scholarly journals Polymorphism in Griseofulvin: New Story of an Old Drug with Polyethylene Glycol

2021 ◽  
Author(s):  
Xiao Ou ◽  
Shuting Li ◽  
Yunyun Chen ◽  
Haowei Rong ◽  
Ao Li ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Solid Dispersions ◽  
Melt Crystallization ◽  
X Ray ◽  
X Ray Crystallography ◽  
Polymer Addition ◽  
Single Crystal Structures ◽  
Solid Form ◽  
First Time ◽  
And Storage

Griseofulvin (GSF) is an antifungal drug that has been clinically used for six decades. Here, we present a rich polymorphism of GSF crystallizing from GSF dispersions with polyethylene glycol (PEG), including five true polymorphs (Forms I-V) and one inclusion complex (IC). Two new polymorphs were reported for the first time, denoted Forms IV and V. Single-crystal structures of new polymorphs and a GSF-PEG IC were determined by X-ray crystallography using single crystals cultivated by microdroplet melt crystallization. A comprehensive solid form landscape of GSF is established to describe phase conversions between polymorphs. Enhancement in molecular mobility by PEG is suggested to be the reason for the nucleation of two new polymorphs, while the small geographic radius of PEG is attributed to the formation of a GSF-PEG IC increasing the density and lowering the Gibbs free energy of the system. This work expands our understanding of the complicated crystallization behavior of GSF in dispersions with PEG and emphasizes the importance of polymorphism control during the manufacturing and storage of PEG-based solid dispersions to achieve reproducible and consistent pharmaceutical performance. The results also suggest that polymer addition is an alternative strategy that cannot be neglected in polymorphism screening.

Bis(1-phenyl-1-propyne) complexes of tungsten(II): crystal structures of [WI2(CO)(NCR)(η2-MeC2Ph)2] (R = Me, Et, or Ph)

2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans
Keyword(s):  
Carbon Monoxide ◽  
Solid State ◽  
Crystal Structures ◽  
Octahedral Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alkyne Complexes ◽  
First Time

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.

scholarly journals Unraveling the long-pursued Au144 structure by x-ray crystallography

2018 ◽  
Vol 4 (10) ◽  
pp. eaat7259 ◽  
Author(s):  
Nan Yan ◽  
Nan Xia ◽  
Lingwen Liao ◽  
Min Zhu ◽  
Fengming Jin ◽  
...  
Keyword(s):  
Metal Nanoparticles ◽  
Weak Interactions ◽  
Gold Nanoclusters ◽  
Atomic Level ◽  
High Quality ◽  
X Ray ◽  
X Ray Crystallography ◽  
Quantum Size ◽  
First Time

The transition from nanocluster to nanocrystal is a central issue in nanoscience. The atomic structure determination of metal nanoparticles in the transition size range is challenging and particularly important in understanding the quantum size effect at the atomic level. On the basis of the rationale that the intra- and interparticle weak interactions play critical roles in growing high-quality single crystals of metal nanoparticles, we have reproducibly obtained ideal crystals of Au144(SR)60 and successfully solved its structure by x-ray crystallography (XRC); this structure was theoretically predicted a decade ago and has long been pursued experimentally but without success until now. Here, XRC reveals an interesting Au12 hollow icosahedron in thiolated gold nanoclusters for the first time. The Au–Au bond length, close to that of bulk gold, shows better thermal extensibility than the other Au–Au bond lengths in Au144(SR)60, providing an atomic-level perspective because metal generally shows better thermal extensibility than nonmetal materials. Thus, our work not only reveals the mysterious, long experimentally pursued structure of a transition-sized nanoparticle but also has important implications for the growth of high-quality, single-crystal nanoparticles, as well as for the understanding of the thermal extensibility of metals from the perspective of chemical bonding.

A phthalocyanine–subphthalocyanine heterodinuclear dimer: comparison of spectroscopic properties with those of homodinuclear dimers of constituting units

2014 ◽  
Vol 50 (23) ◽  
pp. 3040-3043 ◽  
Author(s):  
Norio Shibata ◽  
Satoru Mori ◽  
Masamichi Hayashi ◽  
Masashi Umeda ◽  
Etsuko Tokunaga ◽  
...  
Keyword(s):  
Spectroscopic Properties ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Time

A phthalocyanine–subphthalocyanine heterodinuclear dimer has been disclosed for the first time with its unique flat-bowl-shaped structure revealed by X-ray crystallography.

scholarly journals Sesquiterpene Lactones from Inula oculus-christi

2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Mahmoud Mosaddegh ◽  
Maryam Hamzeloo Moghadam ◽  
Saeedeh Ghafari ◽  
Farzaneh Naghibi ◽  
Seyed Nasser Ostad ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Sesquiterpene Lactones ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Time

Inula oculus-christi L. (Compositae) extract was chromatographed and three sesquiterpene lactones ergolide, gaillardin and pulchellin C were isolated. The structures of these compounds were determined by analysis of their spectroscopic data, and their crystal structures were defined using X-ray crystallography; the isolation of ergolide and pulchellin C is reported for the first time from this species. These three compounds were evaluated for their in vitro cytotoxic activity against MDBK, MCF7 and WEHI164 cells; ergolide and gaillardin exhibited lower and significantly different IC50 values compared with pulchellin C ( p<0.001).

