Cobalt-Catalyzed Chemoselective Transfer Hydrogenative Cyclization Cascade of Enone-Tethered Aldehydes.

The ligand-free Co-catalyzed chemoselective reductive cyclization cascade of enone-tethered aldehydes with -PrOH as the environmentally benign hydrogen surrogate is developed by this study. Mechanistic studies disclosed that such a protocol is initiated by an -enone-assisted Co(I)-catalyzed reduction of the aldehyde functionality with -PrOH. Meanwhile, the selectivity from the Michael-Aldol cycloreduction cascade to the oxa-Michael cascade is feasible and readily adjusted by the addition of steric Lewis bases, such as TEMPO and DABCO, delivering substituted 1-indenes and dihydroisobenzofurans, respectively.

Dehydrative Formation of Isosorbide from Sorbitol over Poly(ionic liquid)-Covalent Organic Framework Hybrids.

In this study, the covalent bonding of linear poly(ionic liquid)s (PILs) with covalent organic frameworks (COFs) was accessed by copolymerization of a vinyl-decorated COF with 4-vinylbenzyl chloride, followed by quaternization with tertiary amines. The resultant PIL-COF composite by anchoring a proper content of vinyl sites on the COF-based comonomer retains the crystallinity and porosity, thereby facilitating access of the reactants to the catalytic active sites. As a proof of concept, the dehydrative transformation of sorbitol into isosorbide was selected as a benchmark reaction, whose rate improved significantly in the presence of PIL-COF-0.

Boosting the hole transport of conductive polymers by regulating the ion ratio in ionic liquid additives.

Poly(3,4-ethylenedioxythiophene) (PEDOT) has aroused great interest in organic electrics because of its high electrical conductivity and mechanical flexibility. To improve the charge transport, it can act as an ionic liquid (IL) additive due to its ion characteristics and high electrical conductivity. Herein, we investigated the hole-transport performance of PEDOT treated by ILs featuring specific ion ratios (4 : 1, 3 : 1, 2 : 1, 1 : 1, 1 : 2, 1 : 3, and 1 : 4) of the cation and anion through classical dynamics simulations and quantum mechanics computations.

Tris(pyrazolyl)borate Cobalt-Catalyzed Hydrogenation of C═O, C═C, and C═N Bonds: An Assistant Role of a Lewis Base.

The combination of tris(pyrazolyl)borate cobalt complexes and Lewis base is developed as an efficient catalyst precursor in the homogeneous hydrogenation. A broad substrate scope including carbonyls, alkenes, enamines, and imines is reduced with 60 atm of H at 60 °C. Mechanistic studies support the hydrogenation operates through a frustrated Lewis pair (FLP)-like reduction process.

N-Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N-chlorosuccinimide.

The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated.

A metal-free direct C (sp)-H cyanation reaction with cyanobenziodoxolones.

A metal-free protocol of direct C(sp)-H cyanation with cyanobenziodoxolones functioning as both cyanating reagents and oxidants was developed. Unactivated substrates, such as alkanes, ethers and tertiary amines, were thereby transformed to the corresponding nitriles in moderate to high yields. Mechanistic studies indicated that the cyanation proceeded with two potential pathways, which is highly dependent on the substrates: (1) a free radical case for alkanes and ethers and (2) an oxidative case for tertiary amines.

Oxidation of Aromatic Aldehydes to Esters: A Sulfate Radical Redox System.

A mild oxidative esterification of various aromatic aldehydes by sulfate radical redox system was presented. In the reaction pathway exploration, the transiency of MeOSO was disclosed, which was generated from esterification between the in situ generated HSO and MeOH, a rate-limiting step in the process. More importantly, the selectivity-controlling step was represented by the subsequent nucleophilic displacement between MeOSO and aldehydes.

Experimental and theoretical studies on hydrogen bond-promoted fixation of carbon dioxide and epoxides in cyclic carbonates.

The hydrogen bond donor-promoted fixation of CO(2) and epoxides into cyclic carbonates was investigated through experimental and density functional theory studies. A highly effective homogeneous system of 1,2-benzenediol-tetrabutyl ammonium bromide (TBAB) and heterogeneous poly-ionic liquids were developed for the fixation of CO(2) into cyclic carbonates via hydrogen bond activation, based on the understanding of the reaction mechanism and catalyst design. The work hence provides a molecular level understanding of the reaction process and forms the basis for the rational design of catalytic systems for the fixation of CO(2) into useful organic compounds.

