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Traceless Synthesis of Hydantoin by Focused Microwave irradiation

合成化学 2004年第Z1期12卷 17-17页

作者： Lee Ming-juan SUN Chung-ming Chemistry Department National Dong Hwa University Hualien 974 Taiwan Chemistry Department National Dong Hwa University Hualien 974 Taiwan

Hydantoin analogs have shown versatile therapeutic applications and some of them have been approved by FDA as drugs. For example, Fosphenytoin as a sodium channel antagonist is used for the treatment of epilepsy. Phenytoin has antiarrhythmic, anticonvulsant and antineuralgic activities. Ethotoin and Mephenytoin both show anticonvulsant effect. Nilutamide is a non-steroidal orally-active antiandrogen in combination with surgical castration for the treatment of stage D2 metastatic prostate cancer. (Figure 1)An efficient, microwave-assisted method for the liquid-phase combinatorial synthesis of hydantoins is presented. Nucleophilic substitution of poly (ethylene glycol) immobilized chloroacetyl group with several primary amines is carried out in dichloromethane under microwave cavity. After introduction of various isocyanates, the cyclization/ cleavage step can be performed in mild basic condition by microwave flash heating. Compared to conventional thermal hearting,microwave irradiation decreased the reaction time on the support from several hours to several minutes. The coupling of microwave technology with liquid phase combinatorial synthesis constitutes a novel and attractive avenue for the rapid generation of structurally diverse libraries in good yield and high purity.

关键词： Microwave irradiation, combinatorial synthesis, hyantoin.

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Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu_4FeAlCO_3

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Science China Chemistry 2005年第6期48卷 530-537页

作者： CHEN Chunxia1,2, XU Chenghua1, FENG Liangrong1, SUO Jishuan1 & QIU Fali1 1. Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China Chengdu Institute of Organic Chemistry Chinese Academy of Sciences Chengdu 610041 China

The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hy-droxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2O2 1/2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 120 min, 10 mL distilled water as solvent. Moreover, a kinetic equation of v = k[La ? Cu 4 FeAlCO 3 ][C 6 H 5 OH][H 2 O 2]. and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is pro-posed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

关键词： rare earth, hydrotalcite, microwave irradiation, phenol hydroxylation, kinetics, reaction mechanism.

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