The (±)-Monastrol 1 is pharmaceutically important compound with potent anti-cancer activity
[1,2] and it can be used as substrate for the chemical resolution via a site selective
functionalization of them with chiral electrophiles [3]. It is well known that the three-component
reaction between ethyl acetoacetate, urea and an aldehyde, under Brönsted acidic catalysis
affords 3,4-dihydropyrimidin 2(1H)-ones. However, this reaction suffers from the harsh
conditions, long reaction times and frequently low yields. Previously reported on a convenient
procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones 2 catalyzed by imidazolium salt
mixture 3a/4a or 3b/4b, at 100-125°C [4].

Herein, we wish to report the properties of the ionic liquid 3c and 4c [5].

We examined the reaction of ethyl acetoacetate with 3-hydroxybenzaldehyde and urea in the
presence of salts 3c and 4c (1.0 mol%) [5] at elevated temperatures. Both reactions gave rise to
the target (±)-Monastrol 1, which was formed in good yield.
The author thanks the bilateral MD-UC project (Ref. № 14.820.18.02.06/U) for financial
support and Prof. Macaev F. and Dr. Stîngaci E. for helpful discussions.
References:
1. Maliga Z., Kapoor T.M., Mitchison T.J. Chem. Biol. 2002, 9, 989.
2. DeBonis S., Simorre J.P., Crevel I., Lebeau L., Skoufias D. A., Blangy A., Ebel C., Gans
P., Cross R., Hackney D.D., Wade R.H., Kozielski F. Biochemistry 2003, 42, 338.
3. Singh K., Singh S. Tetrahedron 2009, 65, 4106.
4. Makaev F., Styngach E., Muntyanu V., Pogrebnoi S., Rybkovskaya Z., Barba A. Russ.
J.Org. Chem.2007, 43, 1512.
5. Buzhor S. In: The International Conference dedicated to the 55th anniversary from the foundation of
the Institute of Chemistry of the Academy of Sciences of Moldova. May 28 - 30, 2014, Chişinău.
Book of abstr. Chişinău, Moldova, 2014.