19676-39-2Relevant academic research and scientific papers
Quaternary ammonium polychlorides as efficient reagents for chlorination of unsaturated compounds
Zelikman,Tyurin,Smirnov,Zyk
, p. 1541 - 1546 (2007/10/03)
Chlorination of unsaturated compounds by benzyltributylammonium polychlorides results in higher yields of addition products compared to those obtained with molecular chlorine.
Reaction of Phosphorus Pentachloride with 2-Acetylthiophene and Acetophenone
Kagan, Jaques,Arora, Sudershan K.,Bryzgis, Marius,Dhawan, Som N.,Reid, Kevin,et al.
, p. 703 - 706 (2007/10/02)
The treatment of 2-acetylthiophene with PCl5, followed by dehydrochlorination, is known to be a poor method for synthesizing 2-ethynylthiophene (1a).Reinvestigation of the reaction showed the major products to be the E- and Z- isomers of 1,2-dichloro-1-(2-thienyl)ethylene (7a), with minor amounts of 1,1-dichloro-1-(2-thienyl)ethane (3a), 1-chloro-1-(2-thienyl)ethylene (4a), 2-(chloroacetyl)thiophene, and 2-(dichloroacetyl)thiophene.The treatment of acetophenone with PCl5 yielded similar products, and the mechanism of these reactions is discussed.The major product 7a could be converted into 1a by reaction with magnesium.The yield of 4a was increased when pyridine was also used, when only 1 equiv of PCl5 was added by portions to the ketone, or when catecholphosphorus trichloride was used instead of PCl5.The best method for converting 2-acetylthiophene into 1a goes through the enol phosphonate of 2-(bromoacetyl)thiophene, which is treated with sodium amide.
Synthetic Applications of Conjugated Azocarbinols. Radical Chain Hydrophenylation and Hydrocyclohexenylation of Haloethenes
Chang, Yau-Min,Profetto, Ralph,Warkentin, John
, p. 7189 - 7195 (2007/10/02)
2-(Phenylazo)-2-propanol (5) and (phenylazo)diphenylmethanol (6) decompose in solution by process involving phenyl radicals.Similarly, 1-(1-azocyclohexenyl)cyclohexanol (7) decomposes to generate the 1-cyclohexenyl radical.Evidence for radical intermediates includes the formation of chlorobenzene and 1-chlorocyclohexene, respectively, from decomposition of 5 (or 6) and 7 in CCl4.Evidence for induced, chain decomposition by radical abstraction of hydroxyl hydrogen, in concert with breaking of at least one C-N bond of the azo function, includes faster decomposition in CCl4 than in benzene, acceleration of decomposition in CCl4 by thiophenol, and acceleration of decomposition in benzene by trityl radicals.That decomposition mechanism is supported also by the finding that methyl ethers and acetate esters of the azoalcohols decompose much more slowly than the alcohols themselves.Phenyl radicals from either 5 or 6, and 1-cyclohexenyl radicals from 7, can be trapped with some alkene by addition.Such radical adducts subsequently pick up a hydrogen atom, presumably by abstracting from the hydroxyl group of the azocarbinol in concert with C-N bond breaking.The overall processes, then, are hydrophenylation of alkenes with 5 and 6 and hydro-1-cyclohexenylation of alkenes with 7 by a radical chain mechanism.The processes are of preparative value only in cases of alkene substrates which are neither highly polymerizable nor prone to radical attack on allylic substituents.Several highly halogenated compounds prepared by treatment of haloethenes with 6 or 7 are reported.The reaction between 5 and benzaldehyde, to form acetone and 1-benzoyl-2-phenylhydrazine, was found to be second order overall, first order in 5 and first order in benzaldehyde between 0.4 M and neat benzaldehyde.This result does not appear to be compatible with a mechanism involving decomposition of 5 to acetone and phenyldiazene, with subsequent reaction of the latter with benzaldehyde.
Reaction of Substituted Hydrazones with Thionyl Chloride and Sulfuryl Chloride
Meier, Herbert,Trickes, Georg,Laping, Elisabeth,Merkle, Ursula
, p. 183 - 192 (2007/10/02)
Treatment of acetylhydrazones 2, ethoxycarbonylhydrazones 3, p-tolylsulfonylhydrazones 4 or semicarbazones 5 with thionyl chloride leads to the 1,2,3-thiadiazoles 6a-o.Sulfuryl chloride on the other hand accomplishes the transfer of chlorine without incorporating a sulfur atom.The new synthesized 1,2,3-thiadiazoles 6g-o are characterized in detail by spectroscopic methods.
