90282-99-8Relevant articles and documents
Halogenated volatiles from the fungus Geniculosporium and the actinomycete Streptomyces chartreusis
Wang, Tao,Rabe, Patrick,Citron, Christian A.,Dickschat, Jeroen S.
supporting information, p. 2767 - 2777 (2014/01/06)
Two unidentified chlorinated volatiles X and Y were detected in headspace extracts of the fungus Geniculosporium. Their mass spectra pointed to the structures of a chlorodimethoxybenzene for X and a dichlorodimethoxybenzene for Y. The mass spectra of some constitutional isomers for X and Y were included in our databases and proved to be very similar, thus preventing a full structural assignment. For unambiguous structure elucidation all possible constitutional isomers for X and Y were obtained by synthesis or from commercial suppliers. Comparison of mass spectra and GC retention times rigorously established the structures of the two chlorinated volatiles. Chlorinated volatiles are not very widespread, but brominated or even iodinated volatiles are even more rare. Surprisingly, headspace extracts from Streptomyces chartreusis contained methyl 2-iodobenzoate, a new natural product that adds to the small family of iodinated natural products.
Synthesis of chlorinated and non-chlorinated biphenyl-2,3- and 3,4-catechols and their [2H3]-isotopomers
Lin, Po-Hsiung,Sangaiah,Ranasinghe, Asoka,Ball, Louise M.,Swenberg, James A.,Gold, Avram
, p. 2624 - 2629 (2007/10/03)
A synthetic scheme is described for chlorinated biphenyl-2,3- and 3,4-catechols to be used as standards for structural assignment of metabolites and protein adducts of 2,2′,5,5′-tetrachlorobiphenyl in which both rings retain chlorine substituents. The scheme has general applicability to the synthesis of chlorinated biphenyl catechols. Dimethyl catechol ethers are coupled to dichloroaniline via the Cadogan reaction to give a library of isomers, followed by demethylation of the ethers with BBr3 to yield the target catechols. Separation of pure isomers is accomplished by TLC or HPLC prior to or following demethylation, depending on the isomer mixture. [ 2H3]-Isotopomers are generated using 2,5-dichloroaniline- d3 as the starting arylamine in the coupling reaction. The dichloroaniline-d3 hydrochloride is obtained as the sole product from nitration of p-dichlorobenzene-d4 followed by Pd/C-catalyzed hydrogenation under strongly acidic conditions. This hydrogenation procedure provides a simple and convenient approach to selective reduction of aryl nitro groups in the presence of halogen ring substituents.
13C and 17O NMR Study of Methoxy Groups in Chlorinated Di- and Trimethoxybenzenes
Knuutinen, J.,Kolehmainen, E.
, p. 315 - 317 (2007/10/02)
13C and 17O NMR data for the methoxy groups in isomeric 1,2-, 1,3- and 1,4-dimethoxybenzenes, 1,2,3-trimethoxybenzenes and most of their chlorinated derivatives and some related brominated compounds were measured for CDCl3 solutions.The 17O NMR chemical shifts show up to 60 ppm dispersion.Comparison between the compounds with and without adjacent chlorine atoms (2,6-di- and 2,4,6-trisubstitution) also showed a clear methoxy carbon chemical shift change.The number and position of the chlorine atoms in the aromatic ring give small but observable effects on the 17O NMR chemical shifts of the methoxy group if it is coplanar with the aromatic plane.Similarly, the degree and nature of the substitution have a minor effect (about 1 Hz) on the 1J(CH) direct coupling values.
Mass Spectra of Chlorinated Veratroles (1,2-dimethoxybenzenes)
Knuutinen, J.,Korhonen, I. O. O.
, p. 70 - 74 (2007/10/02)
The behaviour of all nine chlorinated veratroles (1,2-dimethoxybenzenes) under electron impact has been investigated.The most common fragmentation processes are interpreted using metastable ion analysis and deuterium labelled compounds.For all compounds studied, the most common fragmentation route seems to be the primary loss of a methyl radical followed by loss of carbon monoxide.The ion formed has a well-known quinonoid structure and fragments by several routes elucidated by metastable ion analysis.In general, the spectra of the positional isomers are shown to be practically similar and it is apparent the e.g. the 3- and 4-chloro isomers can be differentiated only from the abundance ratio of the +. and + ions.
