Abstract: The present invention provides a compound of formula (I), or a pharmaceutically acceptable salt or solvate thereof, wherein: Y is selected from C or N; X is selected from O or S; R1 is selected from hydrogen or methyl; Z is CR2R3, wherein R2 and R3 are each independently selected from hydrogen and (1-5C)alkyl, or R2 and R3 are taken together with the carbon atom to which they are attached to form a cyclopropyl or cyclobutyl ring; Z1 is selected from CR4R5, O, S, C(O) or NR6, wherein R4 and R5 are each independently selected from hydrogen, OH, (1-5C)alkyl and phenyl, or R4 and R5 are taken together with the carbon atom to which they are attached to form a cyclopropyl ring, and R6 is selected from hydrogen and (1-5C)alkyl, provided that one, but not both, of Z and Z1 is CH2.

Abstract: The present invention provides a compound of formula (I), or pharmaceutically acceptable salt or solvate thereof, wherein: Y is selected from C or N; X is O; bond a is a single or double bond; x is 1 when a is a single bond and x is 0 when a is a double bond; R1 is selected from hydrogen and methyl; R2 (when present) is selected from hydrogen and methyl; R3 is selected from hydrogen, (1-6C)alkyl and (1-6C)alkyl-phenyl, wherein said phenyl is optionally substituted by one or more (for example 1 to 3) substituents each independently selected from hydroxy, (1-6C)alkoxy, (1-6C)alkyl and halo (such as chloro and fluoro).

Abstract: The invention relates to polymeric transition metal catalysts, to processes for preparing them, to intermediates and also to the use of the transition metal catalysts as catalysts in organic reactions, in particular in olefin metathesis reactions.

Abstract: The invention relates to polymeric transition metal catalysts, to processes for preparing them, to intermediates and also to the use of the transition metal catalysts as catalysts in organic reactions, in particular in olefin metathesis reactions.

Abstract: The invention relates to polymeric transition metal catalysts, to processes for preparing them, to intermediates and also to the use of the transition metal catalysts as catalysts in organic reactions, in particular in olefin metathesis reactions.

Abstract: The invention relates to polymeric transition metal catalysts, to processes for preparing them, to intermediates and also to the use of the transition metal catalysts as catalysts in organic reactions, in particular in olefin metathesis reactions.