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An Efficient One‐Step Synthesis of Piperidin‐2‐yl and Pyrrolidin‐2‐yl Flavonoid Alkaloids through Phenolic Mannich Reactions
Author(s) -
Nguyen Thanh Binh,
Wang Qian,
Guéritte Françoise
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201101312
Subject(s) - chemistry , iminium , flavonoid , mannich reaction , regioselectivity , reagent , alkylation , organic chemistry , chrysin , phenols , imine , combinatorial chemistry , catalysis , antioxidant
An efficient one‐step synthesis of piperidin‐2‐yl and pyrrolidin‐2‐yl flavonoid alkaloids was achieved in good to excellent yields by a highly regioselective phenolic Mannich reaction of chrysin with cyclic imines or iminium salts. Performing the reaction in a mixture of H 2 O/THF in the absence of an external reagent afforded the C‐6 alkylated product exclusively. The same reaction in water in the presence of NaOH provided the C‐8 alkylated flavonoid as a major product. The reaction has been successfully extended to simple phenols.