Hypervalent-Iodine-Mediated Formation of Epoxides from Carbon(sp2)-Carbon(sp3) Single Bonds.

We have developed an efficient method for direct formation of epoxide groups from carbon(sp2)-carbon(sp3) single bonds of ß-keto esters; the reaction is mediated by the water-soluble hypervalent iodine(V) reagent AIBX (5-trimethylammonio-1,3-dioxo-1,3-dihydro-1λ5-benzo[d][1,2]iodoxol-1-ol anion). On the basis of the results of density functional theory calculations and experimental studies, we propose that the reaction proceeds by a two-stage mechanism involving dehydrogenation of the ß-keto ester substrates and epoxidation of the resulting enone intermediates. The rate-limiting step is abstraction of the ß'-C-H (calculated free energy of activation, 24.5 kcal/mol).

Recyclable Hypervalent-Iodine-Mediated Dehydrogenative α,ß'-Bifunctionalization of ß-Keto Esters Under Metal-Free Conditions.

We have developed a method for recyclable hypervalent-iodine-mediated direct dehydrogenative α,ß'- bifunctionalization of ß-ketoesters and ß-diketones under metal-free conditions, which affords a straightforward way to synthesize benzo-fused 2,3-dihydrofurans. This efficient, mild method, which has a wide substrate scope and good functional-group tolerance, was used for the multistep synthesis of the protected aglycone of a naturally occurring phenolic glycoside. A mechanism involving Michael addition to an enone intermediate and subsequent oxidative cyclization is proposed.

Design, synthesis, structure, and dehydrogenation reactivity of a water-soluble o-iodoxybenzoic acid derivative bearing a trimethylammonium group.

5-Trimethylammonio-1,3-dioxo-1,3-dihydro-1λ(5)-benzo[d][1,2]iodoxol-1-ol anion (AIBX 1a), an o-iodoxybenzoic acid (IBX) derivative having the trimethylammonium moiety on its phenyl ring, possesses very good solubility in water and distinct oxidative properties from IBX, which is demonstrated in the oxidation of various ß-keto esters to the corresponding dehydrogenated products using water as cosolvent. The regeneration of AIBX 1a can be easily realized from the reaction mixture due to its good water solubility.

Effective oxidation of benzylic and alkane C-H bonds catalyzed by sodium o-iodobenzenesulfonate with Oxone as a terminal oxidant under phase-transfer conditions.

Catalytic oxidation of benzylic C-H bonds could be efficiently realized using IBS as a catalyst which was generated in situ from the oxidation of sodium 2-iodobenzenesulfonate (1b) by Oxone in the presence of a phase-transfer catalyst, tetra-n-butylammonium hydrogen sulfate, in anhydrous acetonitrile at 60 °C. Various alkylbenzenes, including toluenes and ethylbenzenes, several oxygen-containing functionalities substituted alkylbenzenes, and a cyclic benzyl ether could be efficiently oxidized. And, the same reagent system of cat. 1b/Oxone/cat. n-Bu(4)NHSO(4) could be applied to the effective oxidation of alkanes as well.

[A comparative study of voxel-based morphometry in patients with paranoid schizophrenia and bipolar mania].

OBJECTIVE: To assess volumetric abnormalities of grey matter in the brains of patients with paranoid schizophrenia and bipolar disorder (mania). METHODS: 3D T1 weighted images were acquired by magnetic resonance imaging from 20 patients with paranoid schizophrenia, 20 patients with bipolar disorder (mania) and 20 control subjects. Regional deviation in gray matter volume was assessed using optimized volumetric voxel-based morphometry. ANOVA was performed to test the difference of the gray matter volume (GMV). RESULTS: Compared with controls, the patients with paranoid schizophrenia showed decreased gray matter volume in left superior temporal gyrus, right middle temporal gyrus and inferior temporal gyrus, and increased gray matter volume in bilateral inferior frontal gyrus and bilateral claustrum. Whereas, the patients with bipolar disorder (mania) showed decreased gray matter volume in right superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus and bilateral caudate, and increased gray matter volume in bilateral precuneus, left postcentral gyrus, right superior frontal gyrus and left cingulated gyrus. The patients with paranoid schizophrenic patients had greater gray matter volume in left inferior frontal gyrus, left superior temporal gyrus and right caudate than the patients with bipolar disorder. CONCLUSION: Patients with schizophrenic and bipolar disorder have different changes in brain structure. However, they also share the same reduction of GDV in right temporal gyrus.

[Brain structure abnormality as genetic endophenotype of schizophrenia].

OBJECTIVE: To explore the role of genetic factors in the brain structural variation by using magnetic resonance imaging scan in schizophrenic patients and their unaffected siblings, and to provide experimental evidence for identifying endophenotype of schizophrenia. METHODS: The optimized voxel-based morphometry (OVBM) was used to process the brain magnetic resonance images in 15 first episode drug-naive schizophrenic patients, 19 unaffected siblings of the patients and 38 normal control subjects. The data were analyzed by using general linear model. RESULTS: Compared to the normal control subjects, significant decreases of gray matter was observed in first episode drug-naive schizophrenia in bilateral temporal lobe, bilateral occipital lobe, left insula, left frontal lobe superior frontal gyrus and right lentiform nucleus medial globus pallidus. Significant increases of gray matter in bilateral parietal lobe, bilateral limbic lobe cingulate gyrus in patients group while compared to controls were also found. In unaffected siblings, significant decreases of gray matter was observed in the right temporal lobe, bilateral occipital lobe, left insula, and left frontal lobe precentral gyrus, and significant increases of gray matter were found in left parietal lobe and bilateral cerebellum posterior lobe. Increased gray matter in left parietal lobe precuneus was found in first episode drug-naive schizophrenia when compared with their unaffected siblings. CONCLUSION: There were similar brain structure abnormalities between the first episode drug-naive schizophrenia and their unaffected siblings. Genetic factor may play important role in brain structural abnormality in schizophrenia, which suggested that the brain structural change might be a genetic endophenotype of schizophrenia.