Mj. Ahlmark et al., Bisphosphonate prodrugs: unusual dimerisation of clodronic acid trimethyl ester to a cyclic bis(bisphosphonate), CHEM COMMUN, (8), 2000, pp. 711-712
Cl2C[P(O)(OMe)(2)P(O)(OMe)(O(-)Z(+))] selectively reacts with acetyl chlori
de to provide a new enzymatically stable heterocyclic bis(bisphosphonate);
the structure is confirmed by X-ray crystallography.