Detail of "2892-62-8"

Reference

Pharmacology, toxicology, and immunology of experimental contact sensitizers

Pharmacology, toxicology, and immunology of experimental contact sensitizers. Hannon, Whitney; Chartier, Tim; Taylor, J. Richard (School of Medicine, University of Miami, Miami, FL, USA). Toxicology of Skin, 271-291. Edited by: Maibach, Howard I. Taylor & Francis, Inc.: Philadelphia, Pa. ISBN: 1-56032-802-9(English) 2001. CODEN: 69EDSG. DOCUMENT TYPE: Conference; General Review CA Section: 4 (Toxicology) A review discusses the basic pharmacol., toxicol. 2892-62-8 and 97-00-7 are cas registry numbers of chemicals which are used as reagents here., and immunol. of the three most well characterized three-contact sensitizers: dinitrochlorobenzene (DNCB), diphenylcyclopropranone, and squaric acid dibutylester (SADBE). Current knowledge suggest, that DNCB is the best characterized chem. and has superior stability, but is genotoxic and therefore should be used with careful consideration of clin. risks and benefits. DPCP and SADBE are less well characterized and more unstable. .

The squaric acid derivatives C8O4S2 and C8O4Se2 - crystal structures, explosive thermal behavior and the preparation of carbon suboxide selenide OC3Se by flash vacuum pyrolysis

All Rights Reserved. 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 (Institute for Inorganic Chemistry, Rheinische Friedrich-Wilhelms-Universitat Bonn, Bonn D-53121, Germany). Zeitschrift fuer Naturforschung, B: Chemical Sciences, 61(2), 123-132 (English) 2006 Verlag der Zeitschrift fuer Naturforschung. CODEN: ZNBSEN. ISSN: 0932-0776. DOCUMENT TYPE: Journal CA Section: 28 (Heterocyclic Compounds (More Than One Hetero Atom)) Section cross-reference(s): 25, 75 2,7-Diselenatricyclo[6.2.0.03.6]deca-1,3-diene-4,5,9,10-tetraone, C8O4Se2, was prepd. from 1,2-diselenosquarate and squaric acid dichloride. Its crystal structure and the structure of the already known sulfur analog C8O4S2 were detd. (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 mols. 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. 13664-05-6 and 2892-62-8 which are cas registry numbers are also used here. The vigorous exothermic decompn. of the compds. that occurs on heating to 220 to 240° shows that both are energetic materials. The explosions are accompanied by a heat evolution of -192 kJ/mol for C8O4S2 and -224 kJ/mol for C8O4Se2. Performing the decompn. of C8O4S2 in a closed autoclave leaves a residue of the compn. "C6S" which was examd. by transmission electron microscopy techniques and shown to consist mainly of amorphous carbon. This thermal behavior is limiting the utilization of C8O4S2 and C8O4S2 as precursors for the syntheses of OC3S and the yet unknown OC3Se via FVP. The formation of OC3S could be proven by the reaction of the trapped, slightly yellow product (evapn. at 200°, pyrolysis at 500°, trapping at -196°) with aniline which yielded thiomalonic acid dianilide, of which the crystal structure was detd. (monoclinic, C2/c, a = 2814.8(16), b = 1201.7(8), c = 809.2(4) pm, b = 91.88(4)°, V = 2736(3) × 106 pm3). The mass spectrum of C8O4Se2 shows the strongest signal for OC3Se+, and FVP expts. (evapn. at 220°, pyrolysis at 650°, trapping at -75°) yielded small amts. of a bright yellow material which rapidly converted into a black polymer. .