An improved process for the manufacture of Clopidogrel starting from 2-(2-thienyl) ethylamine, which eliminates the isolation of an unstable intermediate like 2-(2-thienyl) ethyl formimine by subjecting it to a one pot cyclization to get 4,5,6,7-tetrahydrothieno (3,2-c) pyridine of Formula II and further reacting with halo-compound of Formula III (where X is Cl or Br) at 20 to 90 °C temperature characterized in a solvent like water and/or dichloroethane in presence of organic or inorganic bases is disclosed herein. This invention further discloses a process for resolution of racemic clopidogrel into its optical antipodes and converting the dextroclopidogrel base into its known polymorphs namely 'Form I' or 'Form II' in solvents selected from methyl propyl ketone, methyl isopropyl ketone, diethyl ketone or their mixture thereof, mixture of ethyl acetate and methyl propyl ketone, mixture of ethyl acetate and methyl isopropyl ketone, or mixture of ethyl acetate and diethyl ketone or ethyl acetate.
一种改进的克洛匹地尔制备工艺,从2-(2-
噻吩基)
乙胺出发,通过将其经过一锅环化反应,消除了类似2-(2-
噻吩基)乙酰
甲醛这样的不稳定中间体的分离,得到化合物4,5,6,7-
四氢噻吩(3,2-c)
吡啶(式II),然后在20至90°C温度下与卤代化合物(式III,其中X为Cl或Br)在
水和/或
二氯乙烷等溶剂中存在有机或
无机碱的情况下进一步反应。该发明还揭示了一种将混合克洛匹地尔分离成其光学对映体并将右旋克洛匹地尔碱转化为其已知的多晶型(即“I型”或“II型”)的工艺,所选溶剂包括丙基甲基酮、异丙基甲基酮、乙酮或它们的混合物、
乙酸乙酯和丙基甲基酮的混合物、
乙酸乙酯和异丙基甲基酮的混合物,或
乙酸乙酯和乙酮的混合物。