Compositions and methods for promoting the generation of definitive endoderm

A method of producing a definitive endoderm cell from a pluripotent stem cell comprising contacting a population of pluripotent stem cells with at least one compound of Formula (I) that activates TGF-β signaling, thereby inducing the differentiation of at least one pluripotent stem cell into a definitive endoderm cell, wherein the definitive endoderm cell expresses Sox17, or HNF3B (FoxA2), or Sox17 and HNF3B (FoxA2) and wherein the compound of formula (I) is:

• wherein:
• R1 and R2 are independently H, alkyl, alkenyl, alkynyl, aryl, heteroaryl, cyclyl, or cyclyl, each of which can be optionally substituted and/or can be interrupted in the backbone with one or more of O, N, S, S(O), and C(O);
• R3 and R4 are independently H, halogen, alkyl, alkenyl, alkynyl, alkoxy, aryl, heteroaryl, cyclyl, or cyclyl, each of which can be optionally substituted, or R3 and R4 together with the carbon to which they are attached from an optionally substituted cyclyl or heterocyclyl;
• and
• L is C1-C10 alkylenyl, C2-C10 alkenylenyl, or C2-C10 alkynylenyl, each of which can be optionally substituted and/or can be interrupted in the backbone with one or more of O, N, S, S(O), and C(O).