Process for preparing aromatic and heteroaromatic amines
A process is described for preparing aromatic and heteroaromatic amines of the general formula (I) Ar—NR 1 R 2 , in which an aromatic compound with the general formula (II) Ar—X is reacted in the presence of a catalyst with an amine of the general formula (III) H—NR 1 R 2 and a base, wherein the catalyst is selected from transition metal complexes having one or more ligands with the general formula (IV).
1. A process for preparing aromatic amines of formula (I):
Ar—NR 1 R 2 (I)
where
Ar is a substituted or unsubstituted aryl, heteroaryl, arylalkyl, heteroarylalkyl radical,
R 1 and R 2 can be identical or different and are each H, a hydrocarbon group, a heteroatom-containing hydrocarbon group which may have suitable substituents, and the radicals R 1 and R 2 may form a ring which can be 4- to 20-membered, saturated or unsaturated, alicyclic or heteroalicyclic and may have suitable substituents,
said process comprising reacting an aromatic compound having formula II:
Ar—X (II)
where
Ar is as defined above and
X is F, Cl, Br, I or OSO 2 R 3 in which R 3 is a hydrocarbon group,
in the presence of a catalyst with an amine of formula III:
H—NR 1 R 2 (III)
where R 1 and R 2 are as defined above,
and a base,
wherein the catalyst is selected from among transition metal complexes which have one or more ligands having formula IV:
where
R 3 , R 4 , R 5 and R 6 can be identical or different and are each H, a linear or branched C 1 -C 6 -alkyl radical which may optionally be substituted or R 3 and R 4 and/or R 5 and R 6 are joined to one another to form a ring,
Y is halogen or an —OR 7 radical, where R 7 is H or a linear or branched C 1 -C 6 -alkyl chain which may optionally be substituted or an aryl radical which may optionally be substituted.
2. The process as claimed in claim 1 , wherein Y is Cl, Br or —OR 7 ,
where R 7 is i-propyl or tert-butyl.
3. The process as claimed in claim 1 , wherein R 3 and R 5 and/or R 4
and R 6 are i-propyl or tert-butyl.
4. The process as claimed in claim 1 , wherein the base is selected from among alkali metal hydroxides, alkali metal alkoxides, alkali metal carbonates, alkali metal phosphates, ammonia, C 1 -C 6 -alkylamine, di(C 1 -C 6 -alkyl)amine, benzylamine, piperidine and morpholine.
5. The process as claimed in claim 1 , wherein the transition metal is selected from among iron, palladium, nickel, cobalt, platinum, rhodium and ruthenium.
6. The process as claimed in claim 5 , wherein the transition metal complex is prepared from transition metal compounds selected from among Pd(OAc) 2 , Pd(acac) 2 , (allPdCl) 2 , PdCl 2 , Pd 2 (dba) 3 and Pd(dba) 2 .