| Co-Investigator(Kenkyū-buntansha) |
INOKUCHI Tsutomu Okayama University, Dept. Applied Chem,. Instructor, 工学部, 教務員 (50168473)
OKUMOTO Hiroshi Okayama University, Dept. Applied Chem., Instructor, 大学院・自然科学研究科, 助手 (90183251)
TANAKA Hideo Okayama University, Dept. Applied Chem., Associate Professor, 工学部, 助教授 (60032950)
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| Research Abstract |
A practically viable procedure for the oxidation of 1, 2 ; 5, 6-0-indirect isopropylidene-alpha-D-glucofuranose to the corresponding ulose has been developed by using the indriect electrooxidation method with two redox couples of RuO_4/RuO_2 and [Cl^+]/Cl^-. The conditions were optimized as follows : an aqueous phase at pH ca. 10 ; a mixture of carbon tetrachloride and tert-butyl alcohol (ca. 9 : 1 v/v) as an organic phase ; current densities at 10-40 mA/cm^2 ; temperature at 20-40 ^0 ; the use of 2 mol% of RuO_2.2H_2O. Thus, the electrolysis under the above conditions afforded the desired ulose in 90% yield. The method was successfully applied to a facile synthesis of isopropyl 3-amino-4-cyclohexyl-2-hydroxybutanoate from D-glucose diacetonide with chiral integrity of the C (4), C (5) carbons.
The synthesis of 1, 3-dichloroacetone which is one of the most important synthetic intermediates in the production of N^2-sulfamoyl-3- [[(2-guanidino-4-thiazolyl) methyl] thio] -propionamidine (a
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histamine H_2 recepter) was investigated. The conditions for the indirect electrooxidation of 1, 3-dichloro-2-propanol were optimized in detail by examining various factors. Thus, the electrolysis of 1, 3-dichloro-2-propanol was carried out in an AcOEt-aqueous NaCl (2 : 3 V/V) system buffered at pH 3-4 in a divided cell as 0-5 ^OC, giving the desired ketone in 96% yield and, consequently, hence the formation of 1, 1, 3-trichloroacetone was suppressed to less than 1%. The method has proven to be useful for the oxidation of cyclohexane-1, 4-diol to cyclohexane-1, 4-dione, an important intermediate for electronics material such as TCNQ.
In conclusion, as a result of the present Developmental Scientific Research, the ruthenium mediated indirect electrooxidation method can be extended, in a preparative scale, to the oxidation of a variety of alcohols including halohydrins and carbohydrates through making a proper choice of various factors, in particular, an electrolysis cell, pH value, and electrolysis medium. Less
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