Improved Method for Preparation of 3-(1-Indol-3-yl)benzofuran-2(3)-ones.

3-(1-Indol-3-yl)benzofuran-2(3)-ones were efficiently accessed via polyphosphoric acid-mediated condensation of 3-(2-nitrovinyl)-1-indoles with phenols.

Direct Conversion of 3-(2-Nitroethyl)-1-Indoles into 2-(1-Indol-2-yl)Acetonitriles.

The recently discovered [4+1]-spirocyclization of nitroalkenes to indoles provided a convenient new approach to 2-(1-indol-2-yl)acetonitriles. However, this reaction was complicated by the formation of inert 3-(2-nitroethyl)-1-indole byproducts. Herein, we offer a workaround this problem that allows for effective transformation of the unwanted byproducts into acetonitrile target molecules.

[3 + 2]-Annulation of pyridinium ylides with 1-chloro-2-nitrostyrenes unveils a tubulin polymerization inhibitor.

Indolizines and pyrazolo[1,5-a]pyridines were prepared via [3 + 2]-cycloaddition of pyridinium ylides to 1-chloro-2-nitrostyrenes. The synthesized molecules were evaluated for antiproliferative activities against a BE(2)-C neuroblastoma cell line with several compounds decreasing the viability of cancer cells. Indolizine 9db showed higher potency than that of all-trans-retinoic acid, an approved cancer drug.

Electrophilically Activated Nitroalkanes in Synthesis of 3,4-Dihydroquinozalines.

Nitroalkanes activated with polyphosphoric acid serve as efficient electrophiles in reactions with various nucleophilic amines. Strategically placed second functionality allows for the design of annulation reactions enabling preparation of various heterocycles. This strategy was employed to develop an innovative synthetic approach towards 3,4-dihydroquinazolines from readily available 2-(aminomethyl)anilines.