192070-90-9Relevant academic research and scientific papers
Versatile and efficient synthesis of a new class of aza-based phosphinic amide ligands via unusual P-C cleavage
Tsai, Shih-Chung,Fu, Yaw-Shien,Liao, Ju-Hsiou,Yu, Shuchun Joyce
, p. 3007 - 3017 (2006)
A new class of bidentate, aza-based phosphinic amide ligands of the type RN(H)P(=O)(2-py)2 (2-py=2-pyridyl) was synthesized within minutes via a one-pot process including Staudinger reaction of an organic azide (RN 3) with 2-pyridylphosphines, followed by partial, unprecedented hydrolysis under loss of one aromatic substituent. The structure of the unusual-hydrolysis product H2C=CH(CH2)9N(H)P(= O)(2-py)2 (5a) was characterized by IR, 1H- and 31P-NMR, as well as by X-ray crystal-structure analysis (Figure). The tetrahedral P-atom was found to be surrounded by a trigonal-pyramidal arrangement of the substituents. To gain insight into the formation of these novel phosphinic amides, a series of intermediate iminophosphoranes, H 2C=CH(CH2)9N=P(Ar)n(2-py) 3-n (n = 0-3), compounds 1a-1f, were synthesized, and their hydrolyses were studied. All tested compounds followed the classical hydrolysis route of P=N cleavage under acidic conditions. Sequential hydrolysis to 5a-5d only occurred under either basic conditions or in wet MeCN as solvent. Notably, H2C=CH(CH2)9N=P(C6H 5)(4-MeO-2-py)2 (1c) was hydrolyzed at a much slower rate compared to its analogue 1b lacking the MeO group. On the contrary, the halogenated compounds H2C=CH(CH2)9N=P(4-X- C6H4)3 (1f,g) (X = F, Cl) were hydrolyzed at a notably faster rate relative to the non-halogenated congener 1e (X = H).
Instability of Surface-Grafted Weak Polyacid Brushes on Flat Substrates
Galvin, Casey J.,Bain, Erich D.,Henke, Adam,Genzer, Jan
, p. 5677 - 5687 (2015)
We study the stability of weak polyacid brush (WPAB) gradients in aqueous media covering a range in grafting density (σ) spanning 0.05-0.5 chains/nm2 using two analogous surface-anchored bromoisobutyrate-based initiators for atom transfer radical polymerization (ATRP) bearing either an ester or amide linker. Variations in dry thickness of ester-based WPABs as a function of time and pH are consistent with WPAB degrafting via linker hydrolysis catalyzed by mechanical tension in the grafted chains. Sources of tension considered include high σ, as well as swelling and electrostatic repulsion associated with increasing degree of deprotonation (α) of repeat units in the WPAB. Normalized thickness of the WPAB decreases by a maximum amount at intermediate σ between ~0.05-0.15 chains/nm2, implying that contributions to tension by α are counterbalanced by charge regulation in the WPAB at high σ. Amide-based WPABs are more stable up to 264 h incubation, suggesting that commonly used ester-bearing ATRP initiators are more susceptible to hydrolysis over the time scales examined. (Figure Presented).
Poly(phosphorodiamidate)s by Olefin Metathesis Polymerization with Precise Degradation
Steinmann, Mark,Wagner, Manfred,Wurm, Frederik R.
, p. 17329 - 17338 (2016)
Degradable polymers are a currently growing field of research for biomedical and materials science applications. The majority of such compounds are based on polyesters and polyamides. In contrast, their phosphorus-containing counterparts are much less studied, in spite of their potential precise degradation profile and biocompatibility. Herein, the first library of poly(phosphorodiamidate)s (PPDAs) with two P?N bonds forming the polymer backbone and a pendant P?OR group is prepared through acyclic diene metathesis polymerization. They are designed to vary in their hydrophilicity and are compared with the structural analogues poly(phosphoester)s (PPEs) with respect to their thermal properties and degradation profiles. The degradation of PPDAs can be controlled precisely by the pH: under acidic conditions the P?N linkages in the polymer backbone are cleaved, whereas under basic conditions the pendant ester is cleaved selectively and almost no backbone degradation occurs. The PPDAs exhibit distinctively higher thermal stability (from thermogravimetric analysis (TGA)) and higher glass transition and/or melting temperatures (from differential scanning calorimetry (DSC)) compared with analogous PPEs. This renders this exotic class of phosphorus-containing polymers as highly promising for the development of future drug carriers or tissue engineering scaffolds.
