| abstract |
A compound of formula (1): wherein A is -CH2CH2-, -CH=CH- or -C=-C-; B is aryl or heteroaryl; D is optionally present and is -C(O)-, -C(O)NH-, -C(O)CH2- or -C(O)CH2- O-; E is optionally present and is alkylene or heteroarylene; R1 is hydrogen or alkyl; R2 is hydrogen, alkyl, aryl, cycloalkyl, heteroaryl or heterocycloalkyl; R3 and R4 are the same or different and are each hydrogen, alkyl or cycloalkyl; and each R5 is the same or different and is alkyl, -alkyl-aryl or -alkyl-cycloalkyl, or R5-Si-R5 taken together form heterocycloalkyl; or a pharmaceutically acceptable salt thereof. |