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Alternative Methylation for the Synthesis of (+)‐Perophoramidine
Author(s) -
Du Yu,
Wu Haoxing,
Song Hao,
Qin Yong,
Zhang Dan
Publication year - 2012
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.201200295
Subject(s) - chemistry , methylation , amidine , isomerization , tautomer , conformational isomerism , stereochemistry , medicinal chemistry , catalysis , organic chemistry , biochemistry , molecule , gene
An alternative N 1 ‐methylation strategy was reported in the late‐stage of the total synthesis of (+)‐perophoramidine. Preparation of (+)‐perophoramidine was featured by an acid‐catalyzed isomerization of amidine 5 to its CN double bond tautomer 8 , followed by two steps of N 1 ‐methylation with NaHMDS/MeOTf and oxidation with MnO 2 . In contrast, direct methylation of amidine 5 afforded the N 23 ‐methylation conformers 9a and 9b . Further oxidation of 9a and 9b led to N 23 ‐methylated perophoramidine.