Facile Synthesis of 4,5-Dihydro-1,3,4-Thiadiazoles by 1,3-Dipolar Cycloaddition of Thioisomünchnones

2009 ◽  
Vol 62 (4) ◽  
pp. 356 ◽  
Author(s):  
Bárbara Sánchez ◽  
José Luis Bravo ◽  
María Josí Arívalo ◽  
Ignacio López ◽  
Mark E. Light ◽  
...  

The present paper summarizes a straightforward synthesis of 4,5-dihydro-1,3,4-thiadiazoles by the 1,3-dipolar cycloaddition of thioisomünchnones. These reactions have been carried out in dichloromethane and are essentially complete within 60 min at room temperature. Under such mild conditions the asymmetric version has been explored as well. Unequivocal structure elucidation has been accomplished by means of one- and two-dimensional NMR techniques as well as X-ray structure analysis.

2018 ◽  
Vol 74 (9) ◽  
pp. 1186-1189
Author(s):  
Bertin Anzaldo ◽  
Pankaj Sharma ◽  
Francisco Lara Ochoa ◽  
Claudia P. Villamizar C. ◽  
René Gutiérrez Pérez

1,1′-Diformylruthenocene, [Ru(C6H5O)2], crystallizes in the orthorhombic system in the P212121 space group at room temperature. There are two crystallographically independent molecules in the asymmetric unit. The cyclopentadienyl rings have eclipsed configuration. The molecules self-assemble in a two-dimensional structure by C—H...O and C—H...π interactions with cisoid relative orientations of the two formyl groups. The crystal studied was refined as an inversion twin.


RSC Advances ◽  
2015 ◽  
Vol 5 (121) ◽  
pp. 100401-100407 ◽  
Author(s):  
Rajamani Rajmohan ◽  
Subramaniyan Gayathri ◽  
Pothiappan Vairaprakash

In a simple and conceptually designed method for the dehydration of fructose on a solid support, 5-hydroxymethylfurfural (HMF) was synthesized in more than 95% isolated yield from fructose under very mild conditions at room temperature.


2019 ◽  
Vol 5 (8) ◽  
pp. eaaw0982 ◽  
Author(s):  
Zheng-Zhong Zhu ◽  
Zuo-Chang Chen ◽  
Yang-Rong Yao ◽  
Cun-Hao Cui ◽  
Shu-Hui Li ◽  
...  

Carboncones, a special family of all-carbon allotropes, are predicted to have unique properties that distinguish them from fullerenes, carbon nanotubes, and graphenes. Owing to the absence of methods to synthesize atomically well-defined carboncones, however, experimental insight into the nature of pure carboncones has been inaccessible. Herein, we describe a facile synthesis of an atomically well-defined carboncone[1,2] (C70H20) and its soluble penta-mesityl derivative. Identified by x-ray crystallography, the carbon skeleton is a carboncone with the largest possible apex angle. Much of the structural strain is overcome in the final step of converting the bowl-shaped precursor into the rigid carboncone under mild reaction conditions. This work provides a research opportunity for investigations of atomically precise single-layered carboncones having even higher cone walls and/or smaller apex angles.


1998 ◽  
Vol 05 (01) ◽  
pp. 387-392 ◽  
Author(s):  
D. Abriou ◽  
D. Gagnot ◽  
J. Jupille ◽  
F. Creuzet

The growth mode of silver films deposited at room temperature on TiO 2(110) surfaces has been examined by means of atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) in ultrahigh vacuum (UHV) conditions, On clean vacancy-free TiO 2(110) surfaces, 0.1-nm-thick (on average) Ag deposits form a two-dimensional (2D) layer. When the thickness of the silver overlayer is increased, 3D clusters are shown to appear while the 2D film is preserved, furthermore, the influence of surface oxygen vacancies on the growth of Ag/TiO 2(110) is evidenced by well-characterized differences in the morphology of 9-nm-thick silver deposits.