Synthesis of bimagnetic ionic liquid and application for selective aerobic oxidation of aromatic alcohols under mild conditions.

The first bimagnetic ionic liquid based on Fe and TEMPO with cooperative functionalities not only exhibited strong paramagnetic behaviour at room temperature under an applied magnetic field of 5000 Oe but also proved to be an effective catalyst for selective aerobic oxidation of aromatic alcohols under mild and clean conditions.

[Clinicopathologic study on 61 cases of uterine papillary serous carcinoma with or without adjuvant therapy].

Objective: To study the clinicopathologic features of uterine papillary serous carcinoma (UPSC) and the roles of adjuvant therapy.

Methods: Sixty-one cases of UPSC with operation done and followed up for a period of 4 to 9 years were enrolled into the study. The histology of slides specimens were reviewed and immunohistochemical study was performed.

[Clonality analysis and mutational status of IgVH gene in Hodgkin variant of Richter syndrome].

Objective: To detect the clonal relationship, the rearrangement, and the mutational status of IgVH gene; the influence of these molecular characteristics on the clinical outcome in Hodgkin variant of Richter syndrome; and the possible molecular pathogenesis in this transformation.

Methods: The clonal rearrangements and mutational status of IgVH genes were analyzed in Hodgkin variant of Richter syndrome and B-CLL with Reed-Stemberg (R-S)-like cells by GeneScan analysis and sequencing. Semi-nest PCR based on laser capture microdissection was utilized to compare the clonal relationship between B-CLL and R-S/R-Slike cells.

[Clonality analysis and mutation status of IgVH genes in classic Richter's syndrome].

Objective: To study the clonal rearrangements and mutation status of IgVH genes in classic Richter's syndrome, the relationship between molecular findings of IgVH gene and clinical outcome, and to deciper the possible molecular mechanism of transformation.

Methods: The clonal rearrangements and mutation status of IgVH genes were analyzed in cases of classic Richter's syndrome by Genescan and sequencing. Immunohistochemical study for zeta-chain associated protein kinase 70 kDa (ZAP70), p53 and interferon regulation factor 4 (IRF-4) was also performed.

[Study of dual rearrangements of lymphocytic antigen receptor genes in non-Hodgkin lymphoma].

Objective: To investigate the rate of dual rearrangements of lymphocytic antigen receptor genes in non-Hodgkin lymphomas (NHL) and its pathogenesis and pathologic significance.

Methods: PCR analysis of monoclonal, polyclonal and dual rearrangements of IgH and TCR gamma, TCR beta genes was carried out in 125 cases of NHL to evaluate the rate of dual rearrangements, immunohistochemistry was performed for a Ki67 protein expression in 117 cases and the proliferation index was calculated. The relationship between antigen receptor gene rearrangements and proliferation index was analyzed.

[Analysis of autopsy cases in 50 years].

Objective: To evaluate the changing rate for autopsy and the reason during 50 years, and to study the disagreement between pathological and clinical diagnosis in 3162 autopsy cases.

Methods: To retrospectively analyses 3162 autopsy cases in School of Medicine of Zhejiang University from 1950 to 1999.

Results: (1) The most autopsy cases is 1037 cases during 1960 - 1970, while the lowest is 102 cases during 1990 - 1999.

[Effects of power frequency magnetic field on gap junction intercellular communication of astrocytes].

Objective: In order to explore if power frequency magnetic field (PFMF) can act as cancer promoter or be synergistic with phorbol 12-myristate 13-acetate (TPA) in cancer promotion, the effects of 50 Hz MF on gap junction intercellular communication (GJIC) of astrocytes were observed.

Methods: Fluorescence redistribution after photobleaching (FRAP) was adopted to observe the recovery of fluorescence intensity in the bleached cells thus to estimate intercellular communication by gap junction. Comparative fluorescence intensity recovery rate (CFIRR) was as evaluation index.

Involvement of ATM/ATR-p38 MAPK cascade in MNNG induced G1-S arrest.

Aim: To understand the effect of low concentration of N-methyl-N'-nitro-nitrosoguanidine (MNNG), which is a widely distributed environmental mutagen and carcinogen especially for human gastric cancer, on DNA damage and to study its possible pathway in regulating cell cycle arrest.

Methods: The DNA damage effect was measured by Comet assay. A specific phospho-(Ser/Thr) ATM/ATR substrate antibody was used to detect the damage sensor by Western blot.