Synthesis of New 2‐Phenylpyrano[3,2‐b]phenothiazin‐4(6H)‐one Derivatives |
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Authors: | Tanaji N. Bansode Gangadhar A. Meshram |
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Affiliation: | 1. Department of Chemistry, B. N. N. College, Bhiwandi, Thane (M.S.) 421 305, India;2. Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai 400 098, India |
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Abstract: | 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 aromatic 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 ( 5a – 5j ) by refluxing in an acetic acid/HCl mixture. |
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Keywords: | acetyl phenothiazine Baker‐Venkataraman transformation 1,3‐diones pyranones pyranophenothiazine |
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