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Some 2‐(dialkylamino) substituted chromenylium salts
Author(s) -
Mazzei M.,
Ermili A.,
Sottofattori E.,
Roma G.
Publication year - 1981
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.5570180502
Subject(s) - chemistry , acetic anhydride , sulfuric acid , hydrolysis , hydrochloric acid , malononitrile , organic chemistry , acetic acid , medicinal chemistry , catalysis
The reaction of 2‐(dialkylamino)‐7‐methoxychromones with malononitrile in the presence of acetic anhydride afforded [2‐(dialkylamino)‐7‐methoxy‐4 H ‐chromen‐4‐ylidene]malononitriles. When these compounds were refluxed with concentrated hydrochloric (or hydroiodic) acid, 2‐(dialkylamino)‐7‐methoxy(or hydroxy)‐4‐methylchromenylium salts were obtained. The use of concentrated sulfuric acid or polyphosphoric acid in the hydrolysis was also investigated. The preparation of ethyl [2‐(dialkylamino)‐7‐methoxy‐4 H ‐chromen‐4‐ylidene]cyanoacetates and their behavior when treated with acids are also described, as well as the synthesis of some 3‐(dialkylamino)‐1‐methylnaphtho[2,1‐ b ]pyrylium salts.