Isothiourea-catalysed transfer hydrogenation of α,β-unsaturated para-nitrophenyl esters
作者:Jiufeng Wu、Claire M. Young、Andrew D. Smith
DOI:10.1016/j.tet.2020.131758
日期:2021.1
transfer hydrogenation of α,β-unsaturated para-nitrophenyl esters using Hantzsch ester has been developed. Good to excellent yields are observed using α,β-unsaturated aryl esters bearing electron-withdrawing β-substituents. The aryl ester products can either be isolated directly in moderate to excellent yields (7 examples, 16–98%) or converted to the corresponding methyl esters (2 examples, 68–70% yield)
A series of N-cinnamates of the A-ring pyrrole compound of duocarmycin were synthesized and evaluated for in vitro anticellular activity against HeLa S-3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. The 4'-methoxy- and 4'-BocNH-cinnamates exhibited strong in vitro anticellular activity among the synthesized compounds. The ortho substitution of the 4'-methoxycinnamate did not affect the anticellular activity and contributed to an enhancement of water solubility. Most of the 8-O-(N,N-dialkylcarbamoyl) derivatives of the 4'-methoxycinnamates displayed remarkably superior in vivo antitumor activity to duocarmycin A or B2. Moreover, it is noteworthy that these 8-O-(N,N-dialkylcarbamoyl) derivatives exhibited significant antitumor activity at wider range of doses as compared with the A-ring pyrrole derivatives having the trimethoxyindole skeleton in segment B.