Patent ID: 7465821

Claim:
A process for the preparation of 2-alkylidene-1,4-dions derivatives of formula (Ia) or (Ib) or a mixture of (Ia) and (Ib): wherein R 1 , R 2 and R 3 , equal to or different from each other, are hydrogen atoms or C 1 -C 20 hydrocarbon groups, optionally containing heteroatoms belonging to group 13-17 of the periodic table, or R 1 and R 2 can join together to form a saturated or unsaturated C 3 -C 10 ring, optionally containing heteroatoms belonging to group 13-17 of the periodic table, with the proviso that when R 1 and R 2 are both hydrogen atoms, only compounds of formula (Ia) are obtained; T 1 and T 2 , equal to or different from each other, are H, OR 4 , R 4 , NR 4 2 , SR 4 or PR 4 2 , or T 1 and T 2 can be fused in an oxygen atom or a NR 4 group; R 4 , equal to or different from each other, are a C 1 -C 20 hydrocarbon group, optionally containing one or more heteroatoms belonging to group 13-17 of the periodic table; said process comprising the step of reacting a compound of formula (II): with a compound of formula (IIIa) or (IIIb): in the presence of at least one equivalent with respect to the compound of formula (IIIa) or (IIIb) of a salt of a base or a neutral base at a temperature higher than 70° C.