Stereochemical effects of chiral monolayers on enhancing the resistance to mammalian cell adhesion
Bandyopadhyay, Debjyoti,Prashar, Deepali,Luk, Yan-Yeung
, p. 6165 - 6167 (2011)
This work describes the different durations of surface confinement of adhered mammalian cells by monolayers comprised of enantiomers of bio-inert polyol-terminated alkanethiols. Enhanced resistance to protein adsorption and cell adhesion is obtained on monolayers formed by a racemic mixture of the enantiomeric alkanethiols.
Liposomal FRET Assay Identifies Potent Drug-Like Inhibitors of the Ceramide Transport Protein (CERT)
Aglar, ?znur,Arenz, Christoph,Banhart, Sebastian,Cong, Xiaojing,Hamdo, Housam H.,Heuer, Dagmar,Kleuser, Burkhard,M?ller, Heiko M.,Saied, Essa M.,Samaha, Doaa,Schumacher, Fabian
supporting information, p. 16616 - 16621 (2020/11/30)
Ceramide transfer protein (CERT) mediates non-vesicular transfer of ceramide from endoplasmic reticulum to Golgi apparatus and thus catalyzes the rate-limiting step of sphingomyelin biosynthesis. Usually, CERT ligands are evaluated in tedious binding assays or non-homogenous transfer assays using radiolabeled ceramides. Herein, a facile and sensitive assay for CERT, based on F?rster resonance energy transfer (FRET), is presented. To this end, we mixed donor and acceptor vesicles, each containing a different fluorescent ceramide species. By CERT-mediated transfer of fluorescent ceramide, a FRET system was established, which allows readout in 96-well plate format, despite the high hydrophobicity of the components. Screening of a 2 000 compound library resulted in two new potent CERT inhibitors. One is approved for use in humans and one is approved for use in animals. Evaluation of cellular activity by quantitative mass spectrometry and confocal microscopy showed inhibition of ceramide trafficking and sphingomyelin biosynthesis.
HERBICIDE COMPOSITION COMPRISING CLOMAZONE AND USE THEREOF
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Page/Page column 23, (2018/03/09)
A composition comprising a water-immiscible material or high volatile material encapsulated within a microcapsule is provided, the microcapsules having a shell comprising a polyurea cross-linked by epoxy resin polymer. The method for preparing the same, and the use of the same in the control of unwanted plant growth are also provided.
Epoxy-terminated self-assembled monolayers containing internal urea or amide groups
Ramin, Micha?l A.,Le Bourdon, Gwéna?lle,Heuzé, Karine,Degueil, Marie,Buffeteau, Thierry,Bennetau, Bernard,Vellutini, Luc
supporting information, p. 2783 - 2789 (2015/03/18)
We report the synthesis of new coupling agents with internal amide or urea groups possessing an epoxy-terminal group and trimethoxysilyl-anchoring group. The structural characterizations of the corresponding self-assembled monolayers (SAMs) were performed by polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS). The molecular assembly is mainly based on the intermolecular hydrogen-bonding between adjacent amide or urea groups in the monolayers. Because of the steric hindrance of amide or urea groups, the distance between the alkyl chains is too large to establish van der Waals interactions, inducing their disorder. The reactivity of the epoxy-terminal groups was successfully investigated through reaction with a fluorescent probe. We show that SAMs containing internal urea or amide groups exhibited a higher density of accessible epoxide groups than the corresponding long-chain (C22) glycidyl-terminated SAM.
Novel fluorescent ceramide derivatives for probing ceramidase substrate specificity
Bhabak, Krishna P.,Proksch, Denny,Redmer, Susanne,Arenz, Christoph
supporting information, p. 6154 - 6161 (2012/11/07)
Ceramidases are key regulators of cell fate. The biochemistry of different ceramidases and of their substrate ceramide appears to be complex, mainly due to specific biophysical characteristics at the water-membrane interface. In the present study, we describe the design and synthesis of a set of fluorescently labeled ceramides as substrates for acid and neutral ceramidases. For the first time we have replaced the commonly used polar NBD-dye with the lipophilic Nile Red (NR) dye. Analysis of kinetic data reveal that although both the dyes do not have any noticeable preference for the substitution at acyl or sphingosine (Sph) part in ceramide towards hydrolysis by acid ceramidase, the ceramides with acyl-substituted NBD and Sph-substituted NR dyes have been found to be a better substrate for neutral ceramidase.
