Synthesis and in vivo anti- or pro-inflammatory activity of new bisphosphonates and vinylphosphonates

Abstract

We herein report the synthesis and in vivo anti-inflammatory activity of a series of new bisphosphonate and vinylphosphonate derivatives of pyrrolidine and piperidine through a short route of synthesis. The C-alkylation of tetraethylmethylene diphosphonate with N-(bromoacetyl)pyrrolidine or N-(bromoacetyl)piperidine, respectively, yielded the corresponding α-substituted bisphosphonates in excellent yields (82–89%). Next, the Horner–Wadsworth–Emmons reaction of these bisphosphonates with aromatic aldehydes afforded final vinylphosphonates in moderate yields (26–36%). Synthesized bisphosphonates and vinylphosphonates were tested by two models of acute inflammation in male BalB/c mice, founding excellent edema inhibition by topical TPA (12-O-tetradecanoylphorbol-13-acetate) model (67.53–72.10% in comparison with indomethacin = 64.89%). However, remarkably pro-inflammatory effect by systematic carrageenan model (− 9.78 to − 36.18) was observed, probably due to biotransformation. In conclusion, the new vinylphosphonates emerged as attractive topical anti-inflammatory compounds that “twist” its pharmacological activity to route of administration. Further research is needed to understand the dual effect.