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Heterocycles from substituted amides II. Novel behavior of a reactive thiophene in some cyelo‐ and acyclo‐addition reactions
Author(s) -
Chupp John P.
Publication year - 1972
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.5570090513
Subject(s) - chemistry , acrylonitrile , dimethyl acetylenedicarboxylate , diethyl azodicarboxylate , thiophene , malononitrile , medicinal chemistry , adduct , michael reaction , organic chemistry , cycloaddition , polymer , copolymer , catalysis , triphenylphosphine
Abstract N,N' ‐Diisopropyl‐ N,N' ‐diphenyl‐2,4‐thiophenediamine ( 1 ) has demonstrated its remarkable electron‐donating abilities and atypical behavior as a thiophene, by its facile reaction with a number of electron deficient dienophiles. Thus, β‐nitrostyrene, ethoxymethylene malononitrile, diethyl azodicarboxylate and dimethyl acetylenedicarboxylate undergo Michael‐type addition at the 5‐position of 1 to form adducts 2, 3, 4 , and 5 . Alternatively, the dienophiles, acrylonitrile, N ‐phenylrnaleimide and phenyl‐1,2,4‐triazoline‐3,5‐dione gave novel cyclic materials 6, 9 , and 11 , not necessarily arising from simple Diels Alder addition. Structure proofs for the products as well as alternative mechanisms for their formation are discussed.