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Lophenol, cholest-4α-methyl-7-en-3β-ol (1), obtained from Dracaena cochinchinensis (Lour.) S. C. Chen, was structurally modified. It was acetylated to protect 3β-hydroxyl group, and then oxidised by selenium dioxide in acetic acid to give cholest-4a-methyl-8-en-3β, Ta-diol diacetate (3). This compound 3 is unstable in chloroform solution or when heated and easily converted to a diene compound, cholest-4a-methyl-7,14-dien-3β-ol acetate (4). The structures of 3 and 4 were elucidated by means of IR, ^1H NMR, ^13C NMR and MS, and the absolute configuration of 3 was established by X-ray crystallography. The property of 3 was also discussed in this paper. Both 3 and 4 are new compounds and were reported for the first time. 相似文献
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光度法测定铜的显色剂虽然很多,但是选择性好,能在水溶液中直接进行测定的试剂却很少。从铜(Ⅱ)的化学性质来考虑,邻,邻’-二氨基偶氮苯(简称DAAB)可能是光度法测定铜(Ⅱ)的良好显色剂。本文对DAAB的合成方法作了改进,用改进过的方法合成了DAAB;并对Cu(Ⅱ)-DAAB-SDBS-Triton X-100新显色体系作了系统的研究,得到了令人满意的结果。 1.试剂和仪器: DAAB(作者合成):0.04%乙醇溶液。铜标准溶液:将高纯金属铜溶于硝酸,加盐酸除尽硝酸。配成浓度为50μg/ml。 相似文献
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本文对邻,邻′-二氨基偶氮苯(DAAB)的合成方法进行了改进,用改进过的方法合成DAAB简便、快速、产率较高、产品稳定、价廉。并对Cu(Ⅲ)-DAAB-SDBS-TritonX-100新显色体系作了系统的研究。在pH4到6的醋酸盐缓冲溶液中,在十二烷基苯磺酸钠(SDBS)和TritonX-100存在下,Cu(Ⅱ)与DAAB形成红色络合物。Cu(Ⅱ)-DAABSDBS-TritonX-100四元体系在530nm处摩尔吸光系数为1.0×10~4 1.mol~(-1)·cm~(-1)。铜量在0.20—5.6ppm范围内服从比耳定律,本体系选择性好。它是分光光度法测定铜的良好的新显色体系。 相似文献