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The ocular lens is an important determinant of overall vision quality whose refractive and transparent properties change throughout life. The lens operates an internal microcirculation system that generates circulating fluxes of ions, water and nutrients that maintain the transparency and refractive properties of the lens. This flow of water generates a substantial hydrostatic pressure gradient which is regulated by a dual feedback system that uses the mechanosensitive channels TRPV1 and TRPV4 to sense decreases and increases, respectively, in the pressure gradient. This regulation of water flow (pressure) and hence overall lens water content, sets the two key parameters, lens geometry and the gradient of refractive index, which determine the refractive properties of the lens. Here we focus on the roles played by the aquaporin family of water channels in mediating lens water fluxes, with a specific focus on AQP5 as a regulated water channel in the lens. We show that in addition to regulating the activity of ion transporters, which generate local osmotic gradients that drive lens water flow, the TRPV1/4‐mediated dual feedback system also modulates the membrane trafficking of AQP5 in the anterior influx pathway and equatorial efflux zone of the lens. Since both lens pressure and AQP5‐mediated water permeability (PH2O${P_{{{\mathrm{H}}_{\mathrm{2}}}{\mathrm{O}}}}$) can be altered by changes in the tension applied to the lens surface via modulating ciliary muscle contraction we propose extrinsic modulation of lens water flow as a potential mechanism to alter the refractive properties of the lens to ensure light remains focused on the retina throughout life. [ABSTRACT FROM AUTHOR]

In mice, the contraction of the ciliary muscle via the administration of pilocarpine reduces the zonular tension applied to the lens and activates the TRPV1-mediated arm of a dual feedback system that regulates the lens' hydrostatic pressure gradient. In the rat lens, this pilocarpine-induced reduction in zonular tension also causes the water channel AQP5 to be removed from the membranes of fiber cells located in the anterior influx and equatorial efflux zones. Here, we determined whether this pilocarpine-induced membrane trafficking of AQP5 is also regulated by the activation of TRPV1. Using microelectrode-based methods to measure surface pressure, we found that pilocarpine also increased pressure in the rat lenses via the activation of TRPV1, while pilocarpine-induced removal of AQP5 from the membrane observed using immunolabelling was abolished by pre-incubation of the lenses with a TRPV1 inhibitor. In contrast, mimicking the actions of pilocarpine by blocking TRPV4 and then activating TRPV1 resulted in sustained increase in pressure and the removal of AQP5 from the anterior influx and equatorial efflux zones. These results show that the removal of AQP5 in response to a decrease in zonular tension is mediated by TRPV1 and suggest that regional changes to PH2O contribute to lens hydrostatic pressure gradient regulation. [ABSTRACT FROM AUTHOR]

The optical properties of the bovine lens have been shown to be actively maintained by an internal microcirculation system. In the mouse lens, this water transport through gap junction channels generates an intracellular hydrostatic pressure gradient, which is subjected to a dual feedback regulation that is mediated by the reciprocal modulation of the transient receptor potential vanilloid channels TRPV1 and TRPV4. Here we test whether a similar feedback regulation of pressure exists in the bovine lens and whether it regulates overall lens optics. Lens pressure was measured using a microelectrode/pico-injector-based pressure measurement system, and lens optics were monitored in organ cultured lenses using a laser ray tracing system. Like the mouse, the bovine lenses exhibited a similar pressure gradient (0 to 340 mmHg). Activation of TRPV1 with capsaicin caused a biphasic increase in surface pressure, while activation of TRPV4 with GSK1016790A caused a biphasic decrease in pressure. These biphasic responses were abolished if lenses were preincubated with either the TRPV1 inhibitor A-889425 or the TRPV4 inhibitor HC-067047. While modulation of lens pressure by TRPV1 and TRPV4 had minimal effects on lens power and overall vision quality, the changes in lens pressure did induce opposing changes to lens geometry and its gradient of refractive index that effectively kept lens power constant. Hence, our results suggest that the TRPV1/4-mediated feedback control of lens hydrostatic pressure operates to ensure that any fluctuations in lens water transport, and consequently water content, do not result in changes in lens power and therefore overall vision quality. [ABSTRACT FROM AUTHOR]

