Synthesis and Evaluations of "1,4-Triazolyl Combretacoumarins" and Desmethoxy Analogues.

ABSTRACT: 1,4-Triazolyl combretacoumarins have been prepared by linking the trimethoxyarene unit of combretastatin A4 with coumarins, via a 1,2,3-triazole. For this, 4-azidocoumarins were accessed by a sequential two-step, one-pot reaction of 4-hydroxycoumarins with (benzotriazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), followed by reaction with NaN₃. In the reaction with BOP, a coumarin-derived phosphonium ion intermediate seems to form, leading to an O ⁴-(benzotriazolyl)coumarin derivative. For the CuAAC reaction of azidocoumarins with 5-ethynyl-1,2,3-trimethoxybenzene, catalytic [(MeCN)₄Cu]PF₆ in CH₂Cl₂/MeOH with 2,6-lutidine, at 50 °C, was suitable. The 4-azidocoumarins were less react

SUBMITTER: Khandaker TA 

PROVIDER: S-EPMC6774347 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature