The present invention provides compositions and methods for differentiating and transdifferentiating mammalian cells into cells of an osteoblast lineage, using compounds of the following formula: ##STR00001## wherein R.sup.4 is a functional group including, for example, C.sub.1-4alkyl, C.sub.3-8cycloalkyl, hydroxyl-C.sub.1-4alkyl, aryl-C.sub.0-3alkyl, substituted with 0-2 R.sup.4a groups, and heterocyclo-C.sub.0-2alkyl, optionally substituted with C.sub.1-4alkyl; R.sup.5 is hydrogen and R.sup.6 is a functional group including, for example, halogen, C.sub.1-4alkyl, --C(O)--C.sub.1-4alkyl, --SO.sub.2--N(R.sup.2b R.sup.2b), halo--C.sub.1-4alkyl, --O-aryl and --N(R.sup.7 R.sup.8), or when R.sup.5 and R.sup.6 are on adjacent ring atoms they are optionally taken together to form --O--(CH.sub.2).sub.1-2--O--; and all pharmaceutically acceptable salts and hydrates thereof.