Transport of water is critical for maintaining the transparency of the avascular lens, and the lens is known to express at least five distinctly different water channels from the Aquaporin (AQP) family of proteins. In this study we report on the identification of a sixth lens AQP, AQP3 an aquaglyceroporin, which in addition to water also transports glycerol and H 2 O 2. AQP3 was identified at the transcript level and protein levels using RT-PCR and Western blotting, respectively, in the mouse, rat, bovine and human lens, showing that its expression is conserved in the mammalian lens. Western blotting showed AQP3 in the lens exists as 25 kDa non-glycosylated and 37 kDa glycosylated monomeric forms in all lens species. To identify the regions in the lens where AQP3 is expressed Western blotting was repeated using epithelial, outer cortical and inner cortical/core fractions isolated from the mouse lens. AQP3 was found in all lens regions, with the highest signal of non-glycosylated AQP3 being found in the epithelium. While in the inner cortex/core region AQP3 signal was not only lower but was predominately from the glycosylated form of AQP3. Immunolabelling of lens sections with AQP3 antibodies confirmed that AQP3 is found in all regions of the adult mouse, and also revealed that the subcellular distribution of AQP3 changes as a function of fiber cell differentiation. In epithelial and peripheral fiber cells of the outer cortex AQP3 labelling was predominately associated with membrane vesicles in the cytoplasm, but in the deeper regions of the lens AQP3 labelling was associated with the plasma membranes of fiber cells located in the inner cortex and core of the lens. To determine how this adult pattern of AQP3 subcellular distribution was established, immunolabelling for AQP3 was performed on embryonic and postnatal lenses. AQP3 expression was first detected on embryonic day (E) 11 in the membranes of primary fiber cells that have started to elongate and fill the lumen of the lens vesicle, while later at E16 the AQP3 labelling in the primary fiber cells had shifted to a predominately cytoplasmic location. In the following postnatal (P) stages of lens growth at P3 and P6, AQP3 labelling remained cytoplasmic across all regions of the lens and it was not until P15 when the pattern of localisation of AQP3 changed to an adult distribution with cytoplasmic labelling detected in the outer cortex and membrane localisation detected in the inner cortex and core of the lens. Comparison of the AQP3 labelling pattern to those obtained previously for AQP0 and AQP5 showed that the subcellular distribution was more similar to AQP5 than AQP0, but there were still significant differences that suggest AQP3 may have unique roles in the maintenance of lens transparency. • Aquaporin (AQP) 3 was identified as a sixth lens AQP at the transcript and protein levels in the mammalian lens. • AQP3 protein expression changes as a function of fiber cells differentiation and lens embryonic and postnatal growth. • AQP3 expression is more like AQP5 than AQP0 but spatial differences between AQP3 and AQP5 suggest they have unique functions. [ABSTRACT FROM AUTHOR]

Although the functionality of the lens water channels aquaporin 1 (AQP1; epithelium) and AQP0 (fiber cells) is well established, less is known about the role of AQP5 in the lens. Since in other tissues AQP5 functions as a regulated water channel with a water permeability (PH2O) some 20 times higher than AQP0, AQP5 could function to modulate PH2O in lens fiber cells. To test this possibility, a fluorescence dye dilution assay was used to calculate the relative PH2O of epithelial cells and fiber membrane vesicles isolated from either the mouse or rat lens, in the absence and presence of HgCl2, an inhibitor of AQP1 and AQP5. Immunolabeling of lens sections and fiber membrane vesicles from mouse and rat lenses revealed differences in the subcellular distributions of AQP5 in the outer cortex between species, with AQP5 being predominantly membranous in the mouse but predominantly cytoplasmic in the rat. In contrast, AQP0 labeling was always membranous in both species. This species-specific heterogeneity in AQP5 membrane localization was mirrored in measurements of PH2O, with only fiber membrane vesicles isolated from the mouse lens, exhibiting a significant Hg2+-sensitive contribution to PH2O. When rat lenses were first organ cultured, immunolabeling revealed an insertion of AQP5 into cortical fiber cells, and a significant increase in Hg2+-sensitive PH2O was detected in membrane vesicles. Our results show that AQP5 forms functional water channels in the rodent lens, and they suggest that dynamic membrane insertion of AQP5 may regulate water fluxes in the lens by modulating PH2O in the outer cortex. [ABSTRACT FROM AUTHOR]

