Abstract: Compounds of the formula wherein X in each of formulas (1) and (2) represents a substituted or unsubstituted alkylene, alkenylene, or alkynylene linker of 2-6C; Y is of the formula or a stereoisomer thereof, wherein R1 is substituted or unsubstituted alkyl; each R2 is independently H, hydroxy, alkoxy (1-6C) or lower alkyl (1-4C); R3 is H, hydroxy, or alkoxy (1-6C); or Y is of the formula wherein each n is 1, Z is N, K comprises a substituted or unsubstituted aromatic carbocyclic or heterocyclic ring system which may optionally be spaced from the linkage position shown in formula (7) by a linker of 1-2C, or in formula (7), Z may be spaced from the carbon bonded to X by ?CR6— wherein R6 is H or linear, branded or cyclic alkyl (1-6C), R5 is H or linear, branched or cyclic alkyl, and R? represents a cation, H or a substituted or unsubstituted alkyl group of 1-6C, promote bone formation and are thus useful in treating osteoporosis, bone fracture or deficiency, primary or secondary hyperparathyro