Abstract Eleven new bisphosphonates were prepared from naturally-occurring 1-amino acids. The synthesis required special attention to amino and side-chain protections. The novel compounds were tested in TPTX (thyroparathyroidectomized) rats against arotinoid- induced hypercalcemia and were compared to alendronate. Most of the compounds showed moderate to no anti-resorptive activity. Two compounds were more active than clodronate, ...