Pradefovir: A Prodrug That Targets Adefovir to the Liver for the Treatment of Hepatitis B
摘要:
Adefovir dipivoxil, a marketed drug for the treatment of hepatitis B, is dosed at submaximally efficacious doses because of renal toxicity. In an effort to improve the therapeutic index of adefovir, 1-aryl-1,3-propanyl prodrugs were synthesized with the rationale that this selectively liver-activated prodrug class would enhance liver levels of the active metabolite adefovir diphosphate (ADV-DP) and/or decrease kidney exposure. The lead prodrug (14, MB06866, pradefovir), identified from a variety of in vitro and in vivo assays, exhibited good oral bioavailability (F = 42%, mesylate salt, rat) and rate of prodrug conversion to ADV-DP. Tissue distribution studies in the rat using radiolabeled materials showed that cyclic 1-aryl-1,3-propanyl prodrugs enhance the delivery of adefovir and its metabolites to the liver, with pradefovir exhibiting a 12-fold improvement in the liver/kidney ratio over adefovir dipivoxil.
Studies on the chemoenzymatic synthesis of (R)- and (S)-methyl 3-aryl-3-hydroxypropionates: the influence of toluene-pretreatment of lipase preparations on enantioselective transesterifications
摘要:
Two series (para- and meta-substituted) of racemic methyl esters of 3-aryl-3-hydroxypropionic acid were prepared after which the enantiomers were separated by an enzyme-catalyzed transesterification. Several lipases were investigated as the catalyst. The influence of the enzyme pretreatment, as well as substrate concentration, reaction temperature, stirring manner, and substrate conversion on the stereochemical outcome of the biotransformation process were investigated in detail. The best results were achieved by using solvent-pretreated lipase from Pseudomonas fluorescens or Burkholderia cepacia suspended in toluene, and vinyl acetate as the acetyl group donor. (C) 2013 Elsevier Ltd. All rights reserved.
Inhibition of urease results in Helicobacter pylori growth arrest in the stomach, promoting urease as promising targets for gastrointestinal ulcer therapy. Twenty hybrid derivatives of flavonoid scaffold and hydroxamic acid, β-hydroxy-β-phenylpropionylhydroxamic acids, were therefore synthesized and evaluated against H. pylori urease. Biological evaluation of these compounds showed improved urease
hemimalonate used. With the unsubstituted substrate, a carboxylic acid intermediate was isolated upon acid quench resulting from the nucleophilic addition of the putative enol carboxylate anion of the hemimalonate to imines/aldehydes before CO2 loss. With substituted hemimalonates, the reaction likely involved an enolate which then added to imines/aldehydes or was competitively protonated. According to the base
Efficient Synthesis of β-CF<sub>3</sub>/SCF<sub>3</sub>-Substituted Carbonyls via Copper-Catalyzed Electrophilic Ring-Opening Cross-Coupling of Cyclopropanols
作者:Yong Li、Zhishi Ye、Tabitha M. Bellman、Teng Chi、Mingji Dai
DOI:10.1021/acs.orglett.5b00782
日期:2015.5.1
The first copper-catalyzed ring-opening electrophilic trifluoromethylation and trifluoromethylthiolation of cyclopropanols to form Csp3–CF3 and Csp3–SCF3 bonds have been realized. These transformations are efficient for the synthesis of β-CF3- and β-SCF3-substituted carbonyl compounds that are otherwise challenging to access. The reaction conditions are mild and tolerate a wide range of functional
An Umpolung Strategy for the Synthesis of β-Aminoketones via Copper-Catalyzed Electrophilic Amination of Cyclopropanols
作者:Zhishi Ye、Mingji Dai
DOI:10.1021/acs.orglett.5b00828
日期:2015.5.1
A novel copper-catalyzed electrophilic amination of cyclopropanols with O-benzoyl-N,N-dialkylhydroxylamines to synthesize various β-aminoketones via a sequence that includes C–C bond cleavage and Csp3–N bond formation is reported. The reaction conditions are mild and tolerate a wide range of functional groups including benzoate, tosylate, expoxide, and α,β-unsaturated carbonyls, which are incompatible
Optically active alkyl 3-aryl-3-hydroxypropionates and a method for producing thereof
申请人:CHISSO CORPORATION
公开号:EP0451668A2
公开(公告)日:1991-10-16
The invention relates to optically active alkyl 3-aryl-3-hydroxypropionates represented by the general formula:
wherein R¹, R², R³, R ⁴ and R⁵ are hydrogen, hydroxyl, alkoxy of 1-4 carbon atoms, benzyloxy, flurorine, chlorine or bromine and R⁶ is alkyl,
and a method for producing the above compounds.