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A Rapid, Solvent‐Free Phase‐Transfer Catalysis Procedure for N ‐Alkylation of Dihydropyridones and Construction of the Indolizidine, Quinolizidine and Pyridoazepine Structures
Author(s) -
Chou ShangShing P.,
Liu ChihFen
Publication year - 2010
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201000113
Subject(s) - chemistry , quinolizidine , indolizidine , alkylation , bromide , catalysis , acetone , solvent , medicinal chemistry , phase (matter) , organic chemistry , alkaloid
We have developed a solvent‐free phase‐transfer catalysis (PTC) method for the N ‐alkylation of sulfur‐substituted dihydropyridone 4a to give products 5 with varying side‐chains and functional groups. Treatment of the chlorides 5a and 5c with NaI in acetone at reflux gave high yields of the iodides 6a and 6b . The reaction of iodides 7a and 7b with t ‐BuLi at low temperature, followed by sequential treatment with HOAc and NaBH 4 , resulted in the formation of quinolizidine 8a and pyridoazepine 8b , respectively. Similar reaction of bromide 5j with t ‐BuLi gave indolizidine 11 .