scholarly journals Synthesis and Crystal Structures of 4,5-Dihydroimidazo[1,5-b]pyrazol-6-ones

SynOpen ◽  
2020 ◽  
Vol 04 (04) ◽  
pp. 71-83
Author(s):  
Antonio Guirado ◽  
María Vera ◽  
Bruno Martiz ◽  
Francisco Ródenas ◽  
José A. Sandoval ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Hydrogen Chloride ◽  
Pyrazole Ring ◽  
Crystallographic Analysis ◽  
Ring System ◽  
X Ray ◽  
One Step ◽  
Chloride Elimination

AbstractThe synthesis of previously unattainable 2,5-disubstituted 4,5-dihydroimidazo[1,5-b]pyrazol-6-ones has been developed. Electrochemical reductions of readily available 2,2,2-trichloroethylideneacetophenones were followed by reaction with hydrazine, leading to 3-aryl-5-dichloromethyl-2-pyrazolines. These were treated with isocyanates to obtain the corresponding aminocarbonyl derivatives, which were found to be able to form an otherwise almost inaccessible imidazo[1,5-b]pyrazole ring system via a one-step reaction involving internal condensation followed by hydrogen chloride elimination and aromatization. The molecular­ structures of 2-(4-methylphenyl)-5-tosyl-4,5-dihydro­imidazo[1,5-b]pyrazol-6-one, 5-dichloromethyl-N-(4-chlorophenyl)-4,5-dihydro-3-p-tolylpyrazole-1-carboxamide, and 5-(4-bromophenyl)-2-p-tolyl-4,5-dihydroimidazo[1,5-b]pyrazol-6-one were determined by X-ray crystallographic analysis.

Imidazole/benzimidazole-modified cyclotriphosphazenes as highly selective fluorescent probes for Cu2+: synthesis, configurational isomers, and crystal structures

2017 ◽  
Vol 46 (28) ◽  
pp. 9140-9156 ◽  
Author(s):  
Aylin Uslu ◽  
Süreyya Oğuz Tümay ◽  
Ahmet Şenocak ◽  
Fatma Yuksel ◽  
Elif Özcan ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Fluorescent Probes ◽  
Copper Ion ◽  
Crystallographic Analysis ◽  
Ion Detection ◽  
X Ray

We present a comprehensive work and discuss the fluoroprobe properties of synthesized compounds for copper ion detection with a stereochemical approach using X-ray crystallographic analysis results.

The Structure of the Decalone Obtained From the Oxidation of Guaiol

1992 ◽  
Vol 45 (2) ◽  
pp. 327 ◽  
Author(s):  
RM Carman ◽  
AC Garner ◽  
WT Robinson
Keyword(s):  
Transition State ◽  
Crystallographic Analysis ◽  
Ring System ◽  
X Ray ◽  
Fused Ring ◽  
Fused Ring System ◽  
Insight Into

The structure of the decalone previously reported from the oxidation of guaiol has, after X-ray crystallographic analysis, been revised to structure (3c) which contains a cis -fused ring system. Deuteration studies give insight into the conformation of the transition state during the reaction.

Intramolecular Hydrolysis of Coordinated Acetonitrile in a Binuclear Complex of Cobalt(III): X-Ray Crystallographic Analysis of Salts of [(tren)Co(μ-NH2,μ-L)Co(tren)]4+(L=OH, CH3C(O)NH)

1990 ◽  
Vol 43 (4) ◽  
pp. 643 ◽  
Author(s):  
NW Alcock ◽  
II Creaser ◽  
NJ Curtis ◽  
L Roecker ◽  
AM Sargeson ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Binuclear Complex ◽  
Binding Mode ◽  
Crystallographic Analysis ◽  
Bridging Ligands ◽  
X Ray ◽  
Hydrolysis Of

A synthesis of [( tren )Co(μ-NH2,μ-OH)Co( tren )]4+(3)( tren = tris (2- aminoethyl )amine) is reported along with a series of derivatives: [( tren ) XCo (μ-NH2) CoX ( tren )]n+, where X = CF3SO3- (n = 3)(4), X = CH3CN (n = 5)(5), and [( tren )Co(μ-NH2,μ-CH3C(O)NH)Co( tren )]4+ (6). The substitution of (4) by CH3CN to yield (5) was studied in CH3CN at 20°C, k = 9.0×10-3 s-1, and the intramolecular hydrolysis of (5) to yield the bridging acetamide complex (6) was studied at various acid concentrations. The X-ray crystal structures were determined for (3b) (exafluorophosphate, dihydrate) and (6b) (dithionate, tetrahydrate ). Both crystals are monoclinic, respectively P21/n with a 11.082(2), b 10.402(2), c 15.611(2)Ǻ, β 99.13(2)°, Z 2, and C2/c with a 14.328(2), b 14.046(1), c 16.497(2)Ǻ, β 101.90(1)°, Z 4. For the salt of (3), 2389 data with 1 ≥ 2σ(I) were refined to R 0.070 ( Rw 0.066), and, for the salt of (6), 3087 data with I ≥ 3σ(I) were refined to R 0.041 ( Rw 0.056). Both ions lie on pseudo-symmetric sites involving disorder of the bridging ligands . The structures establish the binding mode of the acetamido ion and the orientation of the tren groups in the isolated complexes.

