Zinc is not required for activity of TPO agonists acting at the c-Mpl receptor transmembrane domain.

Molecules that mimic the cytokine thrombopoietin that act by an atypical mechanism of binding to a receptor transmembrane (TM) domain are widely understood to require zinc for their biological activity. We investigated potent thrombopoietin mimetics from three chemical classes including the recently registered drug Eltrombopag, which operate via this novel mechanism, to determine whether zinc is essential for inducing cell proliferation. Using addition of zinc and a potent metal chelator, we show that the existing paradigm is incorrect and the compounds exhibit excellent thrombopoietin-mimetic activity even in the presence of high concentrations of EDTA. The implications of these findings for the mechanism of action are discussed.

Reactions of Allyl Phenyl Ether in High-Temperature Water with Conventional and Microwave Heating.

In a systematic study, allyl phenyl ether (1) was heated in water for 1 h at temperatures of 180 degrees C and above. Parallel experiments were conducted with a conventionally heated autoclave and a recently developed microwave batch reactor. Relatively modest temperature differences resulted in diverse product distributions, and these were independent of the method of heating. Maximum conversion of 1 to 2-allylphenol occurred at 200 degrees C (56%) and to 2-methyl-2,3-dihydrobenzofuran at 250 degrees C (72%). Although 2-(2-hydroxyprop-1-yl)phenol comprised less than 1% of the product mixture at both 180 and 260 degrees C, it accounted for 37% at 230 degrees C. The reaction sequence was investigated by heating intermediates individually at selected temperatures up to 290 degrees C. Hydration of 2-allylphenol to 2-(2-hydroxyprop-1-yl)phenol was partially reversible. The work showed that high-temperature water constitutes an environmentally benign alternative to the use of acid catalysts or organic solvents and offers scope for interconversion of alcohols and alkenes.