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Mannich Reaction with Enaminones: Convenient Synthesis of Functionalized Tetrahydro‐pyrimidines, Dihydro‐1,3‐oxazines, and Dihydro‐1,2,4‐triazepines
Author(s) -
Afsah Elsayed M.,
ElDesoky ElSayed I.,
Etman Hassan A.,
Youssef Ibrahim,
Soliman Ahbarah M.
Publication year - 2018
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.3377
Subject(s) - chemistry , formaldehyde , hydrazine (antidepressant) , phenylhydrazine , aldehyde , mannich base , mannich reaction , amine gas treating , organic chemistry , diamine , hydrate , combinatorial chemistry , catalysis , chromatography
A series of tetrahydropyrimidines and bis‐(tetrahydropyrimidines) was synthesized by Mannich reaction of sec ‐emaminones with formaldehyde and the appropriate amine or diamine. Whereas the reaction with formaldehyde gave the dihydro‐1,3‐oxazine. Tetrahydropyrimidines incorporating a phenolic Mannich base were obtained by Mannich reaction of the appropriate tetrahydropyrimidine. The bis( sec ‐enaminones) were used as precursors in synthesis of bis(tetrahydropyrimidines) and bis(dihydro‐1,3‐oxazines). Treatment of the appropriate sec ‐emaminone or bis( sec ‐enaminone) with hydrazine hydrate or phenylhydrazine and a suitable aldehyde afforded dihydro‐1,2,4‐triazepines and the bis(dihydro‐1,2,4‐triazepines).