(5S)-5-(Trifluoromethyl)pyrrolidin-2-one as a Promising Building Block for Fluoroorganic Chemistry

Synthesis, molecular docking studies, and larvicidal activity evaluation of new fluorinated neonicotinoids against Anopheles darlingi larvae

Anopheles darlingi is the main vector of malaria in Brazil, characterized by a high level of anthropophilia and endophagy. Imidacloprid, thiacloprid, and acetamiprid are the most widespread insecticides of the neonicotinoid group. However, they produce adverse effects on the non-target insects. Flupyradifurone has been marketed as an alternative to non-fluorinated neonicotinoids. Neonicotinoids containing trifluoroacethyl substituent reveal increased insecticidal activity due to higher hydrophobicity and metabolic stability. We synthesized novel neonicotinoid insecticides containing fluorinated acceptor groups and their interactions were estimated with the nicotinic acetylcholine receptor (nAChR) binding site by molecular docking studies, to evaluate their larvicidal activity against A. darlingi, and to assess their outdoor photodegradation behavior. New neonicotinoid analogues were prepared and characterized by NMR and mass-spectrometry. The synthesized molecules were modelled by time-dependent density functional theory and analyzed, their interaction with nAChR was investigated by molecular docking. Their insecticide activity was tested on Anopheles larvae collected in suburban area of Manaus, Brazil. Four new fluorinated neonicotinoid analogs were prepared and tested against 3rd instars larvae of A. darlingi showing high larvicidal activity. Docking studies reveal binding modes of the synthesized compounds and suggest that their insecticidal potency is governed by specific interactions with the receptor binding site and enhanced lipophilicity. 2-Chloro-5-(2-trifluoromethyl-pyrrolidin-1-ylmethyl)pyridine 5 showed fast degradation in water maintaining high larvicidal activity. All obtained substances possessed high larvicidal activity in low concentrations in 48 hours of exposure, compared to commercial flupyradifurone. Such activity is connected to a unique binding pattern of the synthesized compounds to insect's nAChR and to their enhanced bioavailability owing to introduction of fluorinated amino-moieties. Therefore, the compounds in question have a high potential for application as control agents for insects transmitting tropical diseases, and they will be less persistent in the environment.

Synthesis of Spirocyclic Pyrrolidines: Advanced Building Blocks for Drug Discovery

In the context of drug discovery, novel spirocyclic pyrrolidines have been synthesized in two steps from common three- to seven-membered-ring (hetero)alicyclic ketones. The key transformation is a reaction between an electron-deficient exocyclic alkene and an in situ generated N-benzyl azomethine ylide. The developed method has been used to synthesize the central diamine core of the known antibacterial agents Sitafloxacin and Olamufloxacin.

Stereoselective Ag-Catalyzed 1,3-Dipolar Cycloaddition of Activated Trifluoromethyl-Substituted Azomethine Ylides

A silver-catalyzed 1,3-dipolar cycloaddition of fluorinated azomethine ylides and activated olefins is reported. The reaction offers a straightforward and atom-economical procedure for the preparation of fluorinated pyrrolidines. Broad scope and high levels of diastereoselectivity have been achieved simply by using AgOAc/PPh3 as the catalyst system. The high efficiency of the cycloaddition relies on the presence of a metal-coordinating group on the imine moiety, such as an ester or heteroaryl group. The asymmetric version of the cycloaddition has been developed by using Taniaphos as a chiral ligand.

Trifluoromethyl nitrogen heterocycles: synthetic aspects and potential biological targets

The synthetic methodologies and the potential biological targets of α-trifluoromethylated nitrogen heterocycles are presented.

Asymmetric synthesis of functionalized trifluoromethyl-substituted pyrrolidines via an organocatalytic domino Michael/Mannich [3+2] cycloaddition

The asymmetric synthesis of highly functionalized pyrrolidine derivatives with three contiguous stereogenic centers and bearing a trifluoromethyl group has been developed through an organocatalytic domino Michael/Mannich [3+2] cycloaddition sequence.

Trisubstituted 2-trifluoromethyl pyrrolidines via catalytic asymmetric Michael addition/reductive cyclization

The stereoselective synthesis of trisubstituted 2-trifluoromethyl pyrrolidines by asymmetric Michael addition/hydrogenative cyclization is described. The direct organocatalytic addition of 1,1,1-trifluoromethylketones to nitroolefins proceeds under mild reaction conditions and low catalyst loadings to provide Michael adducts in high yield with excellent diastereo- and enantioselectivity. Catalytic hydrogenation of the Michael adducts stereoselectively generates 2-trifluoromethylated pyrrolidines bearing three contiguous stereocenters. A stereospecific route to epimeric 2-trifluoromethyl pyrrolidines from a common intermediate is described.

Selective synthesis of functionalized trifluoromethylated pyrrolidines, piperidines, and azepanes starting from 1-tosyl-2-(trifluoromethyl)aziridine

This paper reports on the generation and alkylation of the 1-tosyl-2-(trifluoromethyl)aziridin-2-yl anion with ω,ω'-dihaloalkanes, followed by a novel ring-expansion protocol toward 2-CF3-pyrrolidines, 2-CF3-piperidines, and 3-CF3-azepanes. A variety of halogen, oxygen, nitrogen, sulfur, and carbon nucleophiles was used to trigger this ring rearrangement, resulting in CF3-azaheterocycles bearing different types of functionalized side chains.