scholarly journals Mechanochemical Synthesis and Structure of the Tetrahydrate and Mesoporous Anhydrous Metforminium(2+)-N,N’-1,4-Phenylenedioxalamic Acid Cocrystal Salt: The Role of Hydrogen Bonding and N→π* Charge Assisted Interactions

2020 ◽  
Author(s):  
Sayuri Chong-Canto ◽  
Efrén V. García-Báez ◽  
Francisco J. Martínez-Martínez ◽  
Ángel Ramos-Organillo ◽  
Itzia I. Padilla-Martínez
Keyword(s):  
Hydrogen Bonding ◽  
Mechanochemical Synthesis ◽  
Water Molecules ◽  
X Ray ◽  
X Ray Crystallography ◽  
Adsorption Desorption ◽  
First Time ◽  
Selective Formation ◽  
Crystallization From Solution

A new cocrystal salt of metformin, an antidiabetic drug, and N,N&rsquo;-(1,4-phenylene)dioxalamic acid, was synthesized by mechanochemical synthesis, purified by crystallization from solution and characterized by single X-ray crystallography. The structure revealed a salt-type cocrystal composed of one dicationic metformin unit, two monoanionic units of the acid and four water molecules namely H2Mf(HpOXA)2∙4H2O. X-ray powder, IR, 13C-CPMAS, thermal and BET adsorption-desorption analyses were performed to elucidate the structure of the molecular and supramolecurar structure of the anhydrous microcrystalline mesoporous solid H2Mf(HpOXA)2. The results suggest that their structures, conformation and hydrogen bonding schemes are very similar between them. To the best of our knowledge, the selective formation of the monoanion HpOXA⁻, as well as its structure in the solid, is herein reported for the first time. Regular O(-)∙∙∙C(), O(-)∙∙∙N+ and bifacial O(-)∙∙∙C()∙∙∙O(-) of n&rarr;* charge-assisted interactions are herein described in H2MfA cocrystal salts which could be responsible of the interactions of metformin in biologic systems. The results, support the participation of n&rarr;* charge-assisted interactions independently, and not just as a short contact imposed by the geometric constraint due to the hydrogen bonding patterns.

scholarly journals Polymorphic G:G mismatches act as hotspots for inducing right-handed Z DNA by DNA intercalation

2019 ◽  
Vol 47 (16) ◽  
pp. 8899-8912 ◽  
Author(s):  
Roshan Satange ◽  
Chien-Ying Chuang ◽  
Stephen Neidle ◽  
Ming-Hon Hou
Keyword(s):  
Actinomycin D ◽  
Single Step ◽  
Dna Intercalation ◽  
Chromomycin A3 ◽  
Dna Structures ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dna Mismatches ◽  
Z Dna ◽  
First Time

Abstract DNA mismatches are highly polymorphic and dynamic in nature, albeit poorly characterized structurally. We utilized the antitumour antibiotic CoII(Chro)2 (Chro = chromomycin A3) to stabilize the palindromic duplex d(TTGGCGAA) DNA with two G:G mismatches, allowing X-ray crystallography-based monitoring of mismatch polymorphism. For the first time, the unusual geometry of several G:G mismatches including syn–syn, water mediated anti–syn and syn–syn-like conformations can be simultaneously observed in the crystal structure. The G:G mismatch sites of the d(TTGGCGAA) duplex can also act as a hotspot for the formation of alternative DNA structures with a GC/GA-5′ intercalation site for binding by the GC-selective intercalator actinomycin D (ActiD). Direct intercalation of two ActiD molecules to G:G mismatch sites causes DNA rearrangements, resulting in backbone distortion to form right-handed Z-DNA structures with a single-step sharp kink. Our study provides insights on intercalators-mismatch DNA interactions and a rationale for mismatch interrogation and detection via DNA intercalation.

scholarly journals The potential benefits of using higher X-ray energies for macromolecular crystallography

2019 ◽  
Vol 26 (4) ◽  
pp. 922-930 ◽  
Author(s):  
Joshua L. Dickerson ◽  
Elspeth F. Garman
Keyword(s):  
Photon Counting ◽  
Incident Beam ◽  
Macromolecular Crystallography ◽  
Silicon Detectors ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cdte Detector ◽  
Potential Benefits ◽  
Incident Beam Energy ◽  
First Time

Using X-ray energies higher than those normally used (5–15 keV) for macromolecular X-ray crystallography (MX) at synchrotron sources can theoretically increase the achievable signal as a function of dose and reduce the rate of radiation damage. In practice, a major stumbling block to the use of higher X-ray energy has been the reduced quantum efficiency of silicon detectors as the X-ray energy increases, but hybrid photon-counting CdTe detectors are optimized for higher X-ray energies, and their performance has been steadily improving. Here the potential advantages of using higher incident beam energy together with a CdTe detector for MX are explored, with a particular focus on the advantages that higher beam energies may have for MX experiments with microbeams or microcrystals. Monte Carlo simulations are presented here which for the first time include the efficiency responses of some available X-ray detectors, as well as the possible escape of photoelectrons from the sample and their entry from surrounding material. The results reveal a `sweet spot' at an incident X-ray energy of 26 keV, and show a greater than factor of two improvement in diffraction efficiency at this energy when using microbeams and microcrystals of 5 µm or less.

