Synthesis for quinacridone compounds
View Patent ↗Disclosed is a process for forming a N,N′-diarylquinacridone compound comprising the step of reacting a 1,4-dialkylcarboxylate-2,5-bis(N-arylamino) benzene with an iodoaryl compound to form the corresponding 2,5-bis(N-diarylamino) compound. The process is versatile and provides high yields and purity for the synthesis of N,N′-diarylquinacridone compounds.
1. A process comprising reacting a 1,4-dialkylcarboxylate-2,5-bis(N-arylamino) benzene with an iodoaryl compound in the presence of a base and copper in elemental form or in the (I) or (II) valence state to form the corresponding 2,5-bis(N-diarylamino) compound and then forming a quinacridone compound by subjecting the 2,5-bis(N-diarylamino) compound to a condensation reaction.
2. The process of claim 1 wherein the copper comprises Cu, CuI, CuCl 2 , or Cu 2 O.
3. The process of claim 1 wherein the iodoaryl compound is a substituted iodo-phenyl compound.
4. The process of claim 1 wherein the N-arylamino group is a N-phenylamino group.
5. The process of claim 1 wherein the dialkylcarboxylate is a dimethyl carboxylate.
6. The process of claim 1 wherein the benzene ring or at least one of the aryl groups is substituted with a group having a Hammett's σ constant at least 0.05 more positive than the corresponding methyl group.
7. The process of claim 6 wherein the substituted group is selected from the group consisting of halogen, aryl, an aromatic heterocycle, or a fused aromatic or heteroaromatic ring.
8. The process of claim 7 wherein the substituted group is selected from the group consisting of phenyl, biphenyl, and naphthyl groups.
9. The process of claim 1 wherein there are optionally up to 4 substituents on the aryl rings.
10. The process of claim 1 wherein the reaction is performed at a temperature of at least 80° C.
11. The process of claim 1 wherein the reaction is performed at a temperature of at least 100° C.
12. The process of claim 1 wherein the reaction is performed at a temperature of at least 150° C.
13. The process of claim 1 wherein the reaction is performed in the presence of an organic solvent having a boliling point of at least 80° C.
14. The process of claim 13 wherein the solvent comprises toluene or dichlorobenzene.
15. The process of claim 1 wherein the base is selected from carbonates, hydroxides, phosphates, alkoxy and hydrides.
16. A process for preparing an N, N′-diarylquinacidone capable of fluorescent emission in the green region comprising performing the reactions of claim 1 and then condensing the product to form a diarylquinacridone compound.
17. A process for forming an N, N′-diarylquinacridone compound comprising the steps of condensing a 1, 4-dialkylcarboxylate-2, 5-hydroxy 1, 4-cyclohexadiene with an arylamine to form the corresponding 1, 4-dialkylcarboxylate-2, 5-bis (arylamino) 1, 4-cyclohexadiene, followed by oxidation of the cyclohexadiene to the corresponding benzene compound, followed by the reactions of claim 1 .