Effect Of Hydroxy Group Research Articles

Effect of hydroxy groups on structural, electronic, and biological properties of methyl carbazate containing hydroxy benzaldehyde-based imines. A combined experimental and theoretical investigation

Interactions present in differently substituted hydroxy based imine derivatives were characterised and identified by the utilisation of spectroscopic techniques in conjunction with X-ray crystallography and theoretical computations. All the target compounds ‘a-c’ crystallises in monoclinic crystal system with P21/c and C2/c space groups. CH…Pi and Pi…Pi interaction are the characteristic interactions present in the target compounds ‘a-c’ The most significant contributions to the crystal packing were found using Hirshfeld surface analysis, and potential contact points were identified. H…H, O…H and C…H contacts and π stacking interactions are the dominant contacts observed in all the crystals these results showed that hydrogen bonding and hydrophobic interactions were significantly present. Furthermore, investigations related to calculations of the molecular electrostatic potential and frontier molecular orbital (highest occupied–lowest unoccupied) were carried out for the optimised structure. The HOMO-LUMO energy gap made it possible to determine the molecule's chemical hardness, chemical inertness, electronegativity, and electrophilicity index, which showed its possible kinetic stability and reactivity. The target compounds' predicted activity spectra (PASS) showed that these compounds exhibit significant Testosterone 17beta-dehydrogenase (NADP+) inhibition activity, with Pa 7.18–7.95. Finally, Testosterone 17beta-dehydrogenase (NADP+) (PDB-ID 3KLP) was used to conduct molecular docking investigations of compounds ‘a-c’. Due to their tiny size and lack of rigidity, which enable them to bind well at any position, a and b exhibit higher binding free energies of -7.08 and -7.00 kcal/mol and inhibition constants of 0.1 and 1.2 µM than compound c.

Effects of Hydroxy Groups in Anthraquinone Dyes on Photocatalytic Activity of Visible-light-sensitized Pt-TiO2 for Hydrogen Evolution

Effects of Hydroxy Groups in Anthraquinone Dyes on Photocatalytic Activity of Visible-light-sensitized Pt-TiO2 for Hydrogen Evolution

Effect of hydroxy groups on nonlinear optical behaviour of encapsulated freebase porphyrin thin films in a borate glass matrix

The development of nonlinear optical (NLO) materials are crucial for technological advancement in the field of optoelectronics and photonics. In this direction, porphyrin molecules are appeared to be a possible building material to play a key role in the light-matter interactions owing to their high degree of delocalized π-electrons. In this report, our primary focus is to understand the effect of hydroxy phenyl derivatives of meso-substituted porphyrins in an encapsulated borate glass matrix through linear and nonlinear optical measurements. The encapsulated porphyrin molecules show strong red shifted Soret (B) and Q-band absorption pattern in the range 455–460 nm and 680–700 nm, respectively, and structure is modified. The Q-band is able to tune by varying the number of hydroxy groups on the phenyl ring of the porphyrin molecule. A similar red shift is observed in the emission spectra of the encapsulated porphyrin along with the appearance of a new emission peak due to impede N-B vibrations in the glass matrix. The NLO behaviour of the encapsulated porphyrin thin films in borate glass matrix show reverse saturable absorption (RSA) at lower intensity region and crossover to saturable absorption (SA) at higher intensity. With the tunable intensity variations across the focal region, these porphyrin thin films exhibit switching behaviour from RSA to SA unclog its potential to act as an optical limiter (in the intensity range less than 10 GW/cm2) and an optical switch (in the high intensity range above ∼ 10 GW/cm2).

Effect of Hydroxy Groups on Nonlinear Optical Behaviour of Freebase Porphyrins Encapsulated in a Borate Glass Matrix

Effect of Hydroxy Groups on Nonlinear Optical Behaviour of Freebase Porphyrins Encapsulated in a Borate Glass Matrix

Effect of hydroxy groups and microtopography generated by a nanosecond-pulsed laser on pure Ti surfaces.

In this paper, we study a process for modifying the surface microtopography of the Ti oxide layer using a nanosecond-pulsed laser (NPL). Even now, the mechanism by which hydroxyl groups are generated on the titanium surface treated by NPL is not clear. Hence, we evaluated the surface properties of the NPL defocus distances on pure titanium surfaces, and investigated the relationship between the generation of hydroxyapatites/cell viability and the titanium surface characteristics. The NPL defocus distance was varied from 0 to 4 mm. Defocus distances of 0 and 2 mm generated microtopographical features on the titanium surface, and the resulting surfaces exhibited a greater density of OH groups than the surface treated with a defocus distance of 4 mm. The surfaces treated using defocus distances of 0 and 2 mm were found to be coated with microspherical hydroxyapatite composed of coexisting plate- and needle-like crystals after immersion in simulated body fluid, and alkaline phosphatase activity assays indicated improved cell compatibility. The improvements in biocompatibility and cell compatibility were due to the pocket-like microtopographical structures formed along the processing trace. These pockets contained a large amount of OH groups, and promoted the growth of hydroxyapatite.