Organosulfur oxoacids. Part 1. Synthesis, structure, and reactivity of dimethylaminoiminomethanesulfinic acid (DMAIMSA)

2006 ◽  
Vol 84 (5) ◽  
pp. 825-830 ◽  
Author(s):  
Jonathan F Ojo ◽  
Jeffrey L Petersen ◽  
Adenike Otoikhian ◽  
Reuben H Simoyi
Keyword(s):  
Sulfonic Acid ◽  
Positive Charge ◽  
Strictly Anaerobic ◽  
Single Bond ◽  
Anaerobic Conditions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Acidic Conditions ◽  
The One ◽  
Solid Form

One of the major metabolites of dimethylthiourea, dimethylaminoiminomethanesulfinic acid (DMAIMSA), was synthesized by controlled oxidation of dimethylthiourea using hydrogen peroxide. The crystal structure was determined by X-ray crystallography. It is a zwitterionic species in its solid form, with a positive charge delocalized around an sp2-hybridized carbon center and two nitrogen atoms. It crystallizes in the triclinic P[Formula: see text] space group. The C—S bond, at 1.880(2) Å, is much longer than a typical C—S single bond length of 1.79 Å. It is also longer than the one observed in thiourea trioxide, a comparable sulfonic acid. This C—S bond is stable in acidic conditions and is easily cleaved in basic conditions or in the presence of suitable nucleophiles that can attack the positively disposed carbon center. DMAIMSA is highly reactive and easily decomposes in basic conditions to yield dithionite in the presence of oxygen, whereas in strictly anaerobic conditions it gives a mixture of sulfite and sulfide. The precursor to dithionite, SO2·–, is formed from the one-electron oxidation of the sulfoxylate anion, SO22–, which results from an initial heterolytic cleavage of the C—S bond in DMAIMSA. The sulfur center is oxidized, even by mild oxidants such as aqueous iodine, to sulfate. Key words: thiourea metabolites, synthesis, structure, reactivity.

Cisplatin binding to human serum albumin: a structural study

2015 ◽  
Vol 51 (46) ◽  
pp. 9436-9439 ◽  
Author(s):  
Giarita Ferraro ◽  
Lara Massai ◽  
Luigi Messori ◽  
Antonello Merlino
Keyword(s):  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Crystal Structures ◽  
Structural Study ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Time

The reaction between cisplatin and human serum albumin (HSA) was investigated by X-ray crystallography and crystal structures of the cisplatin/HSA adduct were eventually solved for the first time.

scholarly journals Essential Oil and Major Non-Volatile Secondary Metabolites from the Leaves of Amazonian Piper subscutatum

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1168
Author(s):  
Jorge Ramírez ◽  
María Daniela Andrade ◽  
Giovanni Vidari ◽  
Gianluca Gilardoni
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Secondary Metabolites ◽  
Essential Oil ◽  
Volatile Fraction ◽  
Organic Fraction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ecuadorian Amazon ◽  
First Time

The essential oil and the major non-volatile secondary metabolites from the leaves of Piper subscutatum (Miq.) C. DC. (Family Piperaceae), collected in the Ecuadorian Amazon, were analyzed for the first time in the present study. The essential oil was submitted to chemical and enantioselective analyses by GC-MS and GC-FID. (E)-β-caryophyllene (25.3–25.2%), β-chamigrene (10.3–7.8%), (E)-nerolidol (8.1–7.7%), β-selinene (7.2–7.7%), δ-cadinene (2.7–3.9%), bicyclogermacrene (3.7–2.4%), and β-pinene (2.6–3.4%) were the major components. The enantioselective analysis, carried out on a β-cyclodextrin-based column, showed four scalemic mixtures in which (1R,5R)-(+)-α-pinene, (1S,5S)-(−)-β-pinene, (S)-(−)-limonene, and (1R,2S,6S,7S,8S)-(−)-α-copaene were the major enantiomers, with enantiomeric excesses of 28.8%, 77.8%, 18.4%, and 6.0%, respectively. The study was complemented with the chemical analysis of the organic fraction dissolved in the hydrolate, whose major components were 6-methyl-5-hepten-2-one (63.7–64.4%) and linalool (6.5–6.0%). Concerning the non-volatile fraction, five lignans were the major components. (–)-Beilshminol B, (–)-grandisin, (–)-3′,4′-methylenedioxy-3,4,5-trimethoxy-7,7′-epoxylignan, (–)-3′,4′-methylenedioxy-3,4,5,5′-tetramethoxy-7,7′-epoxylignan, and (–)-3,4,3′,4′-dimethylenedioxy-5,5′-dimethoxy-7,7′-epoxylignan were identified by means of NMR spectroscopy, mass spectrometry and X-ray crystallography. The absolute configuration 7S,8S,7′S,8′S was tentatively assigned to all of them.

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