1-Arylethanones are readily chlorinated with an aqueous HCl-H 2 O 2 system using ethanol as a cosolvent. The reaction proceeds rapidly and results in selective conversion of 1-arylethanones into 1-aryl-2,2-dichloroethanones in yields of 48-89%, depending on the nature of the substituent in the aryl group.

No abstract

Condensation of aromatic (heteroaromatic) aldehydes with 1,3 dicarbonyl com pounds under the 1 butyl 3 methylimidazolium tetrafluoroborate ([Bmim][BF 4 ]) ionic liq uid-piperidinium acetate catalytic system (0.2 equiv. of each component) in the absence of a solvent affords, depending on the structures of the reagents, 2 arylidene derivatives of methyl acetoacetate and acetylacetone, diethyl 2,4 bis(trifluoroacetyl) 3 phenylpentanedioate, or di methyl 2 aryl 4 hydroxy 6 oxocyclohexane 1,3 dicarboxylates. The reactions of the resulting 2 arylidene derivatives with O methylisourea in the [Bmim] [BF 4 ] ionic liquid produced me thyl 2 methoxy 4 methyl 6 aryldihydropyrimidine 5 carboxylates and 1 (2 methoxy 4 me thyl 6 phenyldihydropyrimidin 5 yl)ethanone (mixtures of 3,6 and 1,6 dihydro isomers), which were transformed into the corresponding 3,4 dihydropyrimidin 2(1H ) one derivatives.

Tri-and tetraalkylammonium, 1,3-dialkylimidazolium, and 1,2,3-trialkylimidazolium salts with BF 4 -, PF 6 -, AlCl 4 -, and Al 2 Cl 7 as counterions catalyze the Biginelli reaction, ensuring preparation of various 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidine-2(1H)-thione derivatives in high yields in the absence of a solvent.

No abstract