- PROCESS FOR PRODUCING 1,2-DIALKOXY-3-FLUOROBENZENE
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The present invention relates to a process for producing a 2-fluoro-6-halophenol as an intermediate; a process for producing a 2-alkoxy-3-fluorophenol and further a 1,2-dialkoxy-3-fluorobenzene from the 2-fluoro-6-halophenol; a second process for producing a 1,2-dialkoxy-3-fluorobenzene from the 2-fluoro-6-halophenol; and a 2-alkoxy-3-fluorophenol. The 2-fluoro-6-halophenol can be obtained using a 2-fluorophenol as a starting material and through a sulfonation reaction, a halogenation reaction, and a deprotection reaction. The 2-fluoro-6-halophenol is alkyl-etherified, and subsequently the halogen atom is converted into a hydroxyl group to obtain the 2-alkoxy-3-fluorophenol, which is further alkyl-etherified to thereby obtain the 1,2-dialkoxy-3-fluorobenzene. Alternatively, a 1,2-dialkoxy-3-fluorobenzene is also obtained by converting the halogen atom of the 2-fluoro-6-halophenol into a hydroxyl group to thereby form 3-fluorocatechol and subsequently alkyl-etherifying two hydroxyl groups thereof. The processes of the invention realize low production costs and high process yields, and thus are suitable for industrial production of a 1,2-dialkoxy-3-fluorobenzene.
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Page/Page column 7-8
(2009/06/27)
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- Synthesis of halogenated phenols by directed ortho-lithiation and ipso-iododesilylation reactions of O-aryl N-isopropylcarbamates
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The regioselective synthesis of halogenated phenols via directed ortho-lithiation reactions of in situ N-silylated O-aryl N-isopropylcarbamates is reported. This protocol is complemented by ipso-iododesilylation reactions of C-silylated carbamates and iodine-magnesium exchange reactions, which are facilitated by the adjacent carbamoyl group. These methods provide an entry into a series of o-fluoro-, o-iodo-, and o,o′-diiodophenols in high yields which are otherwise difficult to obtain. Georg Thieme Verlag Stuttgart.
- Kauch, Matthias,Hoppe, Dieter
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p. 1578 - 1589
(2007/10/03)
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- Halogen-lithium exchange between substituted dihalobenzenes and butyllithium: Application to the regioselective synthesis of functionalized bromobenzaldehydes
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Halogen-lithium interconversion reactions between unsymmetrically substituted mono- and bifunctional dihalobenzenes C6H 3XHal2 and C6H2XYHal2 (Hal=Br, I; X, Y=F, OR, CF3, CH(OMe)2) and butyllithium were investigated. The resultant organolithium intermediates were converted into the corresponding benzaldehydes in moderate to good yields. As a rule, bromine atoms in the position ortho to the functional group were replaced preferentially with lithium. Intramolecular competition experiments with bifunctional systems revealed that fluorine is capable of activating the neighboring bromine atom more strongly than methoxy and dimethoxymethyl groups. On the replacement of the non-activated bromine with iodine a complete reversal of this reactivity pattern can be accomplished due to the preferred iodine-lithium exchange.
- Da?browski, Marek,Kubicka, Joanna,Luliński, Sergiusz,Serwatowski, Janusz
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p. 6590 - 6595
(2007/10/03)
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