A process for preparing 6-hydroxy-3,4-dihydroquinolinone by intramolecular Friedel-Crafts alkylation of N-(4-methoxyphenyl)-3-chloropropionamide in which an equivalent of N-(4-methoxyphenyl)-3-chloropropionamide is contacted with a Lewis acid in DMSO or a high boiling amide or amine at an elevated temperature of from about 150 °C to about 220 °C is provided. The process produces 6-HQ in high yield and a high state of purity such that it may be used in subsequent reactions toward the preparation of cilostazol without intermediate purification. A process for preparing cilostazol from 6-hydroxy-3,4-dihydroquinolinone prepared by the process and improved processes for preparing N-(4-methoxyphenyl)-3-chloropropionamide are also provided.
提供一种制备6-羟基-3,4-二氢
喹啉酮的方法,该方法通过N-(4-
甲氧基苯基)-3-
氯丙酰胺的分子内Friedel-Crafts烷基化反应,其中等量的N-(4-
甲氧基苯基)-3-
氯丙酰胺在
DMSO或高沸点酰胺或胺的高温条件下(约150℃至220℃)与
路易斯酸接触。该方法产生高产率和高纯度的6-HQ,可以在不经过中间纯化的情况下用于制备cilostazol的后续反应。此外,还提供了一种从该方法制备的6-羟基-3,4-二氢
喹啉酮制备cilostazol的方法和改进的制备N-(4-
甲氧基苯基)-3-
氯丙酰胺的方法。