2,396 research outputs found
A dinuclear zinc complex with (E)-4-dimethylÂamino-N′-(2-hyÂdroxyÂbenzylÂidene)benzohydrazide
The title compound, bisÂ[ÎĽ-(E)-2-({2-[4-(dimethylÂamino)ÂbenzoÂyl]hydrazinylÂidene}methÂyl)phenolato]bisÂ[formatoÂzinc], [Zn2(C16H16N3O2)2(CHO2)2], is a dinuclear ZnII complex containing two ZnII cations, two monovalent anions of a Schiff base ligand, 4-dimethylÂamino-N′-(2-hyÂdroxyÂbenzylÂidene)benzohydrazide (L), and two formate ions. Each ZnII atom chelates with the hyÂdroxy O atom of salicylÂaldehyde, the imine N atom, the carbonyl O atom, the formate carboxylÂate O atom and the hyÂdroxy O atom of the salicylÂaldehyde moiety in a symmetry-related unit. The five-coordinate ZnII atoms form a dimeric centrosymmetric unit with a central parallelepiped Zn2O2 core and parallel faces derived from the Schiff base ligands. The crystal packing is stabilized by interÂmolecular N—Hâ‹ŻO hydrogen bonds between the amide N atom and the formate carboxylÂate O atom
Lipase-catalyzed remote kinetic resolution of citalopram intermediate by asymmetric alcoholysis and thermodynamic analysis
Lipase-catalyzed remote resolution of the tertiary alcohol, citalopram intermediate (diol acetate), has been achieved. The chiral discrimination was obtained by the Novozym435-catalyzed alcoholysis of the primary hydroxyl ester which was four bonds away from the center. The influence of acyl acceptor structure and the organic solvents on the reaction rate and enantioselectivity were investigated. Based on the thermodynamic analysis, the difference of activation free energy between the two enantiomers which dominated the enantioselectivity was significantly affected by the organic solvents, while the acyl acceptor showed less effect. In addition, the enantiomer discrimination was driven by both the difference of activation enthalpy and activation entropy. The thermodynamic analysis provides further insights into the prediction and optimization of enantioselectivity and reaction rate in remote resolution.National Natural Science Foundation of China [20936002]; Key Project of Chinese National Programs for Fundamental Research and Development [2011CB710800]; Hi-Tech Research and Development Program of China [2011AA02A209
Outcomes and prognostic factors for patients with cervical esophageal cancer undergoing definitive radiotherapy or chemoradiotherapy
Cervical esophageal cancer (CEC) is uncommon, accounting for less than 5% of all esophageal cancers. The management of CEC is controversial. This study investigated treatment outcomes and prognostic factors of survival in CEC patients undergoing definitive radiotherapy or concurrent chemoradiotherapy (CCRT). Ninety-one CEC patients were treated by intensity-modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3DCRT) between July 2007 and September 2017. The mean prescription dose was 64 Gy (range 54-70 Gy) delivered as 1.8-2.2 Gy per fraction per day, 5 days a week. Out of 91 patients, 34 received concurrent cisplatin-based chemotherapy (CT) including 18 patients who also received neoadjuvant CT. Overall survival (OS), locoregional failure-free survival (LRFFS), and progression-free survival (PFS) were estimated by the Kaplan–Meier method. Prognostic factors of survival were determined in univariate (log-rank test) and multivariate (Cox proportional hazard model) analysis. Treatment-related toxicity was also assessed. Median follow-up time for all patients was 19 months. Two-year OS, LRFFS and PFS of all patients were 58.2%, 52.5% and 48.1%, respectively. Clinical stage was an independent prognostic factor for OS (HR = 2.35, 95% CI: 1.03-5.37, p = 0.042), LRFFS (HR = 3.84, 95% CI: 1.38-10.69, p = 0.011), and PFS (HR = 2.68, 95% CI: 1.11-6.45, p = 0.028). Hoarseness was an independent prognostic factor for OS (HR = 2.10, 95% CI: 1.05-4.19, p = 0.036). CCRT was independently associated with better LRFFS (HR = 0.33, 95% CI: 0.14-0.79, p = 0.012). 3DCRT and IMRT with concurrent CT is well-tolerated and may improve local tumor control in CEC patients. Advanced clinical stage and hoarseness are adverse prognostic factors for OS, LRFFS, and PFS in CEC
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