Patent ID: 8247576

Claim:
A compound having the formula (IV): or salt or tautomer thereof wherein z is 0, 1 or 2; R 1 is unsubstituted phenyl or phenyl substituted with 1, 2, 3 or 4 substituents independently selected from hydroxy, C 1-4 acyloxy, fluorine, chlorine, bromine, trifluoromethyl, cyano, C 1-4 hydrocarbyloxy and C 1-4 hydrocarbyl optionally substituted by C 1-2 alkoxy or hydroxy; R 2 and R 3 are independently selected from hydrogen and methyl; R 4 is selected from hydrogen and methyl; R 5 is selected from hydrogen and methyl; and R 20 is selected from hydrogen, methyl, hydroxy and fluorine, provided that when z is 0, R 20 is other than hydroxy.