13664-05-6Relevant articles and documents
The squaric acid derivatives C8O4S2 and C8O4Se2 - Crystal structures, explosive thermal behavior and the preparation of carbon suboxide selenide OC3Se by flash vacuum pyrolysis
Beck, Johannes,Krieger-Beck, Petra,Kelm, Klemens
, p. 123 - 132 (2006)
2,7-Diselenatricyclo[6.2.0.03.6]deca-1,3-diene-4,5,9,10- tetraone, C8O4Se2, was prepared from 1,2-diselenosquarate and squaric acid dichloride. Its crystal structure and the structure of the already known sulfur analogue C8O4S 2 were determined (C8O4S2: orthorhombic, Pca21, a = 1413.64(2), b = 599.850(9), c = 968.8(1) pm; C8O4Se2: orthorhombic, Pnnm, a = 415.46(2), b = 894.29(5), c = 1160.14(7) pm). The structures are not isotypic and show a different packing of the molecules whose symmetry deviate only slightly from D2h. In the four-membered C4 rings the C-C bonds represent one single bond, one double bond and two slightly shortened single bonds. The C4 rings are thus to be considered as cyclobutene-dione fragments. The vigorous exothermic decomposition of the compounds that occurs on heating to 220 to 240 °C shows that both are energetic materials. The explosions are accompanied by a heat evolution of -192 kJ/mol for C8O 4S2 and -224 kJ/mol for C8O4Se 2. Performing the decomposition of C8O4S 2 in a closed autoclave leaves a residue of the composition "C6S" which was examined by transmission electron microscopy techniques and shown to consist mainly of amorphous carbon. This thermal behaviour is limiting the utilization of C8O 4S2 and C8O4Se2 as precursors for the syntheses of OC3S and the yet unknown OC 3Se via FVP. The formation of OC3S could be proven by the reaction of the trapped, slightly yellow product (evaporation at 200 °C, pyrolysis at 500 °C, trapping at -196 °C) with aniline which yielded thiomalonic acid dianilide, of which the crystal structure was determined (monoclinic, C2/c, a = 2814.8(16), b = 1201.7(8), c = 809.2(4) pm, β = 91.88(4)°, V = 2736(3) · 106 pm3). The mass spectrum of C8O4Se2 shows the strongest signal for OC3Se+, and FVP experiments (evaporation at 220 °C, pyrolysis at 650 °C, trapping at -75 °C) yielded small amounts of a bright yellow material which rapidly converted into a black polymer.
Elemental Sulfur/DMSO-Promoted Multicomponent One-pot Synthesis of Malonic Acid Derivatives from Maleic Anhydride and Amines
Nguyen, Le Anh,Retailleau, Pascal,Nguyen, Thanh Binh
supporting information, p. 2864 - 2869 (2019/05/01)
Malonic acid derivatives could be conveniently prepared with high degree of functional flexibility via redox condensation reactions between anhydride maleic, amines, elemental sulfur and DMSO as oxidant. This multicomponent decarboxylative transformation consists in a cascade of ring opening, decarboxylative oxidative thioamidation at temperature as low as 50 °C. (Figure presented.).
Preparation of pseudo-peptide building blocks with retro-thioamide bond mediated via thiocarbamoyl Meldrum's acid
Janikowska, Karolina,Makowiec, Slawomir,Rachon, Janusz
, p. 461 - 468 (2012/05/04)
An easy and efficient synthesis of pseudo-tripeptide containing a thiomalonamide moiety was developed. Isothiocyanate derivatives of amino acids react smoothly with 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid) to yield new thiocarbamoyl derivatives of Meldrum's acids. Thermal decomposition of these new derivatives leads to thiocarbamoyl ketenes, which acylate amino acid esters to give pseudo-tripeptides. Copyright
A facile and practical one-pot synthesis of β-oxo thioamides from β-oxo amides and isothiocyanates
Huang, Peng,Xiang, Dexuan,Zhou, Yang,Liang, Yongjiu,Na, Tianhai,Dong, Dewen
experimental part, p. 1797 - 1800 (2010/03/30)
A facile and practical one-pot synthesis of β-oxo thioamides from β-oxo amides has been developed. By treatment with isothiocyanates in ethanol in the presence of potassium carbonate, a series of β-oxo amides was converted, under reflux, in high yields in
REAKTIVITAET DER 1,3-DITHIETHANDERIVATIVE
Zankowska-Jasinska, W.,Galuszka, B.
, p. 165 - 174 (2007/10/02)
The acidic hydrolysis of 'cis' and 'trans' isomers of 2,4-bis-(phenylcarbamoyl-benzaniline-methylene)-1,3-dithiethane causes the cleavage of Schiff bases moieties.Products were made to react with aniline and also hydrolyzed by alkaline.
