7145-82-6Relevant articles and documents
Dehalogenation of o-dihalogen substituted arenes and α,α′-dihalogen substituted o-xylenes with lanthanum metal
Nishiyama, Yutaka,Kawabata, Hiroshi,Nishino, Toshiki,Hashimoto, Kouji,Sonoda, Noboru
, p. 6609 - 6614 (2007/10/03)
It was found that lanthanum metal caused the dehalogenation of o-dihalogen substituted arenes and α,α′-dihalogen substituted o-xylenes to generate the corresponding benzynes and o-quinodimethanes. When o-dihalogen substituted arenes were allowed to react with lanthanum metal in the presence of dienes, the Diels-Alder products between benzyne and dienes were formed in moderate to good yields. Similarly, the Diels-Alder adducts of o-quinodimethane with dienophiles were obtained, in the reaction of α,α′-dibromo-o-xylenes with lanthanum metal in the presence of dienophiles.
A practical synthesis of an anti-methicillin resistant Staphylococcus aureus cephalosporin BMS-247243
Singh, Janak,Kim, Oak K.,Kissick, Thomas P.,Natalie, Kenneth J.,Zhang, Bo,Crispino, Gerard A.,Springer, Dane M.,Wichtowski, John A.,Zhang, Yunhui,Goodrich, Jason,Ueda, Yasutsugu,Luh, Bing Y.,Burke, Brian D.,Brown, Matthew,Dutka, Anthony P.,Zheng, Bin,Hsieh, Dau-Ming,Humora, Michael J.,North, Jeffrey T.,Pullockaran, Anne J.,Livshits, Juliya,Swaminathan, Shankar,Gao, Zhinong,Schierling, Peter,Ermann, Peter,Perrone, Robert K.,Lai, Mei C.,Gougoutas, Jack Z.,DiMarco, John D.,Bronson, Joanne J.,Heikes, James E.,Grosso, John A.,Kronenthal, David R.,Denzel, Theodor W.,Mueller, Richard H.
, p. 488 - 497 (2013/08/07)
A practical synthesis of the anti-methicillin resistant Staphylococcus aureus cephem (6R-trans)-E-7-[[[[2,5-dichloro-4-[3-[(carboxymethyl)amino]-3-oxo-1-propenyl] phenyl]-thio]-acetyl]amino]-4-[[(2-carboxy-8-oxo-5-thia-1-azabicyclo-[4.2.0]oct- 2-en-3-yl)methyl]thio]-2,6-dimethyl-1-[3-(4-methylmorpholino-4-yl)propyl]-1- pyridinium, hydroxide, inner salt (BMS-247243) was developed. A process was developed for the interchange of the iodide counterion in 3a to chloride 3b that was essential for an efficient synthesis of the C-3 side chain 4-mercaptopyridone 6b. Use of catalytic Bu4NCl in the reaction of chlorocinnamide 14 with the Li-salt of methylthioglycolate formed the methyl ester of the C-7 side chain 12b in high yield. Reaction with the dianion of thioglycolic acid gave an increased level of the corresponding Michael addition byproduct that led to lower quality thermodynamic product 12b by the reverse reaction. Cephem nucleus 16 was acylated with the acid chloride of acid 12b in a biphasic system to circumvent the cumbersome workup involved in reactions mediated by carbodiimdes DCC or EDAC for the synthesis of diester 17. An unusual degradation product diacid 20 was obtained during the deprotection of diester 17 with TFA to amorphous diacid 19. Reaction of diacid 19 with 4-mercaptopyridone 6b formed BMS-247243 in moderate yield. Alternately, an efficient coupling of diester 17 with 4-mercaptopyridone 6b gave crystalline diester 21 with minimal (1%) contamination of the double bond isomer 22. Double deprotection of diester 21 followed by crystallization furnished the double zwitterion BMS-247243 in high yield.
Nucleophilic Displacement in Polyhalogenoaromatic Compounds. Part 11. Kinetics of Protiodeiodination of Iodoarenes in Dimethyl Sulphoxide-Methanol
Bolton, Roger,Moore, Clive,Sandall, John P.B.
, p. 1593 - 1598 (2007/10/02)
The rates of methoxide-ion induced protiodeiodination of a number of polychloroiodobenzenes and their derivatives have been measured in dimethyl sulphoxide-methanol (9:1 v/v; 323.2 K).The true reagent under these conditions appears to be the dimethyl sulphoxide anion, and the rates of reaction in some cases appear to approach that expected of a diffusion controlled process.This corresponds to a major decrease in the efficacy of further activating substituents in the aromatic system, altough deactivating groups such as p-OMe still show large effects.Chlorine promotes protiodeiodination in the order of efficiency o-Cl > m-Cl > p-Cl; the trifluoromethyl group activates displacement in the order o-CF3 > p-CF3 > m-CF3, although with much less difference between isomeric sites. o-Nitro-groups promote protiodeiodination whereas the p-nitro-group encourages methoxydeiodination.No evidence of methoxydeiodination was found in attack of the polychloroiodobenzenes, although the rates of methoxydechlorination of the corresponding polychlorobenzenes suggest that in some cases this might occur.Evidence rejecting the possible SRN1 mechanism and supporting nucleophilic attack by a carbanionic species upon iodine is presented.
Organomercury Compounds. XXV The Mercuration of 1,2,4-Trichlorobenzene
Deacon, Glen B.,Taylor, Brian S. F.
, p. 301 - 312 (2007/10/02)
Mercuration of boiling 1,2,4-trichlorobenzene with mercuric trifluoroacetate yields complex species, which were shown to contain mainly μ-(2,5,6-trichloro-1,3-phenylene)dimercury bridging units and 2,3,6-trichlorophenyl mercury terminal groups by halogenodemercuration reactions, and bis(2,3,6-trichlorophenyl)mercury, which was independently sythesized from 2,3,6-trichlorophenyllithium and mercuric chloride.The organolithium compound was formed regiospecifically on reaction of 1,2,4-trichlorobenzene with butyllithium.Mercuration of 1,2,4-trichlorobenzene with mercuric trifluoroacetate (mole ratio 1 : 1) in trifluoroacetic acid results in regiospecific monomercuration giving 2,4,5-trichlorophenylmercuric trifluoroacetate.This compound undergoes rearrangement in boiling 1,2,4-trichlorobenzene to give a 2,3,6-trichlorophenylmercurial, and is considered to be an intermediate in the mercuration synthesis of bis(2,3,6-trichlorophenyl)mercury.Thus, in 1,2,4-trichlorobenzene, the kinetically and thermodynamically favoured mercuration positions differ by contrast with the reported behaviour of 1,2,3-trichlorobenzene.Formation of the complex mercuration products is considered to involve μ-(2,5,6-trichloro-1,3-phenylene)bis(trifluoroacetato)dimercury and bis(2,3,6-trichlorophenyl)mercury as intermediates.The new mercurials, bis(2,3,5-trichlorophenyl)-, bis(3,4,5-trichlorophenyl)- and bis(2,4-dichlorophenyl)-mercury, have been prepared from the appropriate polychloroanilines by the diazonium route.
