New methodology for 2-alkylation of 3-furoic acids: application to the synthesis of tethered UC-781/d4T bifunctional HIV reverse-transcriptase inhibitors

Iron-Catalyzed Oxidative Decarbonylative α-Alkylation of Acyl-Substituted Furans with Aliphatic Aldehydes as the Alkylating Agents

A protocol for FeCl₂-catalyzed oxidative decarbonylative α-alkylation of acyl furans using alkyl aldehydes as the alkylating agents has been developed. This protocol affords α-alkyl-α-acylfurans in moderate to good yields in a practical and sustainable fashion. Mechanistic studies suggest that the reaction proceeds via generation of an alkyl radical from the alkyl aldehyde, addition of the radical to the furan ring, and subsequent rearomatization.

(Ar-tpy)RuII(ACN)3: A Water-Soluble Catalyst for Aldehyde Amidation, Olefin Oxo-Scissoring, and Alkyne Oxygenation

The synthetic chemists always look for developing new catalysts, sustainable catalysis, and their applications in various organic transformations. Herein, we report a new class of water-soluble complexes, (Ar-tpy)Ru^II(ACN)₃, utilizing designed terpyridines possessing electron-donating and -withdrawing aromatic residues for tuning the catalytic activity of the Ru(II) complex. These complexes displayed excellent catalytic activity for several oxidative organic transformations including late-stage C-H functionalization of aldehydes with NH₂OR to valuable primary amides in nonconventional aqueous media with excellent yield. Its diverse catalytic power was established for direct oxo-scissoring of a wide range of alkenes to furnish aldehydes and/or ketones in high yield using a low catalyst loading in the water. Its smart catalytic activity under mild conditions was validated for dioxygenation of alkynes to highly demanding labile synthons, 1,2-diketones, and/or acids. This general and sustainable catalysis was successfully employed on sugar-based substrates to obtain the chiral amides, aldehydes, and labile 1,2-diketones. The catalyst is recovered and reused with a moderate turnover. The proposed mechanistic pathway is supported by isolation of the intermediates and their characterization. This multifaceted sustainable catalysis is a unique tool, especially for late-stage functionalization, to furnish the targeted compounds through frequently used amidation and oxygenation processes in the academia and industry.

Antileishmanial bis-arylimidamides: DB766 analogs modified in the linker region and bis-arylimidamide structure-activity relationships

Analogs of the lead antileishmanial bis-arylimidamide DB766 were prepared that possess unsymmetrical substitutions on the diphenylfuran linker, and an additional compound was synthesized that contains isopropoxy groups meta to the central furan. These agents all displayed nanomolar in vitro potency against intracellular Leishmania with selectivity indexes >100 compared to J774 macrophages. While the unsymmetrical analogs were toxic to mice when given ip at 30 mg/kg/day, the compound bearing the meta isopropoxy groups was well tolerated by mice and showed activity in a murine model of visceral leishmaniasis when administered ip at 30 mg/kg/day for five days.

Synthesis and antiviral activity of new dimeric inhibitors against HIV-1

This paper describes the synthesis and the antiviral activities of dimeric compounds derived from homo and asymmetric combinations of N-1 propynyloxymethyl analogues 1a,b of MKC-442, an N-1 4-iodobenzyloxymethyl analogue of TNK-651 5, potent contraceptive norgestrel and AZT. They were obtained by Sonogashira reaction, 'click' chemistry or Pd-catalyzed oxidative coupling. The iodo precursor 5 turned out as a potent compound against wild type and mutated HIV-1 virus. All dimeric compounds showed lower activity against HIV-1 than MKC-442, except the asymmetric dimer of AZT and 1a which showed an activity comparable to MKC-442.