Asian Journal of Organic Chemistry最新文献

The combination of HBr, TMSO (tetramethylene sulfoxide) and HFIP (hexafluoroisopropanol) has been utilized in the modification of pyrrolo[2,1-a]isoquinoline derivatives through bromination, dimerization and sulfenylation respectively. In these processes, HBr serves as the source of bromine and TMSO acts as an oxidant. HFIP also plays an essential role for the oxidative dimerization. Chemoselectivity can be easily controlled by adjusting the parameters such as reaction time, ratio of reagents and the addition of nucleophile.

Abietane type diterpenic (dehydroabietic, 2,3-dihydroquinopimaric and maleopimaric) acids were converted by the acid chloride method into a series of aliphatic and heterocyclic amine spacered conjugates. A number of structurally novel derivatives holding 1,2,3-triazole moieties were designed and synthesized by treating of the propargylated amides and esters with a sugar azides using the Cu(I)-catalyzed click chemistry approach. The synthesized N-containing diterpene derivatives were tested for their potential inhibition of influenza A/PuertoRico/8/34 (H1N1) virus in MDCK cell culture and SARS-CoV-2 pseudovirus in BHK-21-hACE2 cells. Among tested forty-five compounds ten derivatives were the most efficacious against influenza virus A with IC₅₀ 0.7–63.4 μM together with high selectivity index SI value from 11 from 94. Dihydroquinopimaric acid N-ethylpiperazine-amide and dehydroabietic acid 1,2,3-triazoles spacered with glucose and lactose showed anti-SARS-CoV-2 pseudovirus activity with EC₅₀ values of 1.79–25.46 μM. Molecular docking and dynamics modeling investigated the binding mode of the lead compounds into the binding pocket of influenza A virus M2 protein and the RBD domain of SARS-CoV-2 spike glycoprotein.

Considering the drawbacks associated with available synthetic methodologies of isoflavones, herein we have reported a metal-free and eco-friendly approach to these natural products. In the present study, we have carried out the synthesis of eight isoflavone derivatives 7a–7h using α-aryl-β,β-ditosyloxy ketone protocol. Initially, we have protected the 2’-hydroxy group of respective chalcone moiety in order to remove its interference under reaction conditions. The