Rapid and Practical Synthesis of gem-Dibromoalkanes from Aldehydes by Tribromide Reagent.

gem-Dibromoalkanes are important synthetic building block in organic chemistry, but their preparation is still troublesome. Herein, we have developed a simple and practical protocol for the synthesis of gem-dibromoalkanes from aldehydes using tetrabutylammonium tribromide and triphenyl phosphite. A variety of alkyl and aromatic aldehydes can be transformed into the corresponding products within 10 minutes.

Recent advances of aminoazanium salts as amination reagents in organic synthesis.

Nitrogen-containing organic compounds are widely distributed in natural products, pharmaceuticals, and functional materials. Several methods have been reported for the construction of the C-N bond including the Curtius rearrangement, the Schmidt rearrangement, the Ullmann reaction, . Various sources of amines have been developed, among which the aminoazanium salt is a unique amine precursor because of its high operability, diversity of structures and diverse reaction modes.

Monopolar versus bipolar transurethral resection of bladder tumors: An updated systematic review and meta-analysis of existing studies.

Background: To compare the efficacy and safety of bipolar and monopolar transurethral resection of bladder tumors (TURBT) in non-muscle invasive bladder cancer (NMIBC) treatment.

Methods: This protocol established in this study has been reported following the preferred reporting items for systematic review and meta-analysis protocols. Web of Science, PubMed, EMBASE, and the Cochrane Library were searched for all randomized controlled trials comparing bipolar TURBT and monopolar TURBT in NMIBC treatment until 31st of June 2020.

Stereoselective Synthesis of Trisubstituted Vinylboronates from Ketone Enolates Triggered by 1,3-Metalate Rearrangement of Lithium Enolates.

An unprecedented stereoselective synthesis of trisubstituted vinylboronates is reported to proceed by direct borylation of lithium ketone enolates under transition-metal-free conditions. The stereospecific C-O borylation of lithium enolates was triggered by a carbonyl-induced 1,3-metalate rearrangement via a C-bound boron enolate. DFT calculations and control experiments revealed that the stereoselectivity is controlled by sterics.

Role of drinking water biofilms on residual chlorine decay and trihalomethane formation: An experimental and modeling study.

PVC pipe loops were constructed to simulate household premise plumbing. These pipe loops were exposed to water treated by physical processes at three water treatment plants in Xiamen, China from August 2016 to June 2017. After the biofilms were allowed to develop inside the pipes, these pipes were deconstructed and exposed to organic-free chlorine solution buffered at pH 6.

N-Heterocyclic carbene copper-catalyzed direct alkylation of terminal alkynes with non-activated alkyl triflates.

(NHC)-Cu-catalyzed C(sp)-C(sp) bond formation has been successfully achieved under mild conditions. Nonactivated alkyl triflates, which could be easily derived from alcohols, were utilized as C-O electrophiles. Mechanistic studies suggested that copper acetylide was the active species.

The reproductive health indices and sex hormone levels in middle-aged and elderly Chinese men.

Objective: The aim of this study was to analyze the age-related recession trajectory of reproductive health indices in middle-aged and elderly Chinese men.

Methods: A population-based cross-sectional study was conducted in Jiashan County, Zhejiang in 2012. Healthy men between 40 and 80 years of age were considered eligible for the study.