The invention provides a compound of formula (I) or a pharmaceutically acceptable ester, amide, carbamate, solvate or salt thereof, including a salt of such an ester, amide or carbamate, and a solvate of such an ester, amide, carbamate or salt. The invention also provides also provides the use of such compounds in the treatment or prophylaxis of a condition associated with a disease or disorder associated with estrogen receptor activity, wherein R1, R2, R3, R4, R5 and R6 are as defined in the specification.
