Formation of 4,5,6,7-Tetrahydroisoindoles by Palladium-Catalyzed Hydride Reduction

Chalcogen bonding interactions in chelating, chiral bis(selenocyanates)

Both anti (racemic mixture) and syn (meso) forms of a chiral, chelating chalcogen bond (ChB) donor interact with halides through short Se⋯X⁻ directional interactions.

Synthesis of Jacaranone-Derived Nitrogenous Cyclohexadienones and Their Antiproliferative and Antiprotozoal Activities

The cytotoxic and antiprotozoal activities of the phytoquinoide, jacaranone, and related compounds have been an ongoing topic in recent drug discovery. Starting from the natural product-derived cyclohexadienone scaffold, a series of nitrogen-containing derivatives were synthesized and subsequently evaluated for their antiproliferative and antiprotozoal activity. Anticancer potency was analyzed using different types of cancer cell lines: MDA-MB-231 breast cancer, CCRF-CEM leukemia, HCT-116 colon cancer, U251 glioblastoma, and, in addition, non-tumorigenic MRC-5 lung fibroblasts. Antiproliferative activities at micromolar concentrations could be shown. Antiprotozoal activity was assessed against Plasmodium falciparum NF54 and Trypanosoma brucei rhodesiense STIB900. For all compounds, selectivity indices (SI) were calculated based on assessed cytotoxicity towards L6 cells. In addition, the structure-activity-relationships and physicochemical parameters of these compounds are discussed.

Reduction of Benzolactams to Isoindoles via an Alkoxide-Catalyzed Hydrosilylation

An alkoxide-catalyzed reduction of benzolactams to isoindoles with silanes was realized. With t-BuOK as the catalyst and Ph₂SiH₂ as the reductant, a series of benzolactams containing different functional groups were reduced to the corresponding isoindoles, which could be captured by N-phenyl maleimide to form Diels-Alder products in moderate to good yields. Deuterium labeling studies and the hydrosilylation of benzolactam in DMF indicated that the deprotonation of benzolactams took place at C3 potion during the reduction.

7-Hydroxy-3-methyleneisoindolin-1-one as a New ESIPT-Fluorescent Probe to Monitor Aqueous Environments

A 7-hydroxy derivative of 3-methyleneisoindolin-1-one 1 was synthesized and its properties as a new fluorophore undergoing excited-state intramolecular proton transfer (ESIPT) were investigated. In alcohols and dimethylsulfoxide, 1 exhibited dual emission at ca. 380 and 525-540 nm when excited at ca. 336 nm, which agreed well with the density functional theory (DFT) and time-dependent (TD)-DFT-calculated emission predictions of 1 and its ESIPT tautomer. In aqueous solutions at near neutral pH, 1 exhibited a broad emission band at ca. 497 nm, presumably caused by the overlap of emissions from 1 and the excited state phenolate species of 1. In binary mixtures of H₂O and EtOH, the wavelength and intensity of fluorescence maxima were dependent on the dielectric constant of the solvent, suggesting that 1 could be applied as a fluorescent probe to monitor aqueous environments.

Cu(ii) complex of a new isoindole derivative: structure, catecholase like activity, antimicrobial properties and bio-molecular interactions

An isoindole based trigonal bipyramidal Cu(ii) complex shows catecholase and antimicrobial activities. It interacts with bio-relevant antipyrine derivative.

Synthesis of isoindoles and related iso-condensed heteroaromatic pyrroles

Over the past few years, isoindoles have found wide application in materials science. Isoindole containing BODIPY dyes are highly fluorescent materials and have been extensively used in various fields of science. Phthalocyanines, metal containing cyclic tetramers of isoindole, form coordination complexes with most elements of the periodic table. These complexes are intensely coloured and are used as pigments and dyes. However, isoindoles are relatively unstable 10π-heteroaromatic systems and few synthetic methods provide these compounds in good yields. This tutorial review will give an overview of the reported synthetic methods towards isoindoles and related heteroaromatic systems over a time span of approximately 10 years (2000 to current), including the applications where they have been reported. The importance of the field will be illustrated and factors influencing product stability will be discussed.

Evaluation of donor and steric properties of anionic ligands on high valent transition metals

Synthetic protocols and characterization data for a variety of chromium(VI) nitrido compounds of the general formula NCr(NPr(i)(2))(2)X are reported, where X = NPr(i)(2) (1), I (2), Cl (3), Br (4), OTf (5), 1-adamantoxide (6), OSiPh(3) (7), O(2)CPh (8), OBu(t)(F6) (9), OPh (10), O-p-(OMe)C(6)H(4) (11), O-p-(SMe)C(6)H(4) (12), O-p-(Bu(t))C(6)H(4) (13), O-p-(F)C(6)H(4) (14), O-p-(Cl)C(6)H(4) (15), O-p-(CF(3))C(6)H(4) (16), OC(6)F(5) (17), κ(O)-N-oxy-phthalimide (18), SPh (19), OCH(2)Ph (20), NO(3) (21), pyrrolyl (22), 3-C(6)F(5)-pyrrolyl (23), 3-[3,5-(CF(3))(2)C(6)H(3)]pyrrolyl (24), indolyl (25), carbazolyl (26), N(Me)Ph (27), κ(N)-NCO (28), κ(N)-NCS (29), CN (30), NMe(2) (31), F (33). Several different techniques were employed in the syntheses, including nitrogen-atom transfer for the formation of 1. A cationic chromium complex [NCr(NPr(i)(2))(2)(DMAP)]BF(4) (32) was used as an intermediate for the production of 33, which was produced by tin-catalyzed degredation of the salt. Using spin saturation transfer or line shape analysis, the free energy barriers for diisopropylamido rotation were studied. It is proposed that the estimated enthalpic barriers, Ligand Donor Parameters (LDPs), for amido rotation can be used to parametrize the donor abilities of this diverse set of anionic ligands toward transition metal centers in low d-electron counts. The new LDPs do not correlate well to the pK(a) value of X. Conversely, the LDP values of phenoxide ligands do correlate with Hammett parameters for the para-substituents. Literature data for (13)C NMR chemical shifts for a tungsten-based system with various X ligands plotted versus LDP provided a linear fit. In addition, the angular overlap model derived e(σ) + e(π) values for chromium(III) ammine complexes correlate with LDP values. Also discussed is the correlation with XTiCp*(2) spectroscopic data. X-ray diffraction has been used used to characterize 31 of the compounds. From the X-ray diffraction data, steric parameters for the ligands using the Percent Buried Volume and Solid Angle techniques were found.