Aquaporins (AQPs), by playing essential roles in the maintenance of ocular lens homeostasis, contribute to the establishment and maintenance of the overall optical properties of the lens over many decades of life. Three aquaporins, AQP0, AQP1 and AQP5, each with distinctly different functional properties, are abundantly and differentially expressed in the different regions of the ocular lens. Furthermore, the diversity of AQP functionality is increased in the absence of protein turnover by age-related modifications to lens AQPs that are proposed to alter AQP function in the different regions of the lens. These regional differences in AQP functionality are proposed to contribute to the generation and directionality of the lens internal microcirculation; a system of circulating ionic and fluid fluxes that delivers nutrients to and removes wastes from the lens faster than could be achieved by passive diffusion alone. In this review, we present how regional differences in lens AQP isoforms potentially contribute to this microcirculation system by highlighting current areas of investigation and emphasizing areas where future work is required. [ABSTRACT FROM AUTHOR]

Lens water transport generates a hydrostatic pressure gradient that is regulated by a dual-feedback system that utilizes the mechanosensitive transient receptor potential vanilloid (TRPV) channels, TRPV1 and TRPV4, to sense changes in mechanical tension and extracellular osmolarity. Here, we investigate whether the modulation of TRPV1 or TRPV4 activity dynamically affects their membrane trafficking. Mouse lenses were incubated in either pilocarpine or tropicamide to alter zonular tension, exposed to osmotic stress, or the TRPV1 and TRPV4 activators capsaicin andGSK1016790A (GSK101), and the effect on the TRPV1 and TRPV4 membrane trafficking in peripheral fiber cells visualized using confocal microscopy. Decreases in zonular tension caused the removal of TRPV4 from the membrane of peripheral fiber cells. Hypotonic challenge had no effect on TRPV1, but increased the membrane localization of TRPV4. Hypertonic challenge caused the insertion of TRPV1 and the removal of TRPV4 from the membranes of peripheral fiber cells. Capsaicin caused an increase in TRPV4 membrane localization, but had no effect on TRPV1; while GSK101 decreased the membrane localization of TRPV4 and increased the membrane localization of TRPV1. These reciprocal changes in TRPV1/4 membrane localization are consistent with the channels acting as mechanosensitive transducers of a dual-feedback pathway that regulates lens water transport. [ABSTRACT FROM AUTHOR]

The molecule of the title compound, C9H7NO, is nearly planar, with an r.m.s. deviation of 0.018 (7) Å. In the crystal structure, two molecules form an R²2(8) centrosymmetric dimer through N H⋯O hydrogen bonds. The three-dimensional packing is additionally stabilized through weak C—H⋯O interactions. [ABSTRACT FROM AUTHOR]

The reaction of K2PtCl4 with 3-amino-5-methyl-5-phenylhydantoin (amphh, L) and KI in aqueous ethanol yields dark violet crystals of a binuclear platinum(II) complex. The molecular structure of the complex was determined by single-crystal X-ray diffraction methods. The complex crystallizes in the triclinic space group [image omitted] with a = 8.458(3), b = 11.016(2), c = 16.249(3) (Å), α = 94.630(14), β = 100.63(2), γ = 108.55(4)° and Z = 2. The structure consists of [K2L4]2+ cations and [Pt2I6]2- anions bridged by K-I bonds to form quasi-one-dimensional chains along the b axis. Chains are linked by K+ ··· π(Ph) interactions and N-H ··· O hydrogen bonds. The complex is compared with data for related structures. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound [systematic name: 3-amino-1,3-diazaspiro[4.5]decane-2,4-dione-phenylboronic acid (1/1)], C8H13N3O2·C6H7BO2, molecules are held together by O—H…O, N—H…O and C—H…O hydrogen bonds and by an N—H…π interaction. [ABSTRACT FROM AUTHOR]

The title compound, C26H26N2O3, crystallizes as a racemic mixture of R, R and S, S enantiomers. The two independent mol­ecules show a similar conformation. They are connected via C—H⋯O and C—H⋯π inter­actions to form ribbons along the a axis. [ABSTRACT FROM AUTHOR]

