Premium
Synthesis of New 2‐Phenylpyrano[3,2‐ b ]phenothiazin‐4(6 H )‐one Derivatives
Author(s) -
Bansode Tanaji N.,
Meshram Gangadhar A.
Publication year - 2011
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.201100033
Subject(s) - chemistry , pyridine , diacetyl , acetic acid , medicinal chemistry , organic chemistry
Abstract A new synthesis of 2‐phenylpyrano[3,2‐ b ]phenothiazin‐4(6 H )‐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.