Utility of Ketonic Mannich Bases in Synthesis of Some New Functionalized 2-Pyrazolines
作者:Elsayed M. Afsah、Eman M. Keshk、Abdel-Rahman H. Abdel-Rahman、Najla F. Jomah
DOI:10.1002/jhet.3055
日期:2018.1
piperazine to give 13. N‐Nitrosation of the sec‐Mannichbases 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‐1H‐pyrazole affords 23. The alkylation of 3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐one with the bis(Mannich base) 25 was investigated.
Chemoselective aminomethylation of bifunctional substrates: carbonyl versus phenolic hydroxyl, carbonyl versus pyrazole and pyrrole versus phenolic hydroxyl as competing activating groups
作者:Gheorghe Roman
DOI:10.1016/j.tetlet.2014.01.005
日期:2014.2
Chemoselectivity in the Mannich reaction for three different types of bifunctional substrates has been investigated. 1-Hydroxy-2-naphthalenylethanone affords either phenolic Mannichbases at high pH (free amines), or ketonic Mannichbases at low pH (amine hydrochlorides), whereas the use of N,N-dimethylmethyleneiminium chloride as a preformed dimethylaminomethylation reagent gave the phenolic Mannich base. 1-Ar