Exhibiting a wide spectrum of practical applications, benzo[d]oxazol-2(3H)-ones (BOA) are considered as key intermediates in the synthesis of pharmaceutical products, organic dyes, and OLED materials among others. Herein, we propose an environmentally benign protocol for the selective mono-halogenation of benzo[d]oxazol-2(3H)-ones. Several chloro- and bromo-substituted BOA derivatives were prepared within less than an hour with high to excellent yields (75%–93%) via this novel, green, and energy sufficient method. This rapid and highly reproducible synthetic approach employs inexpensive commercially available urea-hydrogen peroxide complex and hydrochloric or hydrobromic acid. Simple operations and precise control over the oxidative halogenation, with water being the major by-product of the reaction outcome, are among the strong point of current facile method from the perspective of green chemistry.

中文翻译：

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苯并[d]OXAZOL-2(3H)-ONES选择性单氯化和单溴化的简便且环境友好的合成方法

苯并[ d ]恶唑-2(3 H )-酮 (BOA)具有广泛的实际应用，被认为是医药产品、有机染料和 OLED 材料等合成中的关键中间体。在此，我们提出了一种用于苯并[ d ]恶唑-2(3 H )选择性单卤化的环境友好方案）-那些。通过这种新颖、绿色和能源充足的方法，可以在不到一个小时的时间内以高至优异的产率 (75%–93%) 制备了几种氯代和溴代 BOA 衍生物。这种快速且高度可重复的合成方法采用廉价的市售尿素-过氧化氢复合物和盐酸或氢溴酸。从绿色化学的角度来看，简单的操作和对氧化卤化的精确控制（水是反应产物的主要副产物）是当前简便方法的强项之一。