One-pot condensation of 1,3-dicarbonyl compounds with a range of aldehydes in the presence of ammonium bicarbonate was carried out under solvent-free condition at 70 ℃ to afford 1,4-dihydro- pyridines in 86%～97% yields.

A new method for the halogenation of 1,3-dicarbonyl compounds;

Silica supported sodium hydrogen sulfate (NaHSO4?SiO2) has been found to be an efficient het- erogeneous catalyst for the condensation of 1,3-dicarbonyl compounds with primary amines to give the cor- responding β-enamino ketones and esters in good yields at room temperature.

A mixture of 1,2-carbonyl compounds(glyoxal trimer dihydrate,diethyl oxalate or benzil) with dimethyl diglycolate is refluxed via condensation for 6～8h in cyclohexane in the presence of KOH,and give furan-2,5-dicarboxylic acid,3,4-dihydroxyfuran-2,5-dicarboxylic acid and 3,4-diphenylfuran-2,5-dicarboxylic acid in the yields of 73.

A convenient and highly practical procedure for C-alkylation of 1,3-dicarbonyl compounds has been developed involving the use of ionic liquid based on 1-butylpyridinum tetrafluoroborate.

Synthesis of β-diketone from D-(+)-camphor;