Drug-like spirocyclic scaffolds have been prepared by fusing fully functionalized pyrrolidine with oxindoles in an approach based on 1,3-dipolar cycloaddition. Reaction between aziridine and 3-ylideneoxindole generated diverse spirooxindole-pyrrolidines in good yield (up to 95%) with high diastereoselectivity (up to >20:1). The reaction also proceeded smoothly with several other synthetically u...

Bi(OTf)(3)·nH(2)O was found to be an efficient promoter of the cyclisative hydroamination of unactivated alkenyl sulfonamides, giving rise to the N-protected 2-methyl pyrrolidines in good to excellent yields (up to 95%). Based on control experiments, a joint Lewis acid-Brønsted acid catalysis might be in operation, or triflic acid itself, generated in situ by hydrolysis of metal triflate, could...

A new method to rapidly generate pyrrolidines via a SOMO-activated enantioselective (3 + 2) coupling of aldehydes and conjugated olefins has been accomplished. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnish a cationic intermediate which is vulnerable to nucleophilic addition of a tether...

A diverse array of biologically active, lipid-soluble alkaloids have been discovered in amphibian skin. Such alkaloids include the following: the steroidal samandarines from salamanders, the batrachotoxins, histrionicotoxins, gephyrotoxins, and epibatidine from neotropical poison frogs (Dendrobatidae), the pumiliotoxins, allopumiliotoxins, homopumiliotoxins, and decahydroquinolines from certain...

One-pot, four-component procedure for the synthesis of a small library of new chiral spiro- oxindolopyrrolidines with high regio-, diastereo- (>99:1 dr), and enantioselectivity (up to 80% ee) is described. In this process, the regio- and stereochemical 1,3-dipolar cycloaddition of azomethine ylides, which were generated insitu by the reaction of isatin derivatives and sarcosin,with optically ac...

In the first part of this work, correlation between optical activity and elements of magnetic susceptibility tensor (MST) for five classes of model small molecules containing a single chiral center has been studied using quantum computational techniques at DFT-B3LYP level of theory with 6-311G basis set. Several molecular properties are used to reduce the MST elements prior to the examination o...

   In chiral and non-chiral electrophoretic resolution of basic drugs, adsorption of analytes to negatively charged capillary wall could lead to poor repeatability of migration time and peak area. In addition, chiral resolutions of basic drugs are commonly performed in low pH buffers. Therefore, longer analysis time due to suppression of electroosmotic flow (EOF) is another dilemma. In this wor...

A number of novel spiro-pyrrolidines/pyrrolizines derivatives were synthesized through [3+2]-cycloaddition of azomethine ylides with 3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones 2a-n. Azomethine ylides were generated in situ from the reaction of 1H-indole-2,3-dione (isatin, 3) with N-methylglycine (sarcosine), phenylglycine, or proline. All compounds (50 μM) were evaluated for their...