Biginelli reaction starting directly from alcohols

An efficient of one-pot oxidative access to 3,4-dihydropyrimidin-2-(1H)-ones directly from aromatic alcohols under mild conditions is reported. The protocol involves 1-methylimidazolium hydrogen sulphate [Hmim]HSO4 catalyzed oxidation of aromatic alcohols to aromatic aldehydes with NaNO3 followed by their cyclocondensation with 1,3-dicarbonyl compounds and urea in the same reaction vessel at 80 degrees C within 2-4 h to afford 3,4-dihydropyrimidin-2-(1H)-ones in 55-97% overall yields. Thus, the present work utilizing alcohols instead of aldehyde in Biginelli reaction is a valid and green alternative to the classical synthesis of 3,4-dihydropyrimidin-2-(1H)-ones. (C) 2010 Elsevier Ltd. All rights reserved.