A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- ma...A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- matic carboxylic acids in the presence of phosphorous oxychloride in pyridine. Benzoyloxy esters were converted into their 1,3-diones （4a--4j） by using dry KOH in pyridine via Baker-Venkataraman transformation reaction. The 1,3-diones thus obtained were cyclised to pyranophenothiazines （Sa--Sj） by refluxing in an acetic acid/HCl mixture.展开更多
文摘A new synthesis of 2-phenylpyrano[3,2-b]phenothiazin-4（6H）-one derivatives was reported. First 2,10-diacetyl-3-hydroxyphenothiazine （2） was converted into their benzoyloxy esters （3a--3j） using different aro- matic carboxylic acids in the presence of phosphorous oxychloride in pyridine. Benzoyloxy esters were converted into their 1,3-diones （4a--4j） by using dry KOH in pyridine via Baker-Venkataraman transformation reaction. The 1,3-diones thus obtained were cyclised to pyranophenothiazines （Sa--Sj） by refluxing in an acetic acid/HCl mixture.
