PURPOSE: To prepare the titled substance useful as a raw material of various synthetic chemicals such as 1,4-benzodiazepin for mild tranquillizer, by a widely applicable inexpensive method, by using an easily available 3-hydroxy-2-indolinone as a raw material, and oxidizing the material.
CONSTITUTION: The objective compound of formula II (R is H, halogen, alkyl, etc.; R2 is alkyl or aryl) can be prepared by oxidizing 3-hydroxy-2-indolinone of formula I with air using e.g. a copper salt-amine catalyst, preferably in a solvent such as dioxane, at room temperature W170°C, especially at 110W130°C. The copper salt is e.g. cuprous chloride, and the amine is e.g. 1,8-diazabicycloundecene. As an alternative method, the starting compound is oxidized with hydrogen peroxide under alkaline condition using a copper salt catalyst. The reaction is carried out in a 3W10% aqueous solution of e.g. sodium hydroxide at 0W50°C.
SHIBATA YOSHIKO
KONDOU SEI
