甲基膦酸二乙酯是什么？ 简介 甲基膦酸二乙酯，又称甲基磷酸二乙酯，是一种无色至淡黄色液体有机磷化合物，具有较低的熔点和沸点。它易挥发但不易燃，对光敏感，需避免阳光直射。 甲基膦酸二乙酯的性状 化学性质 甲基膦酸二乙酯的化学性质稳定，但在一定条件下可发生多种化学反应。含磷氧双键和酯基，可与多种亲核试剂反应，如醇、酚、胺等。还可与卤代烃、酰氯等发生取代反应，生成新的有机磷化合物。 用途 在医药领域，甲基膦酸二乙酯常用于合成抗癌药物、抗病毒药物等重要的药物分子。在农药领域可作为杀虫剂、杀菌剂等农药原料。在材料科学领域可用于合成具有特殊结构和性能的高分子材料。 参考文献 [1] Aschmann S M , Tuazon E C , Atkinson R .Atmospheric Chemistry of Diethyl Methylphosphonate, Diethyl Ethylphosphonate, and Triethyl Phosphate[J].Journal of Physical Chemistry A, 2005, 109(10):2282. [2] Xiang H F , Xu H Y , Wang Z Z ,et al.Dimethyl methylphosphonate (DMMP) as an efficient flame retardant additive for the lithium-ion battery electrolytes[J].Journal of Power Sources, 2007, 173(1):562-564. [3] Henderson M A , White J M .ChemInform Abstract: Adsorption and Decomposition of Dimethyl Methylphosphonate on Platinum(111).[J].Cheminform, 1989, 20(4). 查看更多
Pyridinium Hydrobromide Perbromide: A Versatile Brominating Agent？ Pyridinium Hydrobromide Perbromide (PHBP) is a solid complex formed by the reaction of bromine with pyridine hydrobromide salt. It serves as a mild and selective brominating reagent in various reactions. PHBP exhibits high yields and stereo selectivity in α-bromination reactions of ketones and can also facilitate dehydrogenation reactions. Can PHBP be used for α-bromination of ketones? PHBP has been proven to be highly effective in α-bromination reactions of ketones. For example, when PHBP reacts with cyclohexanone in acetic acid, it yields α-bromo-cyclohexanone. Interestingly, in the presence of CuBr2, the yield of the reaction is further improved. Similarly, other ketones such as cyclopentenone can also undergo successful bromination with PHBP in the presence of pyridine. How does PHBP facilitate bromination of aromatic compounds? PHBP is an ideal single brominating agent for activated aromatic ethers and phenols. It selectively mono-brominates aniline, yielding ortho-substituted products with high yields. PHBP has been widely used for the analysis and detection of aniline and phenol. Alternatively, bromine-1,4-dioxane can also be used for bromination of phenols. PHBP can also be employed for multi-bromination reactions. For instance, 2-hydroxy-4-methoxybenzaldehyde treated with PHBP (2.1 eq. pyridine) yields 3,5-dibromo-2-hydroxy-4-methoxybenzaldehyde, while using 3.5 times the amount of PHBP under the same conditions predominantly produces 2,4,6-tribromo-5-methoxyphenol. Can PHBP be used for dehydrogenation/oxidation reactions? PHBP can convert ketones in steroids, tricyclic terpenes, and other polycyclic compounds into phenols. Furthermore, PHBP can be used for the preparation of alkyl bromides from alcohols and for amine transfer nitrosation. Under phase transfer conditions, PHBP can also oxidize thioaldehydes to aldehydes and ketones. Heating PHBP to 230 ℃ yields 3-bromopyridine (37%) and 3,5-dibromopyridine (33%). Indole, imidazole, and benzothiazine can undergo mono-bromination reactions with PHBP at room temperature or low temperatures. Can PHBP catalyze the nitrogenation of alkenes? PHBP, in combination with chloramine-T as a nitrogen source, serves as an effective catalyst for the nitrogenation of alkenes. Both electron-deficient and electron-rich alkenes can undergo this reaction. References 1. Giordano, C.; Coppi, L. J. Org. Chem., 1992, 57, 2765. 2. Reeves, W. P.; King, R. M. Synth. Commun., 1993, 23, 855. 3. Cordoba, R.; Plumet, J. Tetrahedron Lett., 2002, 43, 9303. 4. Meyer, W. L.; Clemans, G. B.; Manning, R. A. J. Org. Chem., 1975, 40, 3686. 5. Alker, D.; Swanson, A. G. Tetrahedron Lett., 1990, 31, 1479. 6. Ali, S. I.; Nikalje, M. D.; Sudalai, A. Org. Lett., 1999, 1, 705. 查看更多
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