The molecule of the title compound, C5H14NO4P, exists as a zwitterion rather than as [1-(hydroxyethyl­amino)propyl]­phospho­nic acid, with the N atom of the amino group protonated and the phospho­nic acid group negatively charged. In the crystal structure, the molecules are linked via extensive hydrogen bonding, forming layers parallel to (100). [ABSTRACT FROM AUTHOR]

The lens is an important determinant of overall vision quality whose refractive and transparent properties change throughout life. Alterations to the refractive properties of the lens contribute to the process of emmetropisation in early childhood, and then the gradual loss in lens power that occurs throughout adulthood. In parallel to these changes to lens refractive power, age-dependent increases in lens stiffness and light scattering result in presbyopia and cataract, respectively. In recent years it has been confirmed that the lens operates an internal microcirculation system that generates circulating fluxes of ions, water and nutrients that maintain the refractive properties and transparency of the lens. By actively regulating lens water content, the microcirculation system controls two key parameters, lens geometry and the gradient of refractive index, which together determine the refractive properties of the lens. Furthermore, by delivering nutrients and antioxidants to the lens nucleus, the microcirculation system maintains lens transparency by preventing crystallin aggregation. Interestingly, the solubility, intramolecular packing and refractive index increment of crystallin proteins can be modulated by the ability of crystallin proteins to dynamically bind water, a processed called syneresis. In a series of previous studies it has been shown that the application of external pressure to the lens can induce syneresis. Since it is now known that lens water transport generates a substantial internal hydrostatic pressure gradient, we speculate that the microcirculation is capable of regulating crystallin function by altering the amount of water bound to lens proteins in the nucleus, where the pressure gradient and protein concentrations are the highest. Here we present evidence for the links between lens transport, pressure, syneresis and protein function. Furthermore, because the lens pressure gradient can be regulated by intrinsic and extrinsic stimuli, we suggest mechanisms via which this integrative system can be used to effect the changes to the refractive and transparent properties of the lens that are observed across our lifetime. [ABSTRACT FROM AUTHOR]

The crystal structures of four cyclo­alkane­spiro-4′-imidazolidine-2′,5′-dithiones, namely cyclo­pentane­spiro-4′-imidazolidine-2′,5′-dithione {systematic name: 1,3-diaza­spiro­[4.4]­nonane-2,4-dithione}, C7H10N2S2, cyclo­hexane­spiro-4′-imidazolidine-2′,5′-dithione {systematic name: 1,3-diaza­spiro­[4.5]decane-2,4-dithione}, C8H12N2S2, cyclo­heptane­spiro-4′-imidazolidine-2′,5′-dithione {systematic name: 1,3-diaza­spiro­[4.6]undecane-2,4-dithione}, C9H14N2S2, and cyclo­octane­spiro-4′-imidazolidine-2′,5′-dithione {systematic name: 1,3-di­aza­spiro­[4.7]dodecane-2,4-dithione}, C10H16N2S2, have been determined. The three-dimensional packing in all of the structures is based on closely similar chains, in which hydantoin moieties are linked through N—H⋯S hydrogen bonding. The size of the cyclo­alkane moiety influences the degree of its deformation. In the cyclo­octane compound, the cyclo­octane ring assumes both boat–chair and boat–boat conformations. [ABSTRACT FROM AUTHOR]

The title compound [systematic name: 1′-amino­cyclo­hexane­spiro-4′-imidazole-2′,5′(3′ H,4′ H)-dione], C8H13N3O2, has been synthesized and was found to crystallize in two different structures, both monoclinic and both with the same P21/ c space group. In the first structure, there are two mol­ecules in the asymmetric unit, one of which uses all of its hydrogen-bond donors and acceptors and forms undulating layers, while the other forms chains propagating perpendicular to the layers. In the second structure, there is only one independent mol­ecule and the packing is based on a chain structure mediated by hydrogen bonding between the hydantoin moieties and further grouped into hydro­philic layers separated by layers of the hydro­phobic cyclo­hex­yl groups. [ABSTRACT FROM AUTHOR]

