Compounds of general formula or salts or prodrugs thereof, are provided and described herein. The compounds are useful to expand hematopoietic stem cell and/or hematopoietic progenitor cell populations. Particularly, the hematopoietic cells are human cells. The compounds are also useful in the medical treatment of hematopoietic disorder/malignancy, an autoimmune disease and/or an inherited immune-deficient disease in a subject.