Biocatalysed olefin reduction of 3-alkylidene oxindoles by baker's yeast

Chemospecific C3- and C2-Olefinations of Isatins by TfOH-Promoted Tandem Aldol-Grob and Semiacetalization-Grob Fragmentations

A novel method for TfOH-promoted chemospecific C3- and C2-olefinations of isatins is developed, which offers the first examples of Grob fragmentation using isatins and amides as substrates.

In vitro degradation of ziprasidone in human whole blood

A systematic study was performed into the degradation of ziprasidone in simulated postmortem blood. Fifteen potential degradation products not previously reported in the literature were observed. Four resulted from degradation in human blood, whereas the remaining products resulted from reaction with solvents: four from alkaline degradation, four from reaction with acetaldehyde, and three from reaction with acetone. To identify possible degradation products, a liquid chromatograph-diode array detector (LC-DAD) and liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS) operating in auto-MS/MS mode were used. It was indicated from red-shifted UV-Vis spectra, accurate mass data, mass fragmentation data, and a deuteration experiment that the site of ziprasidone degradation, in the in vitro blood experiments, was the methylene carbon of the oxindole moiety. The major in vitro blood degradation products were proposed to be E/Z isomers of 3-ethylidene-ziprasidone. Further, another in vitro degradation product in microbially inoculated blood specimens was proposed to be 3-ethyl-ziprasidone. 3-Ethylidene-ziprasidone was hypothesized to form from the reaction of ziprasidone with acetaldehyde derived from the ethanol used to spike ziprasidone into the in vitro blood experiments. Data from two postmortem investigations were available for retrospective reanalysis. Attempts were made to detect degradation products of ziprasidone, but none were found.

Transition metal-free functionalization of 2-oxindoles via sequential aldol and reductive aldol reactions using rongalite as a C1 reagent

A sequential one-pot classical aldol, transition-metal and hydride-free reductive aldol reaction is reported here for C(sp3)- H functionalization of 2-oxindoles using the multifaceted reagent rongalite. Here, rongalite functions as a hydride-free reducing agent and double C1 unit donor. This protocol enables the synthesis of a wide range of 3-methylindoline-2-ones and 3-(hydroxymethyl)-3-methylindolin-2-ones from 2-oxindoles (65-95% yields), which are the synthetic precursors for many natural products. Some of the important aspects of this synthetic approach include one-pot methylation and hydroxymethylation, low-cost rongalite (ca. $0.03 per 1 g), mild reaction conditions and applicability to gram-scale synthesis.

Total synthesis of isatindigotindoline C

Total synthesis of isatindigotindoline C, a 3,3'-spiropyrrolidine oxindole alkaloid, is achieved in two steps using an exo-selective decarboxylative 1,3-dipolar cycloaddition as the key step. The synthesis verifies the originally assigned relative anti-stereochemistry for the bis-oxindole core of isatindigotindoline C.