Iodine-promoted amide formation oxidative cleavage of indoles: novel quinazoline-4(3)-one and tryptanthrin syntheses.

A highly efficient method for the direct construction of amide bonds a selective cleavage of C-H and C[double bond, length as m-dash]C bonds in indole structures using an iodine-promoted approach was developed. Mechanistic studies indicated the formation of superoxide radicals obtained from molecular oxygen activation as a key intermediate step, which provided a precursor for subsequent oxidative ring-opening and intermolecular cyclization. A broad range of quinazolin-4(3)-ones and tryptanthrins were synthesized in moderate to good yields under mild and environmentally benign conditions.

DFT approach towards accurate prediction of H/C NMR chemical shifts for dipterocarpol oxime.

A computational NMR approach for accurate predicting the H/C chemical shifts of triterpenoid oximes featuring the screening of 144 DFT methods was demonstrated. Efficiently synthesized dipterocarpol oxime was employed as a model compound. The six highest accurate methods from the screening generated root-mean-square-error (RMSE) values in the range of 0.

Prevalence of mobile colistin resistance (mcr) genes in extended-spectrum β-lactamase-producing Escherichia coli isolated from retail raw foods in Nha Trang, Vietnam.

The aim of the study was to assess the presence of genes in ESBL-producing E. coli (ESBL-Ec) isolated from retail raw food in Nha Trang, Vietnam. A total of 452 food samples comprising chicken (n = 116), pork (n = 112), fish (n = 112) and shrimp (n = 112) collected between 2015 and 2017 were examined for the prevalence of ESBL-Ec.

Catalytic allylic oxidation of internal alkenes to a multifunctional chiral building block.

The stereoselective oxidation of hydrocarbons is one of the most notable advances in synthetic chemistry over the past fifty years. Inspired by nature, enantioselective dihydroxylations, epoxidations and other oxidations of unsaturated hydrocarbons have been developed. More recently, the catalytic enantioselective allylic carbon-hydrogen oxidation of alkenes has streamlined the production of pharmaceuticals, natural products, fine chemicals and other functional materials.

Hydrazone-initiated carbene/alkyne cascades to form polycyclic products: ring-fused cyclopropenes as mechanistic intermediates.

A hydrazone-based carbene/alkyne cascade produced a variety of bridged and fused polycyclic products. NaOSiMe3 is a superior base for conversion of hydrazones to diazoalkanes. A key mechanistic intermediate, a ring-fused cyclopropene, has been isolated and characterized.

A general method for the enantioselective synthesis of α-chiral heterocycles.

The enantioselective formation of stereocenters proximal to unprotected heterocycles has been accomplished. Thus, vinyl boronic acids are added to heterocycle-appended enones via a modified-BINOL catalyst. Catalyst design was key to enable a general reaction.