Alternate Name: PDC.
Physical Data: mp 152–153 °C
Solubility: sol DMF, DMSO, acetonitrile; sparingly sol dichloromethane, chloroform, acetone; insol hexane, ether, ethyl acetate.
Handling, Storage, and Precautions: the dry solid can be stored in contact with air. Reaction solvents must be anhydrous and free of reducing impurities. Pyridinium dichromate is reported to be a cancer suspect agent. The reagent should be used in a fume hood.
Preparation of Pyridinium Dichromate：
The reagent was prepared by dissolving 25.0 g (0.25 mol) of CrO3 in 50 mL of distilled H20 and adding 20 mL (0.25 mol) of pyridine dropwise at 0℃. The color of the solution changed from deep purple to bright orange, and the product precipitated as a bright orange solid. The solution was further diluted with 100 mL of acetone, cooled to -30℃ and allowed to stand for 30 min. The precipitate was filtered, washed with acetone, and dried under vacuum to obtain 40.0g (88% yield) of pyridinium dichromate (mp 144-146 ℃)，
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Alternate Name: PDC.
Physical Data: mp 152–153 °C
Solubility: sol DMF, DMSO, acetonitrile; sparingly sol dichloromethane, chloroform, acetone; insol hexane, ether, ethyl acetate.
Handling, Storage, and Precautions: the dry solid can be stored in contact with air. Reaction solvents must be anhydrous and free of reducing impurities. Pyridinium dichromate is reported to be a cancer suspect agent. The reagent should be used in a fume hood.
Preparation of Pyridinium Dichromate：
The reagent was prepared by dissolving 25.0 g (0.25 mol) of CrO3 in 50 mL of distilled H20 and adding 20 mL (0.25 mol) of pyridine dropwise at 0℃. The color of the solution changed from deep purple to bright orange, and the product precipitated as a bright orange solid. The solution was further diluted with 100 mL of acetone, cooled to -30℃ and allowed to stand for 30 min. The precipitate was filtered, washed with acetone, and dried under vacuum to obtain 40.0g (88% yield) of pyridinium dichromate (mp 144-146 ℃)，
这玩意不好用啊，强烈致癌物啊。我宁愿麻烦点做Dess－Martin 试剂
我做的很简单,不用英语写吧:
用大烧杯,100克 CrO3 溶解于100毫升的水中(我用的是自来水).冰浴冷却,向其中慢慢加入81毫升的吡啶(大约10分钟加完).加完后搅拌10分钟. 然后加入300毫升的丙酮,再在零度下搅拌10分钟.
然后我比较懒,一般把烧杯口一封,就放在冰箱里(-10度以下),放一晚上,第二天抽滤,固体用冷的丙酮冲洗.
真空干燥,收率能到接近90%.
我很喜欢用PDC,能用的反应尽量用.哪怕收率比Swern,Dess-Martin稍微低一点点. 因为PDC氧化的操作,后处理太简单了.很多情况下产物不需纯化就可进行下一步反应.
PDC用量一般是多少啊？反应是否完全能否直观的看出来？谢谢！