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Synthese von bromosubstituierten Butenoliden II
Author(s) -
Martin Roger,
Chapleo Christopher B.,
Svanholt Karen L.,
Dreiding André S.
Publication year - 1976
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19760590811
Subject(s) - chemistry , hydrobromic acid , butenolide , potassium hydroxide , methyl iodide , halogenation , sodium hydroxide , aqueous solution , sodium iodide , organic chemistry , medicinal chemistry
Synthesis of Bromosubstituted Butenolides II . Methyl 4,4′‐dibromosenecioate ( 2 ) was prepared by double N‐bromosuccinimide bromination of methyl senecioate ( 1 ) and converted to methyl 4,4′‐diiodo‐senecioate ( 3 ) with sodium iodide and to 3‐bromomethyl‐2‐buten‐4‐olide ( 4 ) with aqueous hydrobromic acid. A mixture of methyl ( Z )‐ and ( E )‐4‐bromosenecioate ( 8 and 9 ) yielded 3‐methyl‐2‐butenolide ( 5 ) with aqueous hydrobromic acid and a mixture of ( Z )‐and ( E )‐4‐methoxy‐senecioic acid ( 10 and 11 ) with methanolic potassium hydroxide. N‐Bromosuccinimide treatment of the butenolide 5 afforded 4‐bromo‐3‐methyl‐2‐buten‐4‐olide ( 6 ) and 4,4‐dibromo‐3‐methyl‐2‐buten‐4‐olide ( 7 ).