- METHOD FOR SYNTHESIZING 3,5-DICHLOROANISOLE FROM 1,3,5-TRICHLOROBENZENE
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The invention relates to a method for synthesizing 3,5-dichloroanisole from 1,3,5-trichlorobenzene, which comprises: a) the reaction between 1,3,5-trichlorobenzene and a methanolate of an alkaline or alkaline-earth metal in a first solvent chosen from among dimethylsulfoxide and 1,1,3,3-tetramethylurea; b) the precipitation of the product resulting from step a) in a second solvent which is not included among substances considered carcinogenic, mutagenic and/or toxic for reproduction by Regulation (EC) n° 1272/2008 of the European Parliament and of the Council of 16 Dec. 2008; then c) the recovery of the precipitate thus obtained. Application: synthesis of 1,3,5-triamino-2,4,6-trinitrobenzene of which 3,5-dichloroanisole is an intermediate product.
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Paragraph 0071; 0072; 0073; 0074; 0075; 0076; 0077; 0078
(2013/07/19)
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- Synthesis of novel structurally simplified estrogen analogues with electron-donating groups in ring A
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A library of 25 novel estrogen analogues were prepared in five to eight steps from mostly commercially available substituted anisoles via bromination, formylation, Corey-Fuchs reaction, elimination, and Sonogashira reaction. Georg Thieme Verlag Stuttgart.
- Tietze, Lutz F.,Vock, Carsten A.,Krimmelbein, Ilga K.,Nacke, Linda
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experimental part
p. 2040 - 2060
(2009/12/27)
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- Meta halogenation of 1,3-disubstituted arenes via iridium-catalyzed arene borylation
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We report the meta halogenation of 1,3-disubstituted arenes to form 3,5-disubstituted aryl bromides and chlorides by using iridium-catalyzed arene borylation chemistry. Iridium-catalyzed borylation of arenes with B2pin2, followed by reaction of the boronic ester with copper(II) bromide or chloride converts arylboronic esters to the corresponding aryl halides. A variety of arenes containing alkoxy, alkyl, halogen, nitrile, ester, amide, and pivaloyl and TIPS-protected alcohols were converted to the corresponding 3,5-disubstituted aryl bromides and chlorides in yields ranging from 46% to 85%. In addition, 2,6-disubstituted and 3-substituted pyridines were converted to the 4-halo and 5-halopyridines, respectively. The utility of this methodology was demonstrated by the formal conversion of nicotine to Altinicline in three steps with an overall yield of 61% using meta bromination of nicotine as the first step. Copyright
- Murphy, Jaclyn M.,Liao, Xuebin,Hartwig, John F.
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p. 15434 - 15435
(2008/09/19)
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- The α-effect in methyl transfers from S-methyldibenzothiophenium fluoroborate to substituted N-methylbenzohydroxamates
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Studies of the α-effect show increased reactivity of nucleophiles having lone pairs of electrons on atoms neighboring the lone pair involved in reactivity when compared to the basicity of the nucleophiles. Hammett-type plots and Broensted-type plots of substituted methylphenyl sulfates vs hydrogen peroxide anions and substituted N-methylbenzohydroxanates (NMBH) with substituted methylarenesulfonates or substituted arenedimethylsulfonium ions have large ρ or βnuc values, indicating a putative tightening of the usual SN2 transition states (anti-Hammond effect). Electrochemical studies of SN2-SET or reactivity indicate that SET character occurs in looser transition states, whereas SN2 transition states are associated with greater tightness. The α-effects for the series of sulfonium salts in completion reactions for 3-ClNMBH anions and 3-nitrophenolate anions are (log kα/knormal) 1.124 for dimethylphenyl sulfonium, 1.512 for dimethyl-1-naphthyl sulfonium, 1.835 for dimethyl-9-anthracenyl sulfonium, and 1.137 for S-methyldibenzylthiophenium. Correlations of the sizes of α-effects with typical SET (or ET) experimental parameters and the inverse dependence of the size of the α-effect on electron demand indicate inclusion of SET character in these SN2 transition states, vs no (or at least diminished) SET character in normal transition states. This dichotomy of tighter SN2 transition states, but looser SET transition states indicated in the α-effect, is examined in the present work.
- Fountain,Felkerson, Cassie J.,Driskell, Jeremy D.,Lamp, Brian D.
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p. 1810 - 1814
(2007/10/03)
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- Total synthesis of (+)- and (-)-neopyrrolomycins, chlorinated phenylpyrrole antibiotics
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The first total synthesis of (+)- and (-)-neopyrrolomycins (11a and 11b) is detailed based on regioselective chlorinations of 3,5-dichloroanisole (2) and 1-(2,3,4-trichloro-6-methoxyphenyl)-1H-pyrrole-2-carboxylic acid (8) with isocyanuric trichloride, followed by optical resolution of racemic neopyrrolomycin (11) with N-(p-tolylsulfonyl)-L-phenylalanyl chloride. Several analogs (21-25) have been prepared from the intermediates, and the structure-activity relationships are also discussed.
- Tatsuta,Itoh
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p. 1449 - 1455
(2007/10/02)
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- Correlation of Reaction Rates with a Substituent Constant Scale Derived from Calculated Electron Densities for a Computer Control Algorithm
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A new ? substituent scale based on electron density calculations by the AM1 quantum mechanical model has been established and used to correlate rates of O-methylation of substituted phenols, as part of a chemical artificial intelligence to control a fully automated apparatus for methyl iodide labeling.
- Cork, David G.,Hayashi, Nobuyoshi
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p. 1583 - 1585
(2007/10/02)
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- Total Synthesis of Chlorinated Phenylpyrrole Antibiotics, (+)- and (-)-Neopyrrolomycins
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(+)- and (-)-Neopyrrolomycins have been synthesized from 3,5-dichlorophenol through regioselective halogenations and optical resolution.
- Tatsuta, Kuniaki,Itoh, Manabu
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p. 8443 - 8444
(2007/10/02)
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- THE REACTIONS OF UNACTIVATED ARYL HALIDES WITH SODIUM METHOXIDE IN HMPA; SYNTHESIS OF PHENOLS, ANISOLES, AND METHOXYPHENOLS
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Sodium methoxide reacts with dichlorobenzenes in HMPA to give the chloroanisoles as a result of a SNAr process.Excess MeONa then effects the demethylation of the ethers to give the chlorophenols via an SN2 reaction.With tri- and tetrachlorobenzenes the initially formed chloroanisoles can be dealkylated to chlorophenols or can suffer further substitution to give the chlorodimethoxybenzenes; these react with excess MeONa to give the chloromethoxyphenols.The results obtained with the various isomers of the di-, tri-, and tetrachlorobenzenes are presented and discussed on the basis of the electronic effects of the substituents.
- Testaferri, L.,Tiecco, M.,Tingoli, M.,Chianelli, D.,Montanucci, M.
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p. 193 - 198
(2007/10/02)
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- Nucleophilic Displacement in Polyhalogenoaromatic Compounds. Part 11. Kinetics of Protiodeiodination of Iodoarenes in Dimethyl Sulphoxide-Methanol
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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.
- Bolton, Roger,Moore, Clive,Sandall, John P.B.
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p. 1593 - 1598
(2007/10/02)
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