- A boron reagent dimethylamine base boric acidfrequency ester, synthesis and use
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The invention relates to novel boronizing agent dimethylamino boronic acid pinacol ester PinB(DMA) the structure of which is in the specification. The specific synthesis steps are as follows: reacting raw material B(NME2)3 with pinacol for 2-5 hours under the solvent-free condition at the temperature of 50-70 DEG C; and distilling under the vacuum condition of minus 0.1 Mpa, and collecting fraction of 45-50 DEG C, namely the fraction is the product. The PinB(DMA) provided by the invention has the characteristics that water sensitivity is low, structure is stable, ultralow temperature reaction can be avoided when the PinB(DMA) participates in boronization reaction, and the like; and the market value of the PinB(DMA) is important. Compared with the similar processes, the synthesis process of the boronizing agent in the invention has the obvious characteristics of simple reaction steps, mild process condition, no solvent reaction, good process stability and simple post-treatment; and the boronizing agent prepared by the synthesis process is high in yield and good in purity. The boronizing agent is good in purity and has wide application prospect in the boronization reaction.
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- Synthesis of novel halopyridinylboronic acids and esters. Part 2: 2,4, or 5-Halopyridin-3-yl-boronic acids and esters
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This paper describes a general method for the synthesis and the isolation of novel 2,4, or 5-halopyridin-3-yl-boronic acids and esters 4, 7, 10, 13, 15. These compounds are prepared taking into account a regioselective halogen-metal exchange using nBuLi or a regioselective ortho-lithiation using lithium diisopropylamide and subsequent quenching with triisopropylborate starting from appropriate mono or dihalopyridines. All substrates studied to date provided a single regioisomeric boronic acid or ester product. Additionally, these compounds have been found to undergo Pb-catalyzed coupling with a range of arylhalides and authorize a strategy to produce new pyridines libraries.
- Bouillon, Alexandre,Lancelot, Jean-Charles,Collot, Valerie,Bovy, Philippe R.,Rault, Sylvain
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p. 3323 - 3328
(2007/10/03)
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