Over four hundred alkaloids in amphibian skin have been detected and structures from twenty different classes have been elucidated. These include batrachotoxins, histrionicotoxins, pumiliotoxins, epibatidine, pyrrolidines, piperidines, decahydroquinolines, pyrrolizidines, indolizidines, quinolizidines and tricyclic gephyrotoxins, pyrrolizidine oximes, pseudophrynamines, coccinellines and cyclop...

A general chemo-enzymatic approach to synthesize both enantioenriched trans-3-alkoxyamino-4-oxy-2-piperidones, which are important scaffold for various naturally occurring alkaloids, is reported. To this end, a selective transition-metal-free dual C−H oxidation of piperidines mediated by the TEMPO oxoammonium cation (TEMPO+) was used, followed enzymatic resolution corresponding alkoxyamino-2-pi...

Piperazine ranks within the top three most utilized N-heterocyclic moieties in FDA-approved small-molecule pharmaceuticals. Herein we summarize the current synthetic methods available to perform C-H functionalization on piperazines in order to lend structural diversity to this privileged drug scaffold. Multiple approaches such as those involving α-lithiation trapping, transition-metal-catalyzed...

QSAR study describes the anti-neoplastic spiro-alkaloids with relevant molecular descriptors using CODESSA III software. The dispiro[3H-indole-3,2'-pyrrolidine-3',3"-piperidines] 24-48 were synthesized via [3 + 2]-cycloaddition reaction of azomethine ylides, (generated in situ via decarboxylative condensation of isatins 21-23 with sarcosine) and 3E,5E-1-alkyl-3,5-bis(arylmethylidene)-4-piperido...

This account focuses on the application of ω-transaminases, lyases, and oxidases for the preparation of amines considering mainly work from our own lab. Examples are given to access α-chiral primary amines from the corresponding ketones as well as terminal amines from primary alcohols via a two-step biocascade. 2,6-Disubstituted piperidines, as examples for secondary amines, are prepared by bio...

Polyand multifunctional piperidines isolated from microorganisms and plants are powerful and specific glycosidase inhibitors, and they have the potential to produce a number of kinds of beneficial therapeutic effects such as antihyperglycemic, antiviral and anticancer activity, etc. l) A multifunctional piperidine, siastatin B (1) which was isolated as an inhibitor of neuraminidase by H. Umezaw...

Neuropeptide FF1 and FF2 receptors (NPFF1-R and NPFF2-R), and their endogenous ligand NPFF, are one of only several systems responsible for mediating opioid-induced hyperalgesia, tolerance, and dependence. Currently, no small molecules displaying good affinity or selectivity for either subtype have been reported, to decipher the role of NPFF2-R as it relates to opioid-mediated analgesia, for fu...