The present invention provides a novel compound having P2X3or P2X2/3receptor antagonism.Provided is a compound of formula (I):(wherein Ra, Rband Rcare (a) Raand Rbtogether form=Z, Rcis a group represented by R1c, or (b) Raand Rbtogether form a bonding, Rais a group represented by -Y-R1a, R1aand R1care independently hydrogen, or substituted or unsubstituted alkyl and the like, R2and R3are independently aryl and the like, R4aand R4bare independently hydrogen, or substituted or unsubstituted alkyl and the like, X is -N-(R5)- and the like, R5is substituted or unsubstituted lower alkyl and the like； Y is -O- and the like； Z is =O and the like； n is an integral of 0~4).本發明提供新穎之具有P2X3或P2X2/3受體拮抗作用的化合物。提供式(I)所示的化合物：(式中，Ra、Rb及Rc為(a)Ra與Rb一起形成=Z，Rc為R1c所示的基，或(b)Rb與Rc一起形成鍵結，Ra為-Y-R1a所示的基，R1a及R1c各自獨立為氫、取代或非取代之烷基等，R2及R3各自獨立為取代或非取代之芳基等，R4a及R4b各自獨立為氫、取代或非取代之烷基等，X為-N(R5)-等，R5為氫、取代或非取代之低級烷基等，Y為-O-等，Z為=O等，n為0～4之整數)。
