.
- Selve, Claude,Achilefu, Samuel
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p. 911 - 912
(2007/10/02)
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- AFFINITIES OF CROWN ETHERS, GLYMES, AND POLYAMINES FOR ALKALI PICRATES IN TOLUENE. APPLICATION OF POLYMER-SUPPORTED LINEAR POLYETHERS.
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This work reports the measurements of K values for polyamines, glymes, a few glycols (including that of a long-chain polyethylene glycol, carbowax 6000), and some frequently used cation-binding ligands as complexers of lithium or sodium picrate in toluene as solvent. K values for different resins obtained with the same soluble ligand provide a comparison of the effectiveness of these resins in binding ionic solutes.
- Xu,Smid
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p. 3790 - 3796
(2007/10/02)
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