Patent ID: 7674910

Claim:
A process for preparing diimine compounds, which comprises reacting a dicarbonyl compound with primary amines in presence of phosphorus pentoxide, wherein the diimine compounds are of formula I, wherein: R 1 -R 2 are the same, and are selected from hydrogen, C 1 -C 22 -alkyl, C 2 -C 22 -alkenyl, C 6 -C 22 -aryl, alkylaryl comprising from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, or a five-, six- or seven-membered heterocycle comprising at least one atom from the group consisting of N, P, O and S, wherein R 1 -R 2 may be substituted by at least one halogen or SiR 6 3 and/or two R 1 -R 4 may be joined with one another or with A to form a ring; R 3 -R 4 are the same, and are selected from hydrogen, C 1 -C 22 -alkyl, C 2 -C 22 -alkenyl, C 6 -C 22 -aryl, alkylaryl comprising from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, or a five-, six- or seven-membered heterocycle comprising at least one atom from the group consisting of N, P, O and S, wherein R 3 -R 4 may be substituted by at least one halogen or SiR 6 3 and/or two R 1 -R 4 may be joined with one another or with A to form a ring; R 6 are each, independently of one another, hydrogen, C 1 -C 22 -alkyl, C 2 -C 22 -alkenyl, C 6 -C 22 -aryl or alkylaryl comprising from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, and two R 6 may be joined to form a five- or six-membered ring; m is 1; A has formula III: wherein: E 1 is nitrogen; E 2 -E 4 are each carbon; R 17 -R 19 are each hydrogen; and u is 1; and the dicarbonyl compound is of formula II, wherein: R 1 -R 2 are the same, and are selected from hydrogen, C 1 -C 22 alkyl, C 2 -C 22 -alkenyl, C 6 -C 22 -aryl, alkylaryl comprising from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, or a five-, six- or seven-membered heterocycle comprising at least one atom from the group consisting of N, P, O and S, wherein R 1 -R 2 may be substituted by at least one halogen or SiR 6 3 and/or two R 1 -R 4 may be joined with one another or with A to form a ring; R 6 are each, independently of one another, hydrogen, C 1 -C 22 alkyl, C 2 -C 22 alkenyl, C 6 -C 22 -aryl or alkylaryl comprising from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, and two R 6 may be joined to form a five- or six-membered ring; m is 1; and A has formula III: wherein: E 1 is nitrogen; E 2 -E 4 are each carbon; R 17 -R 19 are each hydrogen; and u is 1.