Abstract
Aspects are presented of the acylation of amines, alcohols, and thiols with 5-(α-amino-α′-hydroxy)methylene Meldrum acids. We placed special emphasis on the acylation reaction of secondary amines with 5-(α-amino-α′-hydroxy)methylene Meldrum acids, which, because of their basicity, caused problems concerning salt formation with a Meldrum acid derivative. We found that secondary amines, which react at the slowest rate and give a poor yield with 5-(α-amino-α′-hydroxy)methylene Meldrum's acid, react quickly and with high yields with the same reagent in the presence 1 to 3 equivalents of TMSCl. Acylation with this derivative of Meldrum acid was optimized for such factors as reaction temperature, solvent polarity, and acidity of the environment. We have prepared a wide range of nonsymmetrical malononic acid diamids, esters, and thioesters of malonamic acid.
GRAPHICAL ABSTRACT
ACKNOWLEDGMENT
This scientific work was financed from Funds for Science in 2010–2011 as Research Project NN204 088338.
Notes
a Equimolar amount of reagent.
b 2,5 eq of TFA was added.
c Reaction mixture was saturated with HCl.
d Excess of 1a was used.
Solvents A = DCM; B = benzene; C = dioxane, D = toluene, E = ethylbenzene.
Note. Solvents D, toluene; E, ethylbenzene; F, acetonitrile.