Synthesis of benzoxazole-2-ones, benzothiazole-2-ones and their 2-thione derivatives : Efficient conversion of 2-thione to 2-oxo derivatives

A highly practical procedure for preparing benzoxazole-2-ones, benzothiazole-2-ones and its 2-thione derivatives using ethylchloroformate and carbon disulfide and the corresponding aminophenols and aminothiophenols as the starting materials in one-pot protocol is presented. The yields vary from good to excellent, the conditions are mild, and the use of toxic and harmful chemicals is avoided. An efficient conversion of benzoxazole-2-thione to 2-one derivative in high yield has also been carried out.