Abstract: Until recently, the lens was thought to express only two aquaporin (AQP) water channels, AQP1 and AQP0. In this study we confirm lenticular AQP5 protein expression by Western blotting and mass spectrometry in lenses from a variety of species. In addition, confocal microscopy was used to map cellular distributions of AQP5 in mouse, rat and human lenses. Tandem mass spectrometry of a human lens membrane preparation revealed extensive sequence coverage (56.2%) of AQP5. Western blotting performed on total fiber cell membranes from mouse, rat, bovine and human lenses confirmed AQP5 protein expression is conserved amongst species. Western blotting of dissected lens fractions suggests that AQP5 is processed in the lens core by C-terminal truncation. Immunohistochemistry showed that AQP5 signal was most abundant in the lens outer cortex and decreased in intensity in the lens core. Furthermore, AQP5 undergoes differentiation-dependent changes in subcellular location from an intracellular localization in differentiating fiber cells to the plasma membrane of mature fiber cells upon the loss of fiber cell nuclei. Our results show that AQP5 is a significant component of lens fiber cell membranes, representing the second most abundant water channel in these cells. Together, the changes to AQP5 distribution and structure are likely to modulate the functional role of AQP5 in different regions of the lens. [Copyright &y& Elsevier]

Presbyopia is caused by age-related lenticular hardening, resulting in near vision loss, and it occurs in almost every individual aged ≥50 years. The lens experiences mechanical pressure during for focal adjustment to change its thickness. As lenticular stiffening results in incomplete thickness changes, near vision is reduced, which is known as presbyopia. Piezo1 is a mechanosensitive channel that constantly senses pressure changes during the regulation of visual acuity, and changes in Piezo1 channel activity may contribute to presbyopia. However, no studies have reported on Piezo1 activation or the onset of presbyopia. To elucidate the relevance of Piezo1 activation and cross-linking in the development of presbyopia, we analysed the function of Piezo1 in the lens. The addition of Yoda1, a Piezo1 activator, induced an increase in transglutaminase 2 (TGM2) mRNA expression and activity through the extra-cellular signal-regulated kinase (ERK) 1/2 and c-Jun-NH2-terminal kinase1/2 pathways. In ex vivo lenses, Yoda1 treatment induced γ-crystallin cross-linking via TMG2 activation. Furthermore, Yoda1 eye-drops in mice led to lenticular hardening via TGM2 induction and activation in vivo , suggesting that Yoda1-treated animals could serve as a model for presbyopia. Our findings indicate that this presbyopia-animal model could be useful for screening drugs for lens-stiffening inhibition. [Display omitted] • Ca2+ influx after Piezo1 activation is required for TGM2 activity. • Both MEK/ERK and MKK/JNK pathway activation were necessary for TGM2 activity. • Yoda1 ophthalmic treated animals could be the first presbyopia animal model. • Presbyopia-animal model is useful for screening drugs for lens-stiffening inhibition. [ABSTRACT FROM AUTHOR]