Theoretical study of the substituent effect of hydroxy group on tandem Cope rearrangement and [2 + 2] cycloaddition in cis-1,2-diethynylcyclopropane and its mono-hetero analogues

The tandem Cope rearrangement and [2 + 2] cycloaddition of cis-1,2-diethynyl-1,2-dihydroxycyclopropane and its mono-hetero analogues have been investigated at the B3LYP/6-31+G* level. The presence of the hydroxy group lowers the activation enthalpies for the Cope rearrangement, whereas activation enthalpies for the [2 + 2] cycloaddition are raised as compared to those for their non-hydroxy derivatives. The NBO analysis indicates that in the transition structure involved in the Cope rearrangement, lone pairs of the oxygen atoms of the hydroxy groups are transferred into the σ* C–C bond undergoing migration, as a result of which it is weakened. On the other hand, the lone pairs of the oxygen atoms interact with the π* C=C orbitals of the bis-allenic systems in the intermediate thereby stabilizing it and, thus, suppressing its driving ability for the [2 + 2] cycloaddition. In the products so formed, 6π electrons are delocalized conferring stability on them, which is further augmented by extended conjugation with the hydroxy groups. Due to high stability of these products, activation barrier for the change of enol into ketone is very high.

Spectroscopic and theoretical investigation of the potential anti-tumor and anti-microbial agent, 3-(1-((2-hydroxyphenyl)amino)ethylidene)chroman-2,4-dione.

The coumarin-orthoaminophenol derivative was prepared under mild conditions. Based on crystallographic structure, IR and Raman, 1H and 13C NMR spectra the most applicable theoretical method was determined to be B3LYP-D3BJ. The stability and reactivity parameters were calculated, in the framework of NBO, QTAIM and Fukui functions, form the optimized structure. This reactivity was then probed in biological systems. The antimicrobial activity towards four bacteria and three fungi species was examined and activity was proven. In vitro cytotoxic effects, against human epithelial colorectal carcinoma HCT-116 and human healthy lung MRC-5 cell lines, of the investigated substance are also tested. Compound showed significant cytotoxic effects on HCT-116 cells, while on MRC-5 cells showed no cytotoxic effects. The effect of hydroxy group in ortho-position on the overall reactivity of molecule was examined through molecular docking with Glutathione-S-transferases.

Synthesis of Hydroxysumanene and Substituent Effect of Hydroxy Group on Bowl Inversion Dynamics and Electronic Structure.

Hydroxysumanene was synthesized from acylsumanenes by Baeyer-Villiger oxidation. DFT calculation predicted the higher bowl inversion energy and deeper bowl structure of hydroxysumanene than those of pristine sumanene. The bowl inversion energy of hydroxysumanene was experimentally determined by 2D-EXSY NMR measurement as 21.2 kcal/mol. The energy was larger than that of pristine sumanene (20.3 kcal/mol), which agreed with the calculation result. Electrochemical measurement indicated the higher HOMO level of hydroxysumanene than that of sumanene, which confirmed the electron-rich character of the phenolic function in the bowl skeleton.

Effects of Hydroxy Groups in the A-Ring on the Anti-proteasome Activity of Flavone.

The ubiquitin-proteasome pathway plays an important role in regulating apoptosis and the cell cycle. Recently, proteasome inhibitors have been shown to have antitumor effects and have been used in anticancer therapy for several cancers such as multiple myeloma. Although some flavones, such as apigenin, chrysin and luteolin, have a specific role in the inhibition of proteasome activity and induced apoptosis in some reports, these findings did not address all flavone types. To further investigate the proteasome-inhibitory mechanism of flavonoids, we examined the inhibitory activity of 5,6,7-trihydroxyflavone, baicalein and 5,6,7,4'-tetrahydroxyflavone, scutellarein on extracted proteasomes from mice and cancer cells. Unlike the other flavones, baicalein and scutellarein did not inhibit proteasome activity or accumulate levels of ubiquitinated proteins. These results indicate that flavones with hydroxy groups at positions 5, 6 and 7 of the A-ring lack the anti-proteasome function.

Rheological behaviors of fumed silica/low molecular weight hydroxyl silicone oil

ABSRACTThe structure and viscoelastic properties of fumed silica gels in low molecular weight hydroxyl silicone oil were investigated by means of steady and dynamic rheology. It is found that the fumed silica/hydroxyl silicone oil suspension exhibits shear‐thickening under steady shear and “strain‐thickening” under oscillatory shear condition. Effects of hydroxy groups on the rheological behavior of silicone oil suspension with highly dispersed hydrophilic amorphous silica were investigated by infrared, 1H‐NMR, and rheological test. The results show that the hydroxy groups on this system play an important role on the formation of shear thickening behavior of the suspension solution. At the same particle diameter and mass fraction, the amount of hydroxy groups on this system has a strong effect on increasing the viscosity of the suspension, which is likely due to multiassociation hydrogen bonding between liquid molecules and silanol groups on fumed silica surfaces (SiOH). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40722.

