| abstract |
A compound of formula (I) or a pharmaceutically acceptable salt or in vivo hydrolyzable ester thereof: <IMAGE> (I) wherein R is phenyl 4-hydroxy phenyl, or a 5- 6- membered heterocyclic ring containing up to three heteroatoms selected from oxygen, sulphur or nitrogen, optionally substituted with hydroxy, amino, halogen or C1-6 alkoxy; R1 represents hydrogen or C1-6 alkyl; R2 and R3 are the same or different and represent hydrogen, C1-6 alkyl, halogen, amino, hydroxy, or C1-6 alkoxy. Their preparation and use is described. |