Discovery of bimodal hepatitis B virus ribonuclease H and capsid assembly inhibitors.

Hepatitis B virus (HBV) ribonuclease H (RNaseH) inhibitors are a potent class of antivirals that prevent degradation of the viral pregenomic RNA during reverse transcription and block formation of mature HBV DNAs. Development of HBV RNaseH inhibitors is entering advanced preclinical analyses. To ensure the mechanism of action was fully understood, we defined the effects of RNaseH inhibitors on other steps of HBV replication.

Discovery of an Orally Efficacious Pyrazolo[3,4-]pyrimidine Benzoxaborole as a Potent Inhibitor of .

Cryptosporidiosis is a diarrheal disease caused by the parasite resulting in over 100,000 deaths annually. Here, we present a structure-activity relationship study of the benzoic acid position (R) of pyrazolo[3,4-]pyrimidine lead SLU-2815 (), an inhibitor of parasite phosphodiesterase PDE1, resulting in the discovery of benzoxaborole SLU-10906 () as a benzoic acid bioisostere. Benzoxaborole is 10-fold more potent than against the parasite in a cell-based infection model (EC = 0.

Efficient Inhibition of Hepatitis B Virus (HBV) Replication and cccDNA Formation by HBV Ribonuclease H Inhibitors during Infection.

The hepatitis B virus (HBV) ribonuclease H (RNase H) is an attractive but unexploited drug target. Here, we addressed three limitations to the current state of RNase H inhibitor development: (a) Efficacy has been assessed only in transfected cell lines. (b) Cytotoxicity data are from transformed cell lines rather than primary cells.

Synthesis of Imide and Amine Derivatives via Deoxyamination of Alcohols Using -Haloimides and Triphenylphosphine.

A deoxyamination methodology of activated and unactivated alcohols is presented. The reaction is mediated by phosphonium intermediates generated from -haloimides and triphenylphosphine. The protocol allows for the synthesis of phthalimide and amine derivatives in moderate to good yields at room temperature.

Superelectrophilic carbocations: preparation and reactions of a substrate with six ionizable groups.

A substrate has been prepared having two triarylmethanol centers and four pyridine-type substituent groups. Upon ionization in the Brønsted superacid CFSOH, the substrate undergoes two types of reactions. In the presence of only the superacid, the highly ionized intermediate(s) provide a double cyclization product having two pyrido[1,2-]indole rings.

Regioselective α-Amination of Ethers Using Stable N-Chloroimides and Lithium tert-Butoxide.

Herein we describe a metal-free regioselective α-amination of ethers mediated by N-chloroimides in ethereal solvents in the presence of lithium tert-butoxide. This reactivity of N-chloroimides leads to the synthesis of hemiaminal ethers in good to excellent yields at room temperature. This C-H functionalization is achieved without the use of a light, heat source, or external radical initiators.

Synthesis of Heterocycle-Containing 9,9-Diarylfluorenes Using Superelectrophiles.

A superacid-promoted method for the synthesis of 9,9-diarylfluorenes is described. The chemistry involves cyclizations and arylations with biphenyl-substituted heterocyclic ketones and a mechanism is proposed involving superelectrophilic intermediates. The key reactive intermediates-dicationic and trication fluorenyl cations have been observed by low-temperature NMR and the mechanism has been further studied using DFT calculations.

Use of Charge-Charge Repulsion to Enhance π-Electron Delocalization into Anti-Aromatic and Aromatic Systems.

A series of 9-fluorenyl cations has been studied and it is shown that increasing charge on a heterocyclic substituent group enhances the anti-aromatic character of the carbocation system. Similarly, a series of dibenzosuberenyl cations has been studied and increasing charge on a substituent group is shown to enhance aromatic character in the carbocation system. These studies include the direct observations of dicationic and tricationic species using stable-ion conditions and low temperature NMR.

Tetra- and Pentacationic Electrophiles and Their Chemistry.

A tetracationic electrophile has been generated in superacid and shown to undergo an arylation reaction with benzene. A cyclization product is also obtained in the absence of benzene, presumably from a tricationic intermediate. Using low-temperature NMR, the tetracationic species is directly observed from a FSOH-SbF-SOClF solution.

Intramolecular Conjugate Additions with Heterocyclic Olefins.

The intramolecular reactions of olefinic N-heterocycles have been studied. In triflic acid-promoted reactions, conjugate addition is observed with pyrazine-, 2-pyrimidine-, and 2-quinoxaline-based olefins and a phenyl group nucleophile. Markovnikov addition is observed with pyridine and 5-quinoxaline-based olefins.