1984 ◽  
Vol 39 (3) ◽  
pp. 341-351 ◽  
Author(s):  
Joseph Grobe ◽  
Gerald Henkel ◽  
Bernt Krebs ◽  
Nikolaos Voulgarakis

Heterocyclic cage compounds of type I (compounds 8-10) have been prepared by condensation reactions of 1,2,2-trifunctional disilanes Me(R)XSiSiMeX2 (R = Me, Ph, OEt; X = NMe2, OEt) with triethanolamine using the “Dilution Principle”. The starting compounds are obtained by Si-Me cleavage of Si2Me6 with acetylchloride/AlCl3 followed by either aminolysis with HNMe2 or alcoholysis with EtOH. 1H NMR spectra indicate N→Si(1) intraction with the more acidic Si atom in 8 and 9. This result is proved by the X-ray structure analysis of 8 (monoclinic, P21/c; a = 7,088(2), b = 15,070(4), c = 12,701(4) Å, β = 104,96(2) at -130 °C, Z = 4); the Si(1)···N distance is found to be 2,768 Å , connected with a significant angular distortion of the tetrahedral coordination around Si(1) towards a trigonal bipyramid. In compound 10, too, N→Si(1) coordination is observed at room temperature in spite of almost equal acidity for both Si atoms. This can be explained by the preference of 5- over 6-membered chelating ring systems. At higher temperatures the 1H NMR spectra show a fluctuation of the N-donor between the two Si centres.


2013 ◽  
Vol 686 ◽  
pp. 86-91 ◽  
Author(s):  
Ahmad Abdolahi ◽  
Esah Hamzah ◽  
Zaharah Ibrahim ◽  
Shahrir Hashim

In this paper, the simple synthesis of polyaniline/silver composites through interfacial polymer method was studied. Polyaniline-silver composites were produced at room temperature by using ammonium persulphate as an oxidant agent in presence of silver nitrate (AgNO3). Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques were used to characterize the synthesized product. FESEM results showed the core shell shape of composites that the layer of polyaniline covered the silver particles. XRD results showed the high crystalline behaviour of the polyaniline/silver composites due to presence of silver. FTIR results also showed the successfully synthesis of the composite. This paper aims to study on synthesis and characterization of polyaniline-silver composites.


1998 ◽  
Vol 53 (3) ◽  
pp. 333-348 ◽  
Author(s):  
Nils Wiberg ◽  
Kerstin Amelunxen ◽  
Hans-Wolfram Lemer ◽  
Heinrich Nöth ◽  
Jörg Knizek ◽  
...  

Abstract Water and oxygen sensitive compounds (tBu3SiEX2)2, tBu3SiEX2 Do and (tBu3Si)2EX (E = AI, Ga, In; X = (F), Cl, Br; Do = OR2, NR3) have been synthezised by reaction of EX3 with tBu3SiNa in the absence or presence of donors. In addition, (tBu3Si)AlBr2, (tBu3Si)2InF and tBu3SiInBr2 were prepared by reaction of AlBr3 with (tBu3Sij2Zn or of (tBu3Si)2In- In(Si/Bu3)2 with AgF2 and HBr, respectively. The adduct [tBu3SiAlBr2 · AlBr3 ·1/2MgBr2]2 is formed from AlBr3 and (tBu3Si)2Mg(THF)2. Thermal decomposition of the compounds in solution or in the gas phase leads to the formation of tBu3SiEX2 (from the dimers or the donor adducts) and of tBu3SiX. The Lewis acidity of tBu3SiEX2 against donors increases in the direction Do = Et2O < THF < NEtMe2. Dehalogenation of (tBu3Si)2ECl with tBu3SiNa(THF)2 in pentane at room temperature leads to clusters (tBu3Si)4Al2, (tBu3Si)3Ga2•, (tBu3Si)4In2 and (tBu3Si)3Ga2Na(THF)3, reduction of tBu3SiGaCl2 with Na or K in heptane at 100°C to the tetrahedran (tBu3Si)4Ga4. The structures of (tBu3SiGaCl2)2, (tBu3Si)2GaCl, and [tBu3SiAlBr2 AlBr3 ·1/2MgBr2]2 have been determined by X-ray structure analysis.


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