| abstract |
A compound of Formula (I): ** Formula ** or a pharmaceutically acceptable salt thereof, in which: A is an optionally substituted nitrogen-containing heterocyclyl or heteroaryl; L is -C (R3) (R3) -, -O-, -S- or -NR3-; R1 is hydrogen or C1-C6 alkyl, C1-C6 alkenyl, C1-C6 alkynyl, carbocyclyl or heterocyclyl; R2 is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl or C1-C6 alkoxy; each R3 is independently hydrogen or C1-C6 alkyl; R5 is absent or is hydrogen; and represents a single or double link, in which when one of them is a double link, the other is a single link; and when one of the two is a double link, R5 is absent. |