scholarly journals Synthesis and Configurational Character Study of Novel Structural Isomers Based on Pyrene–Imidazole

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2293
Author(s):  
Yu-Long Liu ◽  
Liu Yang ◽  
You-Quan Guo ◽  
Guo-Qiang Xu ◽  
Bin Qu ◽  
...  

Isomers provide more possibilities for the structure of organic compounds. Molecular structures determine their corresponding properties, therefore the intrinsic relationship between structure and properties of isomers is of great research value. Isomers with a stable structure and excellent performance possess more potential for development and application. In this paper, we design and synthesize structural isomers with different molecular symmetries based on the asymmetric structure of imidazole and the symmetrical structure of pyrene. Isomers with stable molecular structures can be obtained by a simple and efficient “one-pot” reaction, involving axisymmetric configuration and centrosymmetric configuration. Using this “click-like” reaction, the structure of target molecules is controllable and adjustable. Furthermore, the effect of molecular configurations on molecular stacking of crystal is studied. The variation of the optical and thermal properties, the optimized structures, and orbital distributions of isomers depends on different molecular geometry with different symmetry, which are revealed by crystallographic analysis. This present strategy provides an efficient synthetic method for the design and synthesis of structural isomers based on pyrene–imidazole.

2017 ◽  
Vol 41 (7) ◽  
pp. 384-389 ◽  
Author(s):  
Yang Huijuan ◽  
Ren Yujie ◽  
Xu Wenqian ◽  
Li Ren

Thirty-two novel 2-amino-1-[3-oxo-3-(substituted-anilino)propyl]pyridinium nitrate derivatives were designed and prepared via one-pot tandem reactions. The structure of the 2-methylanilino derivative was characterised by X-ray crystallographic analysis. In addition, a potential formation mechanism is proposed.


1995 ◽  
Vol 73 (6) ◽  
pp. 835-845 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Ulf Riebe ◽  
Steven J. Rettig ◽  
James Trotter

The diphenylboron chelates of ketoxime adducts to formaldehyde and trichloroacetaldehyde (chloral) have been synthesized. The reactions were carried out as three-component one-pot reactions, and also as two-step reactions for the ketoxime chloral adducts, which were isolated and characterized before reaction with oxybis(diphenylborane) to form the diphenylboron chelates. One of the intermediate adducts and two of the diphenylboron chelates have been characterized by X-ray crystallographic analysis. Crystals of O-(2,2,2-trichloro-1-hydroxyethyl)-2-propanonoxime, 8d, are monoclinic, a = 7.010(2), b = 11.832(3), c = 11.684(2) Å, β = 90.48(2)°, Z = 4, space group P21/c; those of 4-isopropylidene-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 9a, are orthorhombic, a = 11.098(2), b = 15.364(1), c = 8.715(2) Å, Z = 4, space group P212121; and those of 5-trichloromethyl-2-isopropylidene-3,3-diphenyl-1,4-dioxa-2-azonia-3-boratacyclopentane, 10d, are monoclinic, a = 9.164(2), b = 15.304(3), c = 13.859(2) Å, β = 105.28(1)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R = 0.037, 0.044, and 0.040 (Rw = 0.041, 0.016, and 0.042) for 1082, 1256, and 3062 reflections with I ≥ 3σ(F2), respectively. The X-ray analyses show that the products from the reaction between acetonoxime, oxybis(diphenylborane), and formaldehyde or trichloroacetaldehyde, respectively, possess different boron chelate structures. With formaldehyde a COBON chelate ring is obtained and with trichloroacetaldehyde a BOCON chelate ring is formed. Keywords: boron chelates, boron compounds, organboron compounds, crystal structures.


