Michael Addition Reaction Catalyzed by Imidazolium Chloride to Protect Amino Groups and Construct Medium Ring Heterocycles

Abstract

An effective approach for amino protection and construction of a seven-membered ring has been developed. The method uses imidazolium chloride to carry out the Michael addition reaction at low temperatures and perform amino deprotection or construction of a seven-membered ring at high temperatures.

Aza‐Michael Reaction: A Decade Later – Is the Research Over?

“…Remarkable achievements in the addition of aliphatic and/ or aromatic amines to methyl vinyl ketone (5 a), acrylic acid derivatives -nitrile (1), esters (2 a, b) and N,N-disubstituted acrylamides 3 -were made through the use of ionic liquids such as [DDPA][HSO 4 ], [169] [TMPSA][HSO 4 ], [63] [HIm][TFA], [151] [HIm][Cl], [168]…”

“…Remarkable achievements in the addition of aliphatic and/or aromatic amines to methyl vinyl ketone ( 5 a ), acrylic acid derivatives – nitrile ( 1 ), esters ( 2 a , b ) and N,N‐disubstituted acrylamides 3 – were made through the use of ionic liquids such as [DDPA][HSO 4 ], [169] [TMPSA][HSO 4 ], [63] [HIm][TFA], [151] [HIm][Cl], [168] [DABCO‐PDO][OAc], [DABCO‐PDO][BF 4 ], [DABCO‐PDO][PF 6 ], [DABCO‐PDO][OTf], [170] [DABCO‐PDO][OAc], [163] [ADPQ][OAc], [ADPQ][BF 4 ], [ADPQ][PF 6 ], [ADPQ][OTf], [165] [dbIm][OH], [daIm][OAc], [167] EAN/EAA, DEAN/DEAA, TBAN/TBAA, [171] [TMG][Lac] [166] . The basic ionic liquids ([DBU][OAc] or [DBU][Lac]) were found to be an efficient catalysts for aza‐Michael addition of primary and secondary aliphatic and aromatic amines to 16‐dehydropregnenolone.…”

Hydroxyl carboxylate anion catalyzed depolymerization of biopolyesters and transformation to chemicals

“…16 N-Heterocyclic amides, such as benzimidazoles, benzothiazoles, benzothiazinones, pyrazolidines and benzodiazepines, represent key structural motifs in pharmaceutically important N-containing compounds, and oen serve as attractive synthetic targets in organic synthesis, life science, agrochemical industry and functional materials. They can be produced from the reactions of desired amines with hydroxyl carboxylic acids and their derivatives, [24][25][26][27] but suffer from their inherent shortcomings. Considering the structures of biopolyesters derived from self-condensation of hydroxyl carboxylic acids, they may serve as carbonylation feedstocks for synthesis of N-heterocyclic amides, which is however seldom reported.…”