The cyclization-carbonylation-cyclization coupling reaction (CCC-coupling reaction) of propargyl ureas catalyzed by Pd(II)(box) complexes afforded symmetrical ketones bearing two 2-amino-2-oxazoline groups in good to moderate yields.

Stabilization of an enzyme while maintaining its activity has been a major challenge in protein chemistry. Although it is difficult to simultaneously improve stability and activity of a protein by amino acid substitutions due to the activity-stability trade-off, backbone cyclization by connecting the N and C termini with a linker is promising as a general method of stabilizing a protein without...

Enzymes catalyze reactions with exceptional selectivity and rate acceleration but are often limited by instability. Towards a generic route to thermo-resilience, we established the SpyRing approach, cyclizing enzymes by sandwiching between SpyTag and SpyCatcher (peptide and protein partners which lock together via a spontaneous isopeptide bond). Here we first investigated the basis for this res...

Cavities formed using cyclic tetrapeptides (CTPs) or heat-induced conformers act as templates for cyclization; the cavities bind to linear tetrapeptides and enforce turn conformations to enhance cyclization to constrained CTPs.

Selective transformation of 2-propargylthio-6-methyl-pyrimidin-4(1H)On e (2) to 3,5-dimethyl-7H-thiazolo [3,2-a] pyrimidin-7-one (3) is performed under the conditionof base catalysis . For elucidation of structure, palladium catalyzed cyclization reaction of (2) was carried out and the structures of the products were assigned (5) and (6). These compounds underwent isomerization to (3) and (4...

The product template (PT) domains, specifically in fungal non-reducing polyketide synthases (NR-PKSs), mediate the regioselective cyclization of polyketides dominating the final structures. However, up to date, the systematic knowledge about PT domains has been insufficient. In present study, the relationships between sequences, structures and functions of the PT domains were analyzed with 661 ...

[reaction: see text]Cyclization of the optically active ketone N,N-dialkyl aminals A affords the diastereomer B as the major product with diastereoselectivities ranging from nearly 1:1 to essentially 100:0 depending on the cyclization studied.

The 5-endo-trig-type cyclization has been performed using a Pd-bis(isoxazoline) catalyst. The present cyclization of β,γ-unsaturated carbonyl compounds gave γ-butenolides and 3-pyrrolin-2-ones in good to excellent yields.

This study reports a new photochemical cyclization of tetrafluoropyridinyl (TFP)-substituted enediynes that is accompanied with four formal hydrogen-atom abstractions from organic substrates and is mechanistically different from the Bergman cyclization.

reaction of 2-hydrazinocarbonyl-3-chloro-5-phenoxy-benzo[b] thiophene with different substituted phenyl isothiocyanate gave n-substituted arylthiosemi-carbazide derivatives (1a-h). 1,3,4-thiadiazole derivatives (2a-h) were prepared by the cyclization of arylthiosemicarbazides (1a-h) with concentrated sulphuric acid. all the compounds were screened for their antitubercular activity against mycob...