abstract provided is a pyrazolopyrimidine compound represented by formula (i) having a hif-phd inhibitory effect, or a pharmaceutically acceptable salt thereof. [in the formula, represents an optionally substituted 7-hydroxypyrazolo [4,3-d] pyrimidine-5-yl, x represents a simple bond or an optionally substituted straight-chain alkylene, z represents hydrogen atom, or formula (i), formula (ii) or formula (iii), and rings are independently an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted alicyclic hydrocarbon, or an optionally substituted non-aromatic heterocycle.] ------ -------------------------------------------------- ------------------------------------------------- Translation from the abstract summary patent: "pyrazolopyrimidine compound". A pyrazolopyrimidine compound represented by formula (I) having an inhibitory effect of hypha-phd, or a pharmaceutically acceptable salt thereof, is provided. [in the formula aa indicates an optionally substituted 7-hydroxypyrazolo [4,3-d] pyrimidin-5-yl, x indicates a single bond or an optionally substituted straight chain alkylene, z denotes hydrogen atom, or formula (i) , formula (ii) or formula (iii), and rings a and 'are independently an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted hydrocarbon, or an optionally substituted non-aromatic heterocycle].abstract provided is a pyrazolopyrimidine compound represented by formula (i) having an hif-phd inhibitory effect, or a pharmaceutically acceptable salt thereof. [in the formula, represents an optionally substituted 7-hydroxypyrazolo[4,3-d]pyrimidine-5-yl, x represents a simple bond or an optionally substituted straight-chain alkylene, z represents hydrogen atom, or formula (i), formula (ii) or formula (iii) , and rings a and a' are independently an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted alicyclic hydrocarbon, or an optionally sub
