Structure–activity relationship and crystallographic studies on 4-hydroxypyrimidine HIF prolyl hydroxylase domain inhibitors by Holt-Martyn, JP, Chowdhury, R, Tumber, A, Yeh, T-L, Abboud, MI, Lippl, K, Lohans, CT, Langley, GW, Figg Jr, W, McDonough, MA, Pugh, CW, Ratcliffe, PJ, Schofield, CJ