The transient receptor protein vanilloid channels, TRPV1 and TRPV4, have recently been shown to be mechanosensors in the ocular lens that act to transduce physical changes in lens volume and internal hydrostatic pressure into the activation of signalling pathways in lens epithelial cells. These pathways in turn regulate ion and water transport to ensure that the optical properties of the lens remain constant. Despite the functional evidence that implicate the roles of TRPV1 and TRPV4 in the lens, their respective cellular expression patterns in the different regions of the lens has to date not been fully characterised. Using Western blotting we have confirmed that TRPV1 and TRPV4 are expressed throughout all regions (epithelium, outer cortex, inner cortex/core) of the adult mouse lens. Subsequent immunolabeling of lens cryosections confirmed that TRPV1 and TRPV4 are expressed throughout all regions of the lens, but revealed differentiation-dependent differences in the subcellular expression of the two channels in the different regions. In the epithelium and outer cortex, intense TRPV1 and TRPV4 labeling was predominately associated with the cytoplasm. In a discrete zone in the inner cortex, labeling for both proteins was greatly diminished, but could be enhanced by incubating sections with the detergent Triton X-100 to reveal TRPV1 and TRPV4 labelling that was associated with the membrane. This suggests that in this region of the lens there is a potential interacting protein that masks the binding of the TRPV1 and TRPV4 antibodies to their respective epitopes in the lens inner cortex. In the core of the lens, which contains the embryonic nucleus, TRPV1 and TRPV4 labelling was associated exclusively with fibre cell membranes. This labelling in the lens core of the adult mouse lens appeared to originate in early development as a similar membrane labelling was observed at embryonic day 10 (E10) of the cells in the lens vesicle that subsequently forms the embryonic nucleus in the adult lens. During subsequent stages of embryonic development TRPV1 and TRPV4 remained membranous in the inner cortex and core, while showing labelling that was associated with the cytoplasm in the superficial outer cortical region. The extent of cytoplasmic labelling for TRPV4, but not TRPV1, in this cortical region could however be dynamically regulated by cutting the zonules that normally attach the lens to the ciliary body. We have shown an early onset and continuous expression of TRPV1 and TRPV4 across all lens regions, and that TRPV4 can be dynamically trafficked into the membranes of differentiating fibre cells, results that suggests that these mechanosensitive channels may also be functionally active in lens fibre cells. • The mechanosensitive channels TRPV1 and TRPV4 are expressed in all lens regions. • The subcellular distribution of TRPV1/4 changes as fiber cells differentiate. • TRPV4 was dynamically recruited to the membrane by changes in zonular tension. • TRPV1/4 regulate the hydrostatic pressure and may mediate fiber cell Na+ conductance. [ABSTRACT FROM AUTHOR]

The title compound, C6H12NO5P, was synthesized as an inter­mediate phase in a search for new N-(phosphono­methyl)glycine derivatives. The mol­ecules are held together by O—H⋯O hydrogen bonds, forming chains along the b axis in the crystal structure. The observed mol­ecular structure is compared with that calculated by the density functional theory method. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, C9H12N+·C4H4O−, contains two independent 1,2,3,4-tetrahydroisoquinolinium cations and two independent hydrogensquarate anions. In one of the cations, the N atom is disordered over two positions with occupancies of approximately 0.8 and 0.2. The pyridinium rings adopt envelope conformations. The hydrogensquarate anions are linked to form cyclic tetramers through strong O—H...O hydrogen bonds. The tetrahydroisoquinolinium and hydrogensquarate ions are linked via N—H...O hydrogen bonds, forming a three-dimensional framework. [ABSTRACT FROM AUTHOR]

In the title compound, C11H10N+·C4H5O6−·2H2O, hydrogen tartrate anions and water molecules are linked by strong O—H...O hydrogen bonds to form corrugated layers. The 4-phenylpyridinium cation decorates the layer from both sides, being hydrogen bonded to the water molecule only. The three-dimensional packing of the complex layers is accomplished by strong π–π interactions of 3.668 (2) Å between the centroids of the benzyl and pyridine rings related by the symmetry operator ( x −  , − y +  , − z). [ABSTRACT FROM AUTHOR]

The serum amyloid A protein is one of the major reactants in the acute-phase response. Using representational difference analysis comparing RNA from normal and involuting quarters of a dairy cow mammary gland, we found an mRNA encoding the SAA3 protein (M-SAA3). The M-SAA3 mRNA was localized to restricted populations of bovine mammary epithelial cells (MECs). It was expressed at a moderate level in late pregnancy, at a low level through lactation, was induced early in milk stasis, and expressed at high levels in most MECs during mid to late involution and inflammation/mastitis. The mature M-SAA3 peptide was expressed in Escherichia coli, antibodies made, and shown to have antibacterial activity against E. coli, Streptococcus uberis and Pseudomonas aeruginosa. These results suggest that the mammary SAA3 may have a role in protection of the mammary gland during remodelling and infection and possibly in the neonate gastrointestinal tract. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of several new phosphorus-containing partially lower rim substituted derivatives of 5,11,17,23-tetra(t-butyl) calix(4)arene (I) and 5,11,17,23-tetra(t-octyl)calix(4)arene (II), namely 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(diphenylphosphinoyl-oxy) calix(4)arene (IV); 5,11,17,23-tetra(t-butyl)-25-hydroxy-26,27,28-tris(tetramethyldiamido-phosphinoyl-oxy) calix(4)arene (Vb); 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene (VI); 5,11,17,23-tetra (t-octyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene (VII) are reported. The structure of the synthesized calix(4)arene derivatives are identified and confirmed by elemental analysis, IR, 1H, 13C, 31P{1H} NMR spectroscopy and mass spectrometry as and X-ray crystallographic analysis of 5,11,17,23-tetra(t-butyl)-25,27-dihydroxy-26,28-bis(dimethyl-phosphinoyl-methoxy) calix(4)arene VI. According to the NMR spectra, all calix(4)arenes are in cone conformation. [ABSTRACT FROM AUTHOR]

