Premium
Directed metalation of pyridinesulphonamides. Synthesis of pyridine‐fused isothiazoles and 1,2‐oxathioles
Author(s) -
Alo Babajide I.,
Familoni Oluwole B.,
Marsais Francis,
Queguiner Guy
Publication year - 1992
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.5570290109
Subject(s) - benzophenone , chemistry , metalation , lithium diisopropylamide , pyridine , lithium (medication) , medicinal chemistry , organic chemistry , ion , medicine , deprotonation , endocrinology
4‐Lithio‐ N‐t ‐butylpyridine‐3‐sulphonamide reacted with benzophenone and carbon dioxide respectively to give the corresponding intermediates which on appropriate treatment gave isothiazolo[5,4‐ c ]pyridin‐3‐one 1,1‐dioxides. Metalation of 2‐ and 4‐( N,N ‐dialkylaminosulphonyl)pyridines with lithium diisopropylamide (LDA) gave anions which reacted with benzophenone to give carbinols which thermally cyclised to 1,2‐oxathiolo[3,4‐b]pyridine and 1,2‐oxathiolo[4,3‐ c ]pyridine respectively.