Synthesis, characterization and coordination chemistry of substituted β-amino dicarbonyls

Abstract

International audienceAn efficient and facile method for the synthesis of novel structurally diverse β-amino dicarbonyl compounds is described by exploring the aza-Michael addition reaction in an aqueous medium as a key step. Thereby, 2-(aryl-disubstituted-amino-1-yl-methyl)-malonic acid diethyl esters were achieved in a good to excellent yields. These products were easily isolated with enough purity just by using simple recrystallization. The crystals of the compounds (17) and (24) have been obtained and studied by X-ray crystallographic analyses

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

“…The formation of adducts occurs without a catalyst, usually in high yields. This conclusion can be illustrated by recent examples of the uncatalyzed aza-Michael reaction with geminal [22] or vicinal substituted alkenes. [23][24][25][26][27] For example, arylidene malonic acid diethyl esters 13 react quickly (unfortunately, the time is not specified) with various secondary amines as well as pyrazoles under non-catalytic conditions to provide expected adduct 14 in good to high yields (Scheme 3).…”

“…The formation of adducts occurs without a catalyst, usually in high yields. This conclusion can be illustrated by recent examples of the uncatalyzed aza‐Michael reaction with geminal [22] or vicinal substituted alkenes [23–27] …”

“…[23][24][25][26][27] For example, arylidene malonic acid diethyl esters 13 react quickly (unfortunately, the time is not specified) with various secondary amines as well as pyrazoles under non-catalytic conditions to provide expected adduct 14 in good to high yields (Scheme 3). [22] The addition of amines to unsaturated diazoketones 15 is proved to be very dependent on the type of Michael acceptor and amine nature (Scheme 4). For example, no catalyst is necessary when primary amines are employed, but in some cases the use of basic catalyst is crucial when secondary amines are introduced into the reaction.…”

“…Finally, the aza-Michael addition of aniline to 5 a is successfully promoted by Nheterocyclic carbene, [60] enzyme, [61] ionic liquids [62,63] or phasetransfer catalyst [64] (Table 1, entries [17][18][19][20][21]. When the reaction is performed under the same conditions in various solvents (including water) without a catalyst, the target adduct is isolated in low yields or does not formed at all (Table 1, entries [22][23][24][25]. Conversely, it is reported that water is the solvent of choice for this transformation.…”

“…For example, arylidene malonic acid diethyl esters 13 react quickly (unfortunately, the time is not specified) with various secondary amines as well as pyrazoles under non‐catalytic conditions to provide expected adduct 14 in good to high yields (Scheme 3). [22] …”