从[13C 6]-丙酸开始制备B 6组的[13 C 16]标记的维生素(PN,PL和PM)。以十个线性步骤合成了[13 C 18] -PN,总产率为17%。因此,所涉及的酯的更高的烷基同系物对所选合成途径中的中间体的反应结果显示出积极的影响。用高锰酸钾和甲胺将[13C 4] -PN氧化为[13 C 8] -PL,然后酸水解亚胺衍生物。可以通过用钯氢化由[13C 6] -PN的肟衍生物制备[13 C 8] -PM。
The Synthetic Intermediate of Pyridoxine. II. The Thermal Cyclization of Ethyl α-Isocyanopropionate to 5-Ethoxy-4-methyloxazole
作者:Itsutoshi Maeda、Kazushi Togo、Ryonosuke Yoshida
DOI:10.1246/bcsj.44.1407
日期:1971.5
product, II, was 20%; unreacted I (30%), ethyl α-cyanopropionate(20%), and dimer of I (5%) were also obtained. The α-hydrogen of ethyl α-isocyanosuccinate (X) can be more easily removed than that of I, so X may be expected to be more readily converted to 5-ethoxy-4-ethoxycarbonylmethyloxazole (XI), which is also an intermediate of pyridoxine. The yield of XI from X did not exceed 30% because of the
α-异氰基丙酸乙酯 (I) 热环化生成 5-乙氧基-4-甲基恶唑 (II) 作为合成吡哆醇的中间体。也进行了几种新的α-异氰基羧酸烷基酯与相应的5-烷氧基-4-取代的恶唑的类似反应。研究了I的热环化反应产物。180℃环化5小时,主产物II的最大收率为20%;还得到了未反应的 I (30%)、α-氰基丙酸乙酯 (20%) 和 I 的二聚体 (5%)。α-异氰基琥珀酸乙酯 (X) 的 α-氢比 I 更容易去除,因此可以预期 X 更容易转化为 5-乙氧基-4-乙氧基羰基甲基恶唑 (XI),它也是吡哆醇。
Process for the continuous preparation of substituted oxazoles
申请人:——
公开号:US20030050478A1
公开(公告)日:2003-03-13
The present invention relates to a process for the continuous preparation of 5-alkoxy-substituted oxazoles, in particular for the continuous preparation of 4-methyl-5-alkoxy-substituted oxazoles, and to a process for preparing pyridoxine derivatives.
Process for the preparation of substituted oxazoles
申请人:——
公开号:US20030125567A1
公开(公告)日:2003-07-03
The present invention relates to a process for preparing 5-alkoxy-substituted oxazoles, in particular for preparing 4-methyl-5-alkoxy-substituted oxazoles and also a process for preparing pyridoxine derivatives.
The present invention relates to a process for continuously preparing 5-alkoxy-substituted oxazoles, in particular for continuously preparing 4-methyl-5-alkoxy-substituted oxazoles and also a process for preparing pyridoxine derivatives.