A highly enantioselective intramolecular Stetter reaction of aromatic and aliphatic aldehydes tethered to different Michael acceptors has been developed. Two triazolium scaffolds have been identified that catalyze the intramolecular Stetter reaction with good reactivity and enantioselectivity. The substrate scope has been examined and found to be broad; both electron-rich and -poor aromatic ald...

3.1. Other Salvinorins 1735 3.2. Role of the 2-Position Acetyl Group 1735 3.2.1. Ester Modifications 1735 3.2.2. Carbamate and Carbonate Analogs 1737 3.2.3. Ether and Amine Analogs 1737 3.2.4. Amides and Thioesters 1738 3.2.5. Sulfonyl Esters 1738 3.3. Other A Ring Changes 1738 3.4. Role of the 4-Position Carbomethoxy Group 1739 3.5. Role of the 17-Position Carbonyl 1739 3.6. Role of the Furan ...

Cholinesterase (ChE) enzymes have been identified as diagnostic markers for Alzheimer disease (AD). Substrate-based probes synthesised to detect ChEs but they not detected changes in ChE distribution associated with AD pathology. Probes are typically screened using spectrophotometric methods pure enzyme specificity and kinetics. However, the biochemical properties of pathology altered. The pres...

Proteins containing a C-terminal thioester are important intermediates in semisynthesis. Currently there is one main method for the synthesis of protein thioesters that relies upon the use of engineered inteins. Here we report a simple strategy, utilizing sortase A, for routine preparation of recombinant proteins containing a C-terminal (α)thioester. We used our method to prepare two different ...

Peptide-thioester is a pivotal intermediate for peptide ligation and N-, C-terminal cyclization. In this study, desired pathway and the side products of two C-terminal handles, hydroxyethylthiol (HET) and hydroxypropylthiol (HPT) are described in different conditions as well as kinetic studies. In addition, a new mechanism of C-terminal residue racemization is proposed on the basis of different...

2-Diazo-3,3,3-trifluoropropionyl chloride has been synthesized from trifluorodiazoethane and phosgene. Its derivatives are acid stable, can be used to label enzymes, and undergo photolysis with substantially less rearrangement than do derivatives of other known diazoacyl reagents designed for photoaffinity labeling. In particular, the diazotrifluoropropionyl thioester of methyl N-acetylcysteine...