- Preparation method of m-phenoxy benzaldehyde
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The invention provides a preparation method of m-phenoxy benzaldehyde, and belongs to the technical field of organic synthesis. The preparation method provided by the invention comprises the following steps: condensing m-cresol serving as a raw material with halogenated benzene to obtain m-phenoxytoluene, reacting the m-phenoxytoluene with chlorine to chloridize methyl to obtain a m-phenoxytoluene chloro product, oxidizing the m-phenoxytoluene chloro product through Komblum to obtain an oxide of the m-phenoxytoluene chloro product, and directly hydrolyzing the m-phenoxytoluene chloro product without separation to obtain the product m-phenoxy benzaldehyde. The preparation method provided by the invention has the advantages that the raw materials are cheap and easily available, the yield is high, the product quality meets the market demand, the problems of high raw material price, many side reactions, many impurities, low yield, large wastewater amount and serious environmental pollution in the traditional process are solved, and the production cost of m-phenoxybenzaldehyde is greatly reduced. Data of the embodiment shows that the total yield of m-phenoxybenzaldehyde obtained by the preparation method provided by the invention is 83.5%, and the gas phase content is 99.3%.
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- Practical Procedures for the Preparation of N-tert-Butyldimethylsilylhydrazones and Their Use in Modified Wolff-Kishner Reductions and in the Synthesis of Vinyl Halides and gem-Dihalides
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In this work we develop practical chemistry for the preparation of N-tert-butyldimethylsilylhydrazone (TBSH) derivatives from carbonyl-containing compounds and show that these products serve as superior alternatives to simple hydrazones in Wolff-Kishner-type reduction reactions, in the Barton vinyl iodide preparation, in the synthesis of vinyl bromides, and in the synthesis of gem-diiodides, gem-dibromides, and gem-dichlorides. In our new procedure for silyl hydrazone synthesis, aliphatic and aromatic ketones and aldehydes are shown to undergo highly efficient coupling (typically >95% yield) to form the corresponding TBSH derivatives when combined with equimolar amounts of 1,2-bis(tert-butyldimethylsilyl)-hydrazine (BTBSH) and a catalytic quantity of scandium trifluoromethanesulfonate (typically, 0.01 mol %), neat, or in solvent. Optimized procedures are provided for the use of TBSH derivatives in a Wolff-Kishner-type reduction protocol that proceeds at low temperature (23-100 °C) and in a single reaction flask. Similarly, protocols for the use of TBSH derivatives as precursors to vinyl halides and gem-dihalides are described in detail.
- Furrow, Michael E.,Myers, Andrew G.
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p. 5436 - 5445
(2007/10/03)
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- Chemical process for preparing 3-phenoxybenzyl chloride
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Reaction of 3-phenoxytoluene with bromine at elevated temperature yields 3-phenoxybenzyl bromide, 3-phenoxybenzal bromide, or a mixture thereof. In contrast to teachings of the prior art, phosphorus halide catalysis or u.v. activation is not required to achieve a desirable amount of side-chain bromination with a minimum of nuclear halogenation. For example, it was observed that at 265±5° C., good yields of the desired benzyl and benzal bromide were obtained, but no nuclear halogenated by-product was detected by gas chromatography. The comparable chlorination is also effective.
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