Isotopically labelly indlinone derivatives and process for their preparation

1 . A compound of general formula (I) below:

wherein

each R group is, at one or more of the positions 4, 5, 6 and 7 of the indolinone ring and independently from each other, a straight or branched C 1 -C 4 alkyl or alkoxy group or a halogen atom;

each R 1 group is, the same or different and at one or more of the positions of the pyrrole ring, a C 1 -C 4 alkyl or a group of general formula —(CH 2 ) p CO 2 R′, —(CH 2 ) p —CONR′R″ or —CONH—(CH 2 ) p —CONR′R″ wherein p is 0, 1, 2 or 3, the alkylene —(CH 2 ) p — chain is optionally substituted by hydroxy, and R′ and R″ are selected, each independently, from hydrogen or straight or branched C 1 -C 4 alkyl optionally substituted by hydroxy or, taken together with the nitrogen atom to which they are attached, R′ and R″ may form a pyrrolidino, piperidino or morpholino group;

m is 0 or an integer from 1 to 4;

n is 0 or an integer from 1 to 3;

or pharmaceutically acceptable salts thereof.

2 . A compound according to claim 1 wherein the pyrrole ring is substituted by one or more of the groups selected from methyl, carboxy, ethoxycarbonyl, carboxyethyl, N,N-diethyl-aminocarbonyl, N-[(2-diethylamino)ethyl]carboxamide or N-[2-hydroxy-3-morpholin-4-ylpropyl]carboxamide.

3 . A compound according to claim 1 which is 3-((3,5-dimethyl-1H-pyrrol-2-yl)[ 14 C]methylene-1,3-dihydro-2H-indol-2-one; 5-[(1,2-dihydro-2-oxo-3H-indol-3ylidene) [ 14 C]methyl]-2,4-dimethyl-1H-pyrrole-3-propionic acid; N-[(2-diethylamino)ethyl]-5-[(5-fluoro-1,2-dihydro-2-oxo-3H-indol-3-ylidene)[ 14 C]methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide; 3-{5-methyl-2-[(Z)-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)[ 14 C]methyl]-1H-pyrrol-3-yl)}propanoic acid; and 5-[(Z)-(5-fluoro-2-oxo-1,2-dihydro-3H-indol-3-ylidene) [ 14 C]methyl]-N-[(2S)-2-hydroxy-3-morpholin-4-ylpropyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide.

4 . A process for preparing a compound of formula (I) according to claim 1 which process comprises:

a) reacting dimethyl-[ 14 C]formamide with-a suitable pyrrole derivative of formula (II), in the presence of diphosphoryl-chloride

wherein R 1 and n are as defined in claim 1 , so as to obtain a compound of formula (III)

and optionally converting a compound of formula (III) into another compound of formula (III);

b) reacting under basic conditions the compound of formula (III) with an oxindole derivative of formula (IV)

wherein R and m are as defined in claim 1 , so as to obtain a compound of formula (I) and, optionally converting it into another compound of formula (I) and/or into a pharmaceutically acceptable salt thereof.

5 . A process according to claim 4 wherein, in step (b), basic conditions are obtained by means of pyrrolidine.

6 . A compound of formula (IIIa) or (IIIb) below

wherein R 1 is a hydrogen atom or a group selected from —(CH 2 ) 2 —CO 2 H, —CO 2 H, —CO 2 CH 2 CH 3 , —CONH—(CH 2 ) 2 —N(CH 2 CH 3 ) 2 and

7 . Use of a compound of formula (I), as defined in claim 1 , for absorption, distribution, metabolism and excretion (ADME) studies.