Synthesis of new 4-(1-ethylthio-2,2,2-trifluoroethyl)-6-methylpyridazin-3(2H)-ones starting from S-ethyl 4-oxo-2-(pentafluoroethyl) pentanethiolate and hydrazines

The paper presents a one-pot conversion of gamma-keto-alpha-pentafluoroethyl thioester into new pyridazin-3-ones and alpha,beta-unsaturated lactams. The structures of all new compounds were ascribed using 1D (F-19, H-1, C-13) and 2D (H-1-N-15) NMR data, and X-ray diffraction analysis. Two possible competitive reaction mechanisms for the synthesis of pyridazin-3-ones and lactams are presented. (C) 2005 Elsevier B.V. All rights reserved

Ortho Effect of One Methyl-group - Conformation of Methyl 5-nitro-2-methylbenzoate in Crystal and in Solution

The x-ray structure of methyl 5-nitro-2-methylbenzoate was determined [M(r) = 195.17, monoclinic, P2(1)/c, a = 7.265(1), b = 7.749(1), c = 16.526(3) angstrom, alpha = 91.50(2)-degrees, V = 930.0(3) angstrom 3, Z = 4, D(x) = 1.39 g cm-3, Cu K-alpha, lambda = 1.5418 angstrom, mu = 9.56 cm-1, F(000) = 408, T = 291 K, R = 0.081 for 1295 observed reflections]. In contrast to the planar molecule of the corresponding acid, studied previously, the carboxylate group in the ester molecule is twisted through an angle 25-degrees from the ring plane. This torsion angle was estimated to be 65-degrees in benzene solution; the estimation was based on the dipole moment and that of methyl 2-methylbenzoate. For the corresponding ethyl esters a value of 79-degrees was found in a similar way. Although these results are expressed in terms of one non-planar conformation, the alternative explanation of an equilibrium of two planar forms is not excluded in solution. The only safe conclusion is that the energy differences are small and the conformation is sensitive both to the conditions and to small changes in structure; a large part of the observed effects of an ortho-methyl group are due to reasons other than to the hindered resonance

Synthesis of new trifluoromethylated furans, dihydrofurans and butenolides starting from gamma-ketothioesters and diisopropylamine

gamma-Ketothioesters were easily transformed into furans, dihydrofurans or butenolides by simple treatment with diisopropylamine in diethyl ether. The Substitution pattern of the starting material has a great influence on the outcome of the reaction. Possible mechanisms for the formation of the heterocycles were proposed. The Structures of all new Compounds were ascribed Using usual NMR data (F-19, H-1, C-13 NMR), X-ray diffraction analysis and H-1-H-1 NOE experiments

The emission and mobilization of Mo from overheated nuclear fuel - the importance of 'maturation' of the aerosols

The chemical properties of radioactive molybdenum dispersed in the environment as a consequence of a nuclear reactor accident depend closely on the reactions taking place in the plume of the reactor or in the confinement building. An oxidizing atmosphere reacting with the aerosols at temperatures of the order of 700 degrees C significantly enhances the solubility of Mo and, as a consequence, its availability to the environment

The Structure and Solid-state Conformation of (e)-(9r,10r)-9,10-epoxy-17-beta-hydroxy 4a-oxa-a-homo-5,10-8,9-disecoandrost-3-ene-5,8-dione Acetate

the molecular structure of the title compound, a 15-membered 9,10-epoxy-3-en-4-ol lactone, which is an important intermediate in the reaction sequence correlating steroid compounds with prostaglandin-like derivatives, was determined by X-ray analysis. The (E) stereochemistry around the double bond and the trans-(9R,10R)-configuration at the oxirane ring are established