Synthesis and properties of water-soluble 5,8-dihydroxy-1,4-naphthoquinone thioglucosides structurally related to echinochrome

Acetylated hydroxynaphthazarin di- and trithioglucosides structurally related to echinochrome were synthesized. Their deacetylation by the action of sodium methoxide in methanol and the effect of hydroxy groups on this process were studied. Water-soluble echinochrome thioglucosides were synthesized for the first time.

Effect of hydroxy groups on conformational equilibrium in bis-quinolizidine systems

A review of the 99 13C NMR spectra of 72 hydroxy, methoxy or ester derivatives of alkaloids with the sparteine skeleton has been made. An improved method of determination of the conformer fractions in conformational equilibria in bis-quinolizidine compounds of sparteine type has been used to estimate the energy of the hydroxy group effect at various positions. The effect can be explained by intermolecular hydrogen bonds.

Synthetic Benzo[c]phenanthridines with Antileukaemic Activity in Mice

Analogues of the antitumour alkaloids fagaronine and nitidine have been synthesized to investigate their structure-activity relationships against P388 leukaemia in mice. Bulky substituents at the 12-position are well tolerated, whereas substituents larger than methoxy in the 2-position result in total loss of activity. The effects of hydroxy groups in the 2- and 12-positions, which are respectively potency-enhancing and potency destroying, are rationalized in terms of their potential influence on bioavailability. Suitable choice of substituents may allow the production of more potent analogues with improved ability to penetrate lipid membranes.

Catalytic effect of hydroxy groups on reaction of polyamine with tert-butyl acrylate

The reaction of N-cyclohexyl-1,3-propanediamine with tert-butyl acrylate and the catalytic effect of hydroxy groups on the reaction course was investigated by Near Infrared spectroscopy. The reaction was found to be bimolecular and of second order. The dependence of rate constant on catalyst concentration (diols) is linear and the structure of diol used has no effect.

Molecular structure in relation to oestrogenic activity. Compounds without a phenanthrene nucleus

In earlier publications the oestrogenic activity of a number of synthetic substances has been discussed. The first compounds to be tested contained the phenanthrene ring system, and it was shown (Cook, Dodds and Hewett 1933; Cook and Dodds 1933; Cook, Dodds, Hewett and Lawson 1934; Cook, Dodds and Greenwood 1934) that a high degree of activity is possessed by 9 : 10-dihydroxy-9 : 10-di-n-propyl-9 : 10-dihydro-1 : 2 : 5 : 6-dibenzanthracene. Potency was also observed in the highly unsaturated aliphatic acid, clupanodonic acid, whilst a feeble but definite oestrogenic action was found to be possessed by calciferol. Since neither of these compounds contains the phenanthrene ring system, it was considered that this was not essential for oestrogenic properties. A further interesting observation was made in the partial activity of 1-keto-1: 2: 3: 4: 5: 6: 7: 8-octahydroanthracene. This substance produced an advanced pro-oestrus, but full cornification could not be produced no matter how much of the material was administered. A series of derivatives of acenaphthene was studied because these compounds contain a three-ring system arranged in a manner different from that in phenanthrene. These were tested on ovariectomized rats in the manner described in the above-mentioned publications. Table I shows the results obtained with this group of substances. It will be observed that the most potent member of the series is 1 : 2-dihydroxy-1 : 2-di-α-naphthyl acenaphthene. In doses of 10 mg. this compound produces prolonged oestrus. This new substance confirmed our assumption that the phenanthrene ring system was unnecessary for oestrogenic activity and led to experiments with a number of aromatic carbinols (Table II). This series of compounds showed surprising differences in behaviour. Thus, whilst diphenyl-α-naphthyl carbinol possesses full activity in doses of 100 mg. the corresponding diphenyl-β-naphthyl carbinol and triphenyl carbinol were both without action. The effect of hydroxy groups in the aromatic nucleus was then studied and several phenolic diphenyl methane derivatives were investigated with results as shown in Table III. 3 : 3′- and 4 : 4′- dihydroxydiphenyl methane both showed activity, the latter much greater than the former, but the corresponding dicarboxylic acids were without effect. Many potent substances were found in derivatives of 4 : 4′ dihydroxy-diphenyl methane. From this series it appears that the alkyl substituents on the central carbon atom have no influence on the efficacy of the substance. A single phenyl nucleus has a distinct depressing action, and the diphenyl derivative is completely inert. The introduction of methyl groups in the 3 : 3′ positions appears to diminish the potency in some cases.