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Utility of Ketonic Mannich Bases in Synthesis of Some New Functionalized 2‐Pyrazolines
Author(s) -
Afsah Elsayed M.,
Keshk Eman M.,
AbdelRahman AbdelRahman H.,
Jomah Najla F.
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.3055
Subject(s) - chemistry , mannich base , phenylhydrazine , alkylation , base (topology) , piperazine , organic chemistry , transamination , mannich reaction , medicinal chemistry , ketone , combinatorial chemistry , catalysis , mathematical analysis , mathematics , enzyme
The styryl ketonic Mannich base 2 has been used as a precursor in the synthesis of 2‐pyrazolines having a basic side chain at C‐3 and a phenolic Mannich base at C‐5. Treatment of the bis(styryl ketonic bases) 6a and 8a with phenylhydrazine affords the bis(3‐functionalized 2‐pyrazolines) 7 and 9 . The transamination between the styryl keto base 10 and 4‐aminoantipyrine leads to 12 , which reacts with piperazine to give 13 . N ‐Nitrosation of the sec ‐Mannich bases 15a – d followed by reductive cyclization affords 2‐pyrazolines 17a – d . The keto base 14b has been used for the synthesis of 2‐pyrazolines having a phenolic Mannich base at C‐3 and its reaction with 3,5‐dimethyl‐1 H ‐pyrazole affords 23 . The alkylation of 3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐one with the bis(Mannich base) 25 was investigated.