2021 ◽  
Vol 22 (15) ◽  
pp. 8191
Author(s):  
Fumihiro Kawagoe ◽  
Sayuri Mototani ◽  
Atsushi Kittaka

The discovery of a large variety of functions of vitamin D3 and its metabolites has led to the design and synthesis of a vast amount of vitamin D3 analogues in order to increase the potency and reduce toxicity. The introduction of highly electronegative fluorine atom(s) into vitamin D3 skeletons alters their physical and chemical properties. To date, many fluorinated vitamin D3 analogues have been designed and synthesized. This review summarizes the molecular structures of fluoro-containing vitamin D3 analogues and their synthetic methodologies.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Corina E. Brown ◽  
Ben Whaley ◽  
Richard M. Hyslop

AbstractThe purpose of this study was to compare the effectiveness of three methods used to assist in teaching molecular geometry to college chemistry students. A pre- and post-test quasi-experiment was used to collect data about students’ performance in a given chemistry exercise. One research question was intended to evaluate and compare the effectiveness of the three methods in assisting students to understand the topic and carry out the exercise correctly, and a second research question addressed students’ attitudes towards the use of Virtual Reality (VR) in chemistry education. Results show a positive attitude towards the use of VR as an assisting tool to aid in understanding chemistry concepts. While the difference among the three methods was not significant, the results show that the VR brought more enthusiasm and positive attitudes toward the topic of molecular geometry among the students. Educational implications and recommendations for future research are presented as well.


2018 ◽  
Vol 57 (44) ◽  
pp. 14967-14976 ◽  
Author(s):  
Cheng Peng ◽  
Jian Liang ◽  
Honggen Peng ◽  
Ran Yan ◽  
Wenming Liu ◽  
...  

Synthesis ◽  
2018 ◽  
Vol 51 (01) ◽  
pp. 40-54 ◽  
Author(s):  
Masahito Murai ◽  
Kazuhiko Takai

Recent advancements in unsymmetrical difunctionalization based on the substitution of two different C–H bonds in one-pot are described. Due to the difficulty of controlling reactivity and selectivity, multi-functionalization via substitution of several C–H bonds to install different functional groups has been limited until recently, in comparison with well-studied functionalization via sequential addition to unsaturated π-bonds. This difunctionalization protocol provides an efficient and rapid approach to a library of structurally complicated target molecules through the formation of multiple C–X bonds with high atom- and step-economy.1 Introduction2 ortho-Selective Functionalization of Two Different C–H Bonds Relative to the Directing Group2.1 Unsymmetrical Difunctionalization with the Introduction of Similar Functional Groups2.2 Unsymmetrical Difunctionalization with the Introduction of Different Functional Groups2.3 ortho-Selective Unsymmetrical Difunctionalization Promoted by Two Different Directing Groups Appearing During the Progress of the Reaction3 ortho/meta-Selective C–H Bond Difunctionalization Relative to the Directing Group4 Sequential Difunctionalization of Fused Aromatic Compounds and Heterocycles5 Summary and Outlook


Author(s):  
O. Bugera ◽  
A. Netrebchuk ◽  
V. Pivovarenko

Adenosine 5'-triphosphate (ATP) is known as a universal energy source and signaling mediator in numerous biological processes. Among the methods for its determination, molecular fluorescence probes occupy leading positions due to high sensitivity and selectivity. Recently we have shown that 31 of 33 tested flavones and quinolones of various structures give fluorescence response and can be effectively applied as the probes in aqueous solutions for detection of ATP in 1–50,000 μM range of its concentrations. To increase response parameters of a probe in respect to ATP we have synthesized N,N'-(butane-1,4-diyl)bis(2-((2-(4-(dimethylamino)phenyl)-3-hydroxy-4-oxo-4H-chromene-6-yl)oxy)acetamide, the molecular tweezer composed of two flavonol units connected by active linker. On our idea, being equipped by two planar platforms, the tweezershould demonstrate increased affinity and selectivity to ATP in a result of increased number of hydrogen bonds and increased stacking interactions. Having two NH-amide groups the amino acid linker will form hydrogen bonds with the phosphates of ATP, increasing the portion of probe-ATP complex population in the reporting conformation.In the four-step synthesis of this molecular device, starting from methyl 2-(3-acetyl-4-hydroxyphenoxy)acetate and N,N-dimethylaminobenzaldehyde, the conditions for the reaction of one-pot chalcone formation and its oxidative heterocyclization in the presence of an organic base were found, which resulted in the isolation of a target flavonol-amino acid derivative with high yields. We suggest that atmospheric oxygen was an oxidizer in this process. The obtained derivative was converted intotarget compound by dual condensation with 1,4-butane diamine.


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