Chemistry and crystal structures of tetrabenzoylethylene, its photolysis product and tetraacetylethylene

1978 ◽  
Vol 31 (6) ◽  
pp. 1265 ◽  
Author(s):  
JR Cannon ◽  
VA Patrick ◽  
CL Raston ◽  
AH White
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Molecular Conformation ◽  
Crystallographic Analysis ◽  
Stable Form ◽  
Photolysis Product ◽  
Molecular Conformations ◽  
X Ray ◽  
The Difference ◽  
The Stability

X-ray crystallographic analysis has revealed that the light-sensitive form (A) and the light-stable form (A') of tetrabenzoylethylene are not valence tautomers but are two crystalline modifications of the same substance. The difference in the stability of these forms to light appears to be a consequence of their different molecular conformations and packing in the solid state. The molecular conformation of the A form is represented by (8) and that of the A' form by (9). The related tetraacetylethylene has the conformation (10) in the solid state. X-ray crystallographic analysis has also revealed that the photolysis product (B) of tetrabenzoylethylene is 4-phenoxy-3,4,6-triphenyl-1H,4H-furo[3,4-c]-furan-1-one (11). ��� The crystal structures of (8), (9), (10) and (11) were determined by X-ray diffraction: diffractometer data at 295 K were refined by least-squares techniques to residuals of 0.064 (2161 'observed' reflections) for (8), 0.057 (1310) for (9), 0.049 (1295) for (10) and 0.061 (1639) for (11). Crystals of (8) are monoclinic, P21/n, a 8.775(5), b 17.352(9), c 30.985(8)Ǻ, β 93.01(3)°, Z 8. Crystals of (9) which contain carbon disulfide are monoclinic, A2/a, a 21.21(2), b 6.181(4), c 20.35(2) Ǻ, β 102.77(7)°, Z 4. Crystals of (10) are monoclinic, P21/n, a 7.540(2), b 4.392(2), c 14.770(4) Ǻ, β 96.29(2)°, Z 2. Crystals of (11) are monoclinic, P1/n, a 14.820(4), b 15.000(3), c 10.819(4)Ǻ, β 106.02(2)°, Z 4.

Stereoselective synthesis and X-ray crystallographic analysis of mixed 6,6-dihalo penicillanates

1985 ◽  
Vol 63 (11) ◽  
pp. 3177-3181 ◽  
Author(s):  
Diego U. Belinzoni ◽  
Oreste A. Mascaretti ◽  
Pedro M. Alzari ◽  
Graciela Punte ◽  
Carlos Faerman ◽  
...  
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Stereoselective Synthesis ◽  
Crystallographic Analysis ◽  
Displacement Reaction ◽  
X Ray ◽  
Single Crystal Analysis

The pivaloyloxy methyl 6,6-dihalo penicillanates 1a, 1b, and 1c have been stereoselectively prepared from the reaction of pivaloyloxy methyl 6-diazo penicillanate 2 with either N-halosuccinimide/halide or the interhalogens Xl (X = Cl, Br). The crystal structures of 3S,5R,6R pivaloyloxy methyl 6-bromo, 6-chloro penicillanate1a; 3S,5R,6R pivaloyloxy methyl 6-iodo, 6-bromo penicillanate 1b, and 3S, 5R, 6R pivaloyloxymethyl 6-iodo, 6-chloro penicillanate 1c have been determined by X-ray single crystal analysis. The stereochemistry of the displacement reaction is discussed.

scholarly journals Structural and morphological tuning of Cu-based metal oxide nanoparticles by a facile chemical method and highly electrochemical sensing of sulphite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Velayutham Sudha ◽  
Govindhasamy Murugadoss ◽  
Rangasamy Thangamuthu
Keyword(s):  
Crystal Structures ◽  
Chemical Method ◽  
Metal Oxide Nanoparticles ◽  
Modified Electrodes ◽  
Electrochemical Sensing ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
One Step

AbstractA facile one-step chemical method is introduced for the successful synthesis of Cu2O, CuO and CuNa2(OH)4 crystal structures and their electrochemical properties were also investigated. X-ray diffraction studies revealed that these copper-based oxide nanoparticles display different crystal structures such as cubic (Cu2O), monoclinic (CuO) and orthorhombic [CuNa2(OH)4]. The microstructural information of nanoparticles was investigated by transmission electron microscopy. It shows attractive morphologies of different orientation such as rod like structure, nanobeads and well-aligned uniform nanorod for Cu2O, CuO and CuNa2(OH)4, respectively. Electrochemical sensing of sulphite (SO32−) on these three copper-based oxide modified electrodes was investigated. Among the three different crystal structures, CuO shows promising electrocatalytic activity towards oxidation of sulphite. A linear variation in peak current was obtained for SO32− oxidation from 0.2 to 15 mM under the optimum experimental condition. The sensitivity and detection limit were in the order of 48.5 µA cm−2 mM−1 and 1.8 µM, respectively. Finally, practical utility of CuO modified electrode was demonstrated for the estimation of sulphite in commercial wine samples.

