Compounds and use thereof in the expansion of stem cells and/or progenitor cells

A method for expanding stem cells and/or progenitor cells, said method comprising contacting a starting cell population with a compound of formula I

• or a pharmaceutically acceptable salt thereof, wherein
• X is O or S;
• V1 is N or CH;
• V2 is N or CH;
• W is N or C;
• wherein not more than one of said V1, V2 and W is N;
• R1 is halo, alkyl, fluoroalkyl, cycloalkyl, alkynyl, alkenyl, cyano, or COORa, wherein Ra is an alkyl;
• R2 is H, or alkyl and R2 is absent when W is N;
• or R1 and R2 are attached together with the aromatic ring atoms to form a carbocyclic ring;
• R3 is a substituted phenyl, a substituted 5- or 6-membered heteroaryl, or
• a substituted fused bicyclic heteroaryl.