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Synthesis and structural characterisation of 4 H ‐1,3‐benzothiazine derivatives
Author(s) -
Fodor Lajos,
Bernáth Gábor,
Sinkkonen Jari,
Pihlaja Kalevi
Publication year - 2002
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570390512
Subject(s) - chemistry , benzothiazine , potassium permanganate , ring (chemistry) , derivative (finance) , medicinal chemistry , aryl , potassium , stereochemistry , organic chemistry , alkyl , financial economics , economics
The ring‐closure reactions of N ‐arylthiomethylaroylamide derivatives ( 1a‐g ) in the presence of phospho ‐rus oxychloride gave 2‐aryl‐4 H ‐1,3‐benzo‐thiazines (2a‐g). 2‐(3‐Chlorophenyl)‐6‐methyl‐4 H ‐1,3‐benzoth‐iazine ( 2b ) was reduced with Zn to obtain the corresponding 2,3‐dihydro derivative ( 3b ). Potassium permanganate oxidation of 2‐(4‐chlorophenyl)‐2,3‐diethoxy‐4 H ‐ ( 2e ) and 2‐(2‐fluorophenyl)‐6,7‐diefhoxy‐4 H ‐1,3‐benzo‐thiazines ( 2g ) gave the corresponding 4‐ones ( 4e,g ). The reactions of 2‐(4‐chlorophenyl)‐6‐mefhyl‐4 H ‐1,3‐benzofhiazine ( 2c ) with substituted acetyl chlorides led to linearly condensed ß‐lactams ( 5a,b ). The structures of the compounds studied were confirmed by 1 H and 13 C NMR and by their characteristic mass spectrometric fragmentations.