626-02-8Relevant articles and documents
Tetrafluoropyridyl (TFP): a general phenol protecting group readily cleaved under mild conditions
Brittain, William D. G.,Cobb, Steven L.
supporting information, p. 2110 - 2115 (2019/02/27)
Phenols are extremely valuable building blocks in the areas of pharmaceuticals, natural products, materials and catalysts. In order to carry out modifications on phenols, the phenolic oxygen is routinely protected to prevent unwanted side reactions. Presently many of the protecting groups available can require harsh conditions, specialist equipment, expensive or air/moisture-sensitive reagents to install and remove. Here we introduce the use of the tetrafluoropyridyl (TFP) group as a general protecting group for phenols. TFP can be installed in one step with no sensitivity to water or air, and it is stable under a range of commonly employed reaction conditions including acid and base. The TFP protecting group is readily cleaved under mild conditions with quantitative conversion to the parent phenol, observed in many cases in less than 1 hour.
Method for continuous flow synthesis of phenol-based compound
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Paragraph 0053; 0054, (2017/07/21)
The present invention provides a method for continuous flow synthesis of a phenol-based compound represented by a formula (III), wherein the method is performed in two static mixers, a tubular reactor and an oil-water separator, wherein the two static mixers, the tubular reactor and the oil-water separator are sequentially connected in series. The method comprises that an acid solution and an aniline compound represented by a formula (I) are pumped into the static mixer A; the mixture of the acid solution and the compound represented by the formula (I) flows out from the static mixer A and flows into the static mixer B connected to the static mixer A; a sodium nitrite solution is pumped into the static mixer B, and a reaction is performed to produce a diazonium salt solution represented by a formula (II); and the solution represented by the formula (II) flows out from the static mixer B, is pumped into the tubular reactor connected to the static mixer B, and then into the oil-water separator connected to the tubular reactor, and the water phase is separated to obtain the compound represented by the formula (III). According to the present invention, the method has characteristics of short reaction time, solvent saving and high yield, and can well solve the problems in the synthesis of the phenol-based compound through diazotization hydrolysis in the intermittent kettle type reactor. The formulas (I), (II) and (III) are defined in the specification.
Continuous-flow hydroxylation of aryl iodides promoted by copper tubing
Cyr, Patrick,Charette, André B.
supporting information, p. 1409 - 1412 (2014/06/23)
A simple and ligand-free synthesis of phenols from the corresponding aryl iodides in a continuous-flow system is described. The reaction is complete in only 4 to 20 minutes when heated between 150 to 165 °C in a reactor consisting of a commercially available copper coil. An example of trapping of the phenoxide in situ is also shown.
