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Tetrabutylphosphonium dichromate (TBPDC) has been found an efficient oxidizing agent for the aromatization of various 1,4‐dihydropyridines to their pyridine derivatives in refluxing acetonitrile and also under microwave irradiation. Short reaction times and clean workup are the advantages of this method. 相似文献
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Nuclear monobromination of aromatic ethers can be achieved with a NaClO2/NaBr/Mn(acac)3 catalyst/silica gel system in dichloromethane in regioselective and high-yielding manner under mild conditions. 相似文献
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Matthias?WeilEmail author Berthold?St?ger Erich?Zobetz Enrique J.?Baran 《Monatshefte für Chemie / Chemical Monthly》2006,137(8):987-996
Summary. Dark-red single crystals of HgCr2O7 were grown by reacting HgO and CrO3 in excess at 200°C for four days. The crystal structure (space group P32, Z = 3, a = 7.2389(10), c = 9.461(2) ?, 1363 structure factors, 57 parameters, R[F
2>2σ(F
2)] = 0.0369, wR(F
2 all) = 0.0693) was determined from a crystal twinned by merohedry according to (110). It consists of nearly linear HgO2 units (
(Hg–O) = 2.02 ?) and dichromate units that are linked into infinite chains ‘O3Cr–O–CrO3–Hg–O3Cr–O–CrO3’ running parallel to the c-axis. Six additional Hg–O contacts between 2.73 and 2.96 ? stabilise the structural arrangement. The dichromate anion exhibits
a staggered conformation with a bent Cr–O–Cr bridging angle of 140.7(6)°. Upon heating above 300°C, HgCr2O7 decomposes in a two-step mechanism to Cr2O3. The title compound was additionally characterised by vibrational spectroscopy. 相似文献
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