Abstract: A new modified calix[4]arene, namely 5,11,17,23-tetra-tert-butyl-25,27-dihydroxy-26,28-bis[(tetramethyldiamidophosphinyl)oxy]calix[4]arene (L) has been prepared by reacting the parent calixarene with tetramethyldiamidophosphoric acid chloride, and its structure was solved by the X-ray diffraction method in the solid state and characterized in solution using 1H, 13C, 31P NMR and mass spectral (ES-MS and FAB-MS) data. The coordination ability of L towards Na+ showed the formation of two different complex species, [NaL]+[AuCl4]− ·4H2O (1) and [Na2L2](ClO4)2 ·(CH3OH)4 (2), depending on the reaction conditions and nature of the counter ion. Complex 1 is structurally characterized using NMR (1H, 13C, 31P) and mass spectral data. Complex 2 crystallizes with four molecules of methanol, two of them being bridges between two calixarene units and its structure was determined by X-ray analysis. [Copyright &y& Elsevier]

The article presents information on the structure of codeinone. Codeinone has been found to possess antitumor potential, with high cytotoxic activity against human promyelocytic leukaemic cell lines and is known that codeinone in the living cell is produced from the reaction of codeine with nicotinamide adenine dinucleotide phosphate. The molecular structure exhibits features typical for morphine derivatives, with a T-shaped configuration. The crystal packing was found to be stabilized by weak intermolecular C-H&3x22EF;O interactions.

The title compound (systematic name: 6α-acet­oxy-4,5α-ep­oxy-3-meth­oxy-17-meth­yl-morphin-7-ene), C20H23NO4, crystallizes with one mol­ecule in the asymmetric unit. The mol­ecular structure exhibits features typical of morphine derivatives with a T configuration. The three-dimensional packing is stabilized by inter­molecular C—H⋯N and C—H⋯π inter­actions. [ABSTRACT FROM AUTHOR]

The title compound, C16H9NO4, also known as the 3-benzoylpyridinium betaine of squaric acid, exhibits a dipolar electronic ground-state structure with a positively charged pyridinium fragment and a negatively charged squarate moiety. In the molecule, the two aromatic rings are twisted by 56.03 (2)° relative to one another. The three-dimensional packing of the molecules is stabilized by C—H··O· short contacts. [ABSTRACT FROM AUTHOR]

The mol­ecule of the title compound, C21H22N2O2, is nearly planar, except for the C(CH3)2 group on the cyclo­hexene ring. Molecules are connected via electrostatic C⋯O contacts, forming zigzag pseudo-chains along the c axis. [ABSTRACT FROM AUTHOR]

In the title compound, 3,4-dioxo-2-(pyridinium-1-yl)cyclobut-1-enolate, C9H5NO3, molecules are connected three-dimensionally through nonclassical C—H...O and π–π interactions [3.220 (3) Å] between the oppositely charged squarate and pyridinium fragments. Classical hydrogen-bonding interactions are not observed. In the unit cell, only half an independent molecule is present and a twofold rotation axis passes through the pyridinium ring and the opposite CO group. [ABSTRACT FROM AUTHOR]

In the title compound, sodium 2-hydr­oxy-3,4-dioxocyclo­but-1-en-1-olate monohydrate, Na+·C4HO4−·H2O, the Na atom is six-coordinated by the O atoms from four hydrogensquarate anions and two water mol­ecules. The three-dimensional packing is stabilized by a system of hydrogen bonds. [ABSTRACT FROM AUTHOR]