SUBSTITUTED 5-MEMBERED RING COMPOUNDS AND THEIR USE

Compound of a compound of formula (I) or a salt, N-oxide, hydrate or solvate thereof, in the preparation of a composition for inhibition of HSP90 activity: wherein ring A is an aromatic or non-aromatic carbocyclic or heterocyclic ring having 5 ring atoms, for example 1,2,3-triazolyl or a 1,2,4-triazolyl or a tetrazolyl ring; and R1 R2 R3 are as defined in the specification are inhibitors of HSP90 and therefore of use in the treatment of, for example, cancers, viral disease, inflammatory diseases such as rheumatoid arthritis, asthma, multiple sclerosis, Type I diabetes, lupus, psoriasis and inflammatory bowel disease; cystic fibrosis angiogenesis-related disease such as diabetic retinopathy, haemangiomas, and endometriosis; or for protection of normal cells against chemotherapy-induced toxicity; or diseases where failure to undergo apoptosis is an underlying factor; or protection from hypoxia-ischemic injury due to elevation of Hsp70 in the heart and brain; scrapie /CJD, Huntingdon's and Alzheimer's disease.