Biocompatible synthesis of macrocyclic thiazole peptides from chiral α-amino nitriles.

Macrocyclic peptides containing a thiazole heterocycle exhibit fascinating properties in natural products and future therapeutics. We report a biocompatible macrocyclisation approach facilitated by an N-terminal cysteine and C-terminal nitriles. The use of various chiral α-amino nitriles enables the incorporation of diverse hydrophobic side chains adjacent to the thiazole motif.

Phage-encoded bismuth bicycles enable instant access to targeted bioactive peptides.

Genetically encoded libraries play a crucial role in discovering structurally rigid, high-affinity macrocyclic peptide ligands for therapeutic applications. Bicyclic peptides with metal centres like bismuth were recently developed as a new type of constrained peptide with notable affinity, stability and membrane permeability. This study represents the genetic encoding of peptide-bismuth and peptide-arsenic bicycles in phage display.

Novel Sulfonylurea Derivatives as Potential Antimicrobial Agents: Chemical Synthesis, Biological Evaluation, and Computational Study.

Methicillin-resistant (MRSA) is a worldwide health threat and has already tormented humanity during its long history, creating an urgent need for the development of new classes of antibacterial agents. In this study, twenty-one novel sulfonylurea derivatives containing phenyl-5-vinyl and pyrimidinyl-4-aryl moieties were designed and synthesized, among which, nine compounds exhibited inhibitory potencies against Gram-positive bacterial strains: MRSA (Chaoyang clinical isolates), ATCC6538, vancomycin-resistant -309 (VRE-309), and ATCC 6633. Especially, and demonstrated inhibitory activities against the four bacterial strains with minimum inhibitory concentrations (MICs) of 0.

Facile synthesis, crystal structure, quantum calculation, and biological evaluations of novel selenenyl sulfide compounds as potential agrochemicals.

Background: In order to design compounds with fresh molecular skeleton to break through the limitation of available agrochemicals, a series of 36 novel selenenyl sulfide compounds were chemically synthesized, and their biological activities were fully evaluated against tobacco mosaic virus (TMV), 14 plant pathogenic fungi, three insect species and plant acetohydroxyacid synthase (AHAS).

Results: All the target compounds were characterized by proton nuclear magnetic resonance ( H-NMR), carbon-13 ( C)-NMR, selenium-77 ( Se)-NMR, and high-resolution mass spectrometry (HRMS). The crystal structure of 10j indicated that the Se-S bond was successfully constructed.

Chemical preparation, degradation analysis, computational docking and biological activities of novel sulfonylureas with 2,5-disubstituted groups.

Based on the previous finding that a substitution at 5-position of the benzene ring is favorable to enhance the degradation rates of sulfonylurea herbicides, a total of 16 novel 2,5-disubsituted sulfonylurea compounds were chemically synthesized and fully characterized by means of H NMR, C NMR, HRMS and X-ray diffraction. By using HPLC analysis, the degradation behavior of M03, a compound belonging to this family, was studied and confirmed that chlorsulfuron itself is not a degraded product of the 2,5-disubstituted sulfonylureas. Inhibition constants against plant acetohydroxyacid synthase (AHAS) were determined for selected compounds, among which SU3 showed seven times stronger activity against the mutant W574L enzyme than chlorsulfuron.

Chemical synthesis, biological activities, and molecular simulations of novel sulfonylurea compounds bearing ortho-alkoxy substitutions.

A series of 51 novel sulfonylurea compounds with ortho-alkoxy substituent at phenyl ring were chemically synthesized and spectroscopically characterized. The biological activities of the target compounds were evaluated using the enzyme inhibition against acetohydroxyacid synthase (AHAS; EC 2.2.

Observation of frequency-uncorrelated photon pairs generated by counter-propagating spontaneous parametric down-conversion.

We report the generation of frequency-uncorrelated photon pairs from counter-propagating spontaneous parametric down-conversion in a periodically-poled KTP waveguide. The joint spectral intensity of photon pairs is characterized by measuring the corresponding stimulated process, namely, the difference frequency generation process. The experimental result shows a clear uncorrelated joint spectrum, where the backward-propagating photon has a narrow bandwidth of 7.