Patent ID: 7932403

Claim:
A process for preparing a pyrrole derivative of the formula I wherein R 1 is hydrogen or a straight or branched, saturated or unsaturated C 1-30 hydrocarbon group which may comprise 1-5 oxygen atoms, 1-5 nitrogen atoms, 1-2 sulfur atoms, 1 selenium atom and/or 1-5 —NR 6 groups, which hydrocarbon group may be substituted with 1-5 optionally protected hydroxy groups, 1-5 —OR 7 groups, 1-5 —NR 8 R 9 groups, 1-5 halogen atoms and/or 1-5 optionally protected carboxy groups, in which hydrocarbon group 1-5 carbon atoms may form carbonyl groups and which hydrocarbon group or part of which hydrocarbon group may form one or more rings, R 2 is —OR 3 , —NR 10 CONR 11 R 12 , —NR 13 OR 14 , —ONR 15 R 16 or halogen, R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 are independently selected from hydrogen or a straight, branched and/or cyclic, saturated or unsaturated C 1-10 alkyl groups or aryl groups, both groups being optionally substituted with 1-3 optionally protected hydroxy or carboxy groups, 1-3 —OR 7 groups, 1-3 —NR 8 R 9 groups and/or 1-3 halogen atoms, the C 1-10 alkyl group optionally comprising 1-3 oxygen atoms, 1-3 nitrogen atoms and/or 1-3 —NR 6 groups, the C 1-10 alkyl group further optionally comprising or being substituted with 1 or 2 aryl groups, or a salt thereof, which process comprises the steps of reacting a compound of the formula II wherein R 2 is defined as above, or a salt thereof, with a compound of the formulae IIIa, IIIb or IIIc R 1 —NH 2 IIIa, R 1 —NH—COO − H 3 N + —R 1 IIIb R 1 —NH—SiR 17 R 18 R 19 IIIc, or mixtures thereof, wherein R 1 is defined as above, R 17 and R 18 are independently selected from straight, branched and/or cyclic C 1-10 alkyl group or aryl group; and R 19 is straight, branched and/or cyclic C 1-10 alkyl group, aryl group or —NH—R 1 , and, if necessary, converting the obtained pyrrole derivative having the substituent R 1 into a pyrrole derivative having a different substituent R 1 .