Acyl derivatives of demethylpenclomedine, an antitumor-active, non-neurotoxic metabolites of penclomedine

Carbonate and carbamate derivatives of 4-demethylpenclomedine as novel anticancer agents

PURPOSE

The purpose of this investigation was to synthesize a series of carbonate and carbamate derivatives of 4-demethylpenclomedine (DM-PEN), the major plasma non-toxic metabolite of penclomedine (PEN) seen in patients. DM-PEN has been observed to be an active antitumor agent in mouse human xenograft tumor models and non-neurotoxic in a rat model, however, activity in intracranially implanted human glioma xenograft models have not been reported. The major goal was to identify derivatives that are active in brain tumors.

METHODS

Derivatives were prepared from DM-PEN and evaluated in vivo against human U251 glioblastoma, D54 glioblastoma and MX-1 breast tumor xenografts and mammary tumor 16/C that were implanted in the mammary fat pad or intracranially (IC).

RESULTS

Carbonate and carbamate derivatives were found to be superior to DM-PEN against IC growing human glioblastoma xenografts.

CONCLUSION

The activity of the carbonates and carbamates against human tumor xenografts in vivo suggests consideration of these two series of derivatives of DM-PEN for clinical development.

Thiolo-, thiono- and dithiocarbonate and thiocarbamate derivatives of demethylpenclomedine as novel anticancer agents

PURPOSE

The purpose of this investigation was to synthesize a series of thiolo-, thiono- and dithiocarbonate and thiocarbamate derivatives of 4-demethylpenclomedine (DM-PEN), the major plasma metabolite of penclomedine (PEN) in patients observed subsequently to be an active antitumor agent and non-neurotoxic in a rat model, in order to compare their antitumor activity with that of DM-PEN.

METHODS

Derivatives were prepared from DM-PEN and evaluated in vivo against human MX-1 breast tumor xenografts implanted in the mammary fat pad, several of which were also evaluated against human brain tumor xenografts.

RESULTS

Thiolocarbonate and thiocarbamate derivatives were found to be superior to DM-PEN against MX-1 tumor and modestly active against glioblastoma.

CONCLUSION

The activity of the thiolocarbonates and thiocarbamates against human tumor xenografts in vivo suggests consideration of these two series of derivatives of DM-PEN for clinical development.

Determination of the phamacophore of penclomedine, a clinically-evaluated antitumor pyridine derivative

The main objective of this investigation was to identify the reactive pharmacophore in penclomedine (PEN, 3,5-dichloro-4,6-dimethoxy-2-(trichloromethyl) pyridine) for in vivo antitumor activity and also to discover related ring structures and sulfur analogues that might exhibit superior antitumor activity in vivo. Several new analogues of PEN and related structural variants have been synthesized and evaluated in vivo against MX-1 human breast tumor xenograft implanted subcutaneously (sc), although none of them demonstrated significant activity.

Synthesis and antitumor activity of several new analogues of penclomedine and its metabolites

Analogues of penclomedine (PEN, 3,5-dichloro-4,6-dimethoxy-2-(trichloromethyl)pyridine) and its metabolites have been synthesized and evaluated as potential antitumor agents. PEN and 4-DMPEN (3,5-dichloro-4-hydroxy-6-methoxy2-(trichloromethyl)pyridine (3a)), the major plasma metabolite in patients, were modified at 4- and 6-positions with different alkyl, aryl, and ester groups. All of the analogues and many of the intermediates were evaluated against the PEN-sensitive MX-1 human breast tumor xenograft in vivo, and several analogues of PEN and 4-DMPEN showed modest to curative activity.