Starting from enantiomeric pure 1-[(3S,5R)- and 1-[(3R,5S)-3-(hydroxymethyl)-2-methylisoxazolidin-5-yl]-5-methylpyrimidine-2,4(1H,3H)-diones (-)7a and (+)7b, obtained by lipase-catalyzed resolution, pure diethyl{[(3S,5R)-2-methyl-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)isoxazolidin-3-yl]methyl}phosphonate (-)12a and diethyl{[(3R,5S)-2-methyl-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidi...

Trichloroacetic acid was found to be a convenient catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones and their corresponding 2(1H)-thiones through a one-pot three-component reaction of aldehydes, alkyl acetoacetate, and urea or thiourea at 70°C under solvent-free conditions.

A simple and economic synthesis of 3,4-dihydropyrimidin-2(1H)-ones using ammonium trifluoroacetate as catalyst and as solid support is accomplished. Easy workup procedure for the synthesis of title compounds is well arrived at and is well documented.

6'-(4-Chlorophenyl)-spiro[cyclohexane-1,2'-thieno[3,2-d][1,3] oxazin]-4'(1'H)-one (1) was synthesized and used as a starting material for the synthesis of a novel series of spiro compounds having biologically active sulfonamide 2a-e and 3'-(4-acetylphenyl)-6'- (4-chlorophenyl)-1'H-spiro[cyclohexane-1,2'-thieno[3,2-d] pyrimidine-4'(3'H)-one (3). Compound 2a was used as a key intermediate for the...

Reaction of ethyl-6-methyl-2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidin-5-carboxylates (1a-i) with hydrazine hydrate yielded 6-methyl-2-oxo-4-aryl-1,2,3,4-tetrahydropyrimidin-5-carbohydrazides (2a-i). These products, on reaction with cyanogen bromide, gave 5-(5-amino-1,3,4-oxadiazol-2-yl)-6-methyl-4-aryl-3,4-dihydropyrimidin-2 (1H)-ones (3a-i). The resultant aminooxadiazolylpyrimidinones were conde...

   This procedure has developed the use of TiO2 nanoparticles as an environmentally friendly and highly efficient heterogenous nanocatalyst for the eco-safe, facile and one-pot three-component Biginelli synthesis of biologically active corresponding 3,4-dihydropyrimidin-2-(1H)-one/thione derivatives under solvent-free conditions. This eco-friendly protocol provi...

In 1893, P. Biginelli reported the synthesis of functionalized 3, 4-dihydropyrimidin-2(1H)-ones (DHPMs) via three-component condensation reaction of an aromatic aldehyde, urea, and ethyl acetoacetate. In the past decade, this long-neglected multicomponent reaction has experienced a remarkable revival, mainly due to the interesting pharmacological properties associated with this dihydropyrimidin...