Convenient Synthesis of New Heterocycles Containing the Quinoxaline Ring System

2020 ◽  
Vol 17 (2) ◽  
pp. 121-126
Author(s):  
Hanan A. Mohamed ◽  
Mohammad Hayal Alotaibi ◽  
Benson M. Kariuki ◽  
Gamal A. El-Hiti
Keyword(s):  
Crystal Structures ◽  
Ring System ◽  
Synthetic Methods ◽  
Spectroscopic Methods ◽  
X Ray ◽  
Convenient Synthesis ◽  
Current Article ◽  
New Compounds ◽  
Quinoxaline Ring

: The aim of the current article was to describe simple procedures for the synthesis of new heterocycles incorporating the quinoxaline moiety using benzene-1,2-diamine and quinoxaline-2,3- dithiol as precursors. Simple synthetic methods are described for the synthesis of new heterocycles using commercially available chemicals. Also, the new compounds were determined using analytical and spectroscopic methods including single X-ray crystal structures. A series of new heterocycles containing the quinoxaline nucleus have been synthesized in good yields using simple and convenient procedures. A process has been described for the synthesis of new heterocycles containing the quinoxaline moiety that might be difficult to synthesize by other routes.

scholarly journals Frq2 fromDrosophila melanogaster: cloning, expression, purification, crystallization and preliminary X-ray analysis

2014 ◽  
Vol 70 (4) ◽  
pp. 530-534 ◽  
Author(s):  
Soledad Baños-Mateos ◽  
Antonio Chaves-Sanjuán ◽  
Alicia Mansilla ◽  
Alberto Ferrús ◽  
María José Sánchez-Barrena
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Crystal Structures ◽  
Calcium Binding ◽  
Crystallographic Analysis ◽  
Differential Function ◽  
Crystal Forms ◽  
X Ray ◽  
Seeding Method ◽  
Chromatographic Procedure

Drosophila melanogastercontains two calcium-binding proteins, Frq1 and Frq2, in the nervous system that control the number of synapses and the probability of release. To understand the differential function of the two proteins, whose sequence is only 5% dissimilar, the crystal structures of Frq1 and Frq2 are needed. Here, the cloning, expression, purification, crystallization and preliminary crystallographic analysis of Frq2 are presented. The full-length protein was purified using a two-step chromatographic procedure. Two different diffracting crystal forms were obtained using a progressive streak-seeding method and detergents.

scholarly journals Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

2019 ◽  
Vol 15 ◽  
pp. 679-684 ◽  
Author(s):  
Vaida Milišiūnaitė ◽  
Rūta Paulavičiūtė ◽  
Eglė Arbačiauskienė ◽  
Vytas Martynaitis ◽  
Wolfgang Holzer ◽  
...  
Keyword(s):  
Pyrazole Ring ◽  
Ring System ◽  
Ring Closure ◽  
X Ray Diffraction ◽  
Efficient Procedure ◽  
Ring Systems ◽  
X Ray ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Derivatives Of

Fused pyrazole ring systems are common structural motifs of numerous pharmaceutically important compounds. Nevertheless, access to derivatives of the aromatic 2H-furo[2,3-c]pyrazole ring system is still quite limited, and their chemistry and functional properties remain largely underexplored. The current study investigates routes to construct this system from easily accessible starting materials using metal-catalyzed reactions. A simple and efficient procedure to access the 2H-furo[2,3-c]pyrazole ring system was developed by employing the silver(I) ion-mediated ring-closure reaction of 4-alkynyl-3-hydroxy-1-phenyl-1H-pyrazoles as a key step. The required intermediate hydroxyalkynyl substrates for this reaction were prepared by a Pd-catalyzed coupling of 4-iodo-1-phenyl-1H-pyrazol-3-ol with ethyne derivatives. The structures of the obtained target compounds were unequivocally confirmed by detailed 1H, 13C and 15N NMR spectroscopic experiments, HRMS and a single-crystal X-ray diffraction analyses. This silver(I)-mediated 5-endo-dig cyclization of readily available 4-alkynyl-3-hydroxy-1H-pyrazoles can be used as an efficient method to access many novel 2,5-disubstituted 2H-furo[2,3-c]pyrazoles.

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