上海
利用過硫酸鉀在堿性條件下氧化苯酚，然后水解，在苯酚對(duì)位引入酚羥基的反應(yīng), 稱為Elbs氧化反應(yīng)。此反應(yīng)也被稱為 Elbs過硫酸鹽氧化反應(yīng)，此反應(yīng)與類似只是底物由苯胺變?yōu)楸椒樱瑱C(jī)理也與其類似。此反應(yīng)最早由Elbs在1893年首先報(bào)道。此反應(yīng)的反應(yīng)位點(diǎn)在酚的對(duì)位，如果對(duì)位有取代基，在鄰位發(fā)生氧化的產(chǎn)率很低，間位不發(fā)生反應(yīng)。有文獻(xiàn)報(bào)道在飽和NaCl或Na2SO4溶液中進(jìn)行反應(yīng)或者利用氮?dú)夤呐莩鹾筮M(jìn)行反應(yīng)可以提高產(chǎn)率【Chem. Rev., 1951, 49, 91；J. Org. Chem., 1984, 49, 645】。
反應(yīng)機(jī)理
對(duì)位反應(yīng)位點(diǎn)的特點(diǎn)是由于苯酚的互變異構(gòu)體決定的，過硫酸鹽的氧原子對(duì)苯酚進(jìn)行親電取代，水解得到產(chǎn)物。
反應(yīng)實(shí)例
【J. Org. Chem., 1984, 49, 645】
【J. Org. Chem., 1988, 53, 5519】
【Journal of Medicinal Chemistry, 2007, 50, 350-355】
【Bioorganic and Medicinal Chemistry, 2009, 17, 3414-3425】
【European Journal of Medicinal Chemistry, 2012, 58, 72-83】
【Macromolecules, 2013, 46, 5520-5530】
2,5-Dihydroxypyridine To 1 (38.0 g, 0.4 mol) and NaOH (80.0 g, 2 mol) in water (1.5 L) at 0℃ was added FeSO4 (2.0 g) in water (20 mL) and K2S2O8 (135.0 g, 0.5 mol). After 20 h at 20 ℃ and filtration, conc H2SO4 was added (cooling) to pH 0.75 and the mixture was heated to 100 ℃ under N2 for 30 min. Cooling, neutralization by 10 N NaOH to pH 6.5, extraction (Soxhlet) with IPA and evaporation afforded 19 g of 2 (42%).
【Behrman EJ, J Am Chem Soc., 1958, 80, 3717】
相關(guān)文獻(xiàn)
1. Elbs, K. J. Prakt. Chem.1893, 48, 179-185.
2. Watson, K. G.; Serban, A. Aust. J. Chem. 1995, 48, 1503-1509.
3. Neumann MS， J Org Chem., 1980, 45, 4275
4. Wallace TW， Synthesis, 1983, 1003
5. Behrman EJ， Beil J Org Chem.,2006, 2, 22
6. Dai, K.; Wen, Q.; Liu, X.; Chen, S. Faming Zhuanli Shenqing CN102408401 (2012).
參考文獻(xiàn)
一、J.J. Li, Name Reactions: A Collection of Detailed Mechanisms and Synthetic Applications, Elbs oxidation，page 76.
二、reactionflash：Elbs oxidation
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