Aluminum and gallium compounds of 3-hydroxy-4-pyridinones: synthesis, characterization, and crystallography of biologically active complexes with unusual hydrogen bonding

1988 ◽  
Vol 27 (6) ◽  
pp. 1045-1051 ◽  
Author(s):  
William O. Nelson ◽  
Timothy B. Karpishin ◽  
Steven J. Rettig ◽  
Chris Orvig
2017 ◽  
Vol 25 (3) ◽  
pp. 94-104
Author(s):  
Maryam A Jordaan ◽  
Michael Shapi

This study sought to investigate the solvent-dependency on the photolysis of efavirenz to gain insight into the photoprocesses involved. The primary mechanisms were firstly the excited-state intramolecular proton transfer (i.e. phototautomerization), which generated the imidic acid phototautomer observed as [M-H]− quasimolecular ion at m/z 314.0070 in the high-performance liquid chromatography–electrospray ionization–time-of-flight mass spectrometry in the negative mode. Secondly, the photoinduced α-cleavage with the loss of a carbonyl group occurred (i.e. photodecarbonylation) to form the photoproduct at m/z 286.0395. The ultraviolet–visible spectra illustrated a large, hyperchromic, and slight bathochromic effect in both the π→π* and n→π* electronic transitions. The largest bathochromic effect was prevalent in the chloroform solvent, i.e. chloroform (π* = 0.58; β = 0.00; α = 0.44) > methanol (π* = 0.60; β = 0.66; α = 0.98) > acetonitrile (π* = 0.75; β = 0.40; α = 0.19). This is due to the significant interaction of the amino group with the excited carbonyl moiety which is attributed to intramolecular phototautomerization resulting in a larger energy shift of the electronic state. A plausible explanation is due to the hydrogen bond donor ability of the polar methanol and nonpolar chloroform solvents, which stabilized the polarized imidic acid phototautomer by means of hydrogen bonding interactions, as opposed to the aprotic acetonitrile which exhibits no hydrogen bonding interactions. The study would form the basis for further photolytic analyses and syntheses to generate a plethora of novel photoproducts with anti-HIV activity based on the biologically active benzoxazinone framework of efavirenz.


2017 ◽  
Vol 73 (9) ◽  
pp. 1368-1371 ◽  
Author(s):  
Ahmed M. Zheoat ◽  
Alexander I. Gray ◽  
John O. Igoli ◽  
Alan R. Kennedy ◽  
Valerie A. Ferro

The biologically active title compounds have been isolated fromHibiscus sabdariffaplants, hibiscus acid as a dimethyl sulfoxide monosolvate [systematic name: (2S,3R)-3-hydroxy-5-oxo-2,3,4,5-tetrahydrofuran-2,3-dicarboxylic acid dimethyl sulfoxide monosolvate], C6H6O7·C2H6OS, (I), and hibiscus acid dimethyl ester [systematic name: dimethyl (2S,3R)-3-hydroxy-5-oxo-2,3,4,5-tetrahydrofuran-2,3-dicarboxylate], C8H10O7, (II). Compound (I) forms a layered structure with alternating layers of lactone and solvent molecules, that include a two-dimensional hydrogen-bonding construct. Compound (II) has two crystallographically independent and conformationally similar molecules per asymmetric unit and forms a one-dimensional hydrogen-bonding construct. The known absolute configuration for both compounds has been confirmed.


Author(s):  
Catherine S. Branch ◽  
Janusz Lewinski ◽  
Iwona Justyniak ◽  
Simon G. Bott ◽  
Janusz Lipkowski ◽  
...  

2009 ◽  
Vol 63 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Nemanja Trisovic ◽  
Gordana Uscumlic ◽  
Slobodan Petrovic

Hydantoin is a five-membered cyclic ureide that is present in numerous biologically active compounds including antiarrhytmics, anticonvulsants and antitumor agents. This paper describes different ways of synthesis of hydantoin-derivatives, their physical properties and reactivity. Also, the most widely used hydantoin anticonvulsants and the analysis of structureactivity relationships of anticonvulsant drugs in terms of lipophilicity and hydrogen bonding are presented here.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Reza Taheri-Ledari ◽  
Wenjie Zhang ◽  
Maral Radmanesh ◽  
Nicole Cathcart ◽  
Ali Maleki ◽  
...  

Abstract Background Applied nanomaterials in targeted drug delivery have received increased attention due to tangible advantages, including enhanced cell adhesion and internalization, controlled targeted release, convenient detection in the body, enhanced biodegradation, etc. Furthermore, conjugation of the biologically active ingredients with the drug-containing nanocarriers (nanobioconjugates) has realized impressive opportunities in targeted therapy. Among diverse nanostructures, halloysite nanotubes (NHTs) with a rolled multilayer structure offer great possibilities for drug encapsulation and controlled release. The presence of a strong hydrogen bond network between the rolled HNT layers enables the controlled release of the encapsulated drug molecules through the modulation of hydrogen bonding either in acidic conditions or at higher temperatures. The latter can be conveniently achieved through the photothermal effect via the incorporation of plasmonic nanoparticles. Results The developed nanotherapeutic integrated natural halloysite nanotubes (HNTs) as a carrier; gold nanoparticles (AuNPs) for selective release; docetaxel (DTX) as a cytotoxic anticancer agent; human IgG1 sortilin 2D8-E3 monoclonal antibody (SORT) for selective targeting; and 3-chloropropyltrimethoxysilane as a linker for antibody attachment that also enhances the hydrophobicity of DTX@HNT/Au-SORT and minimizes DTX leaching in body’s internal environment. HNTs efficiently store DTX at room temperature and release it at higher temperatures via disruption of interlayer hydrogen bonding. The role of the physical expansion and disruption of the interlayer hydrogen bonding in HNTs for the controlled DTX release has been studied by dynamic light scattering (DLS), electron microscopy (EM), and differential scanning calorimetry (DSC) at different pH conditions. HNT interlayer bond disruption has been confirmed to take place at a much lower temperature (44 °C) at low pH vs. 88 °C, at neutral pH thus enabling the effective drug release by DTX@HNT/Au-SORT through plasmonic photothermal therapy (PPTT) by light interaction with localized plasmon resonance (LSPR) of AuNPs incorporated into the HNT pores. Conclusions Selective ovarian tumor targeting was accomplished, demonstrating practical efficiency of the designed nanocomposite therapeutic, DTX@HNT/Au-SORT. The antitumor activity of DTX@HNT/Au-SORT (apoptosis of 90 ± 0.3%) was confirmed by in vitro experiments using a caov-4 (ATCC HTB76) cell line (sortilin expression > 70%) that was successfully targeted by the sortilin 2D8-E3 mAb, tagged on the DTX@HNT/Au. Graphic abstract


2007 ◽  
Vol 63 (11) ◽  
pp. o4215-o4216 ◽  
Author(s):  
Muhammad Zia-ur-Rehman ◽  
Jamil Anwar Choudary ◽  
Mark R. J. Elsegood ◽  
Hamid Latif Siddiqui ◽  
George W. Weaver

The title compound, C16H13N3O5S·C2H6OS, is of interest as a precursor to biologically active (benzothiazin-3-yl)quinazolinones and its structure is reported here as the dimethyl sulfoxide (DMSO) solvate. The structure displays intramolecular N—H...O and O—H...O hydrogen bonding, giving rise to six-membered hydrogen-bonded rings, with head-to-tail intermolecular pairs of N—H...O hydrogen bonds linking pairs of neighbouring molecules and two independent N—H...O=S intermolecular hydrogen bonds to the DMSO molecule resulting in the pairs of molecules being linked into stepped chains parallel to a.


Author(s):  
Tatyana V. Kustova ◽  
Elena A. Rogova ◽  
Alexander M. Sinitsyn

Synthetic methods of organic chemistry which are currently available in scientific literature allow obtaining a large number macroheterocycles with structurally different internal coordination cavities. They also provide a number of convenient ways to attach to a macrocyclic platform various biologically active heterocyclic fragments such as guanazol. This paper discusses the synthesis and composition of gallium complexes of cyclic and acyclic compounds based on 3,5-diamino-1H-1,2,4-triazol (guanazol), which is itself widely used in medical practice and, most importantly, for the treatment of cancer, in particular, breast cancer ("Anastrozole", "Letrozole"). Interest in gallium compounds is associated with the discovery of a high tropicity of this element to the DNA of tumor cells, as well as cells of the reticuloendothelial system (macrophages and lymphocytes). Therefore, the synthesis of new potential drugs with gallium salts for tumor chemotherapy is an urgent task. The gallium complex of a macroheterocyclic compound of symmetrical structure based on guanazole was obtained through the formation of a three-unit product - 3,5-bis - (5 (6)-tert-butyl-3-iminoisoindoline-1-ilidenamino)-1,2,4-triazole and its complex, followed by cyclization of 3,5-diamino-1H-1,2,4-triazole in phenol. The structure of the obtained compounds was proved using modern physicochemical research methods (UV, IR, NMR spectroscopy, mass spectrometry, and elemental analysis). In the mass spectra of the obtained compounds there are peaks of molecular ions of the target products and their fragmentation products. The coincidence of the m/z values with the mass of molecular ions, as well as the characteristic distributions of molecular ions with the calculated values, confirms the composition of the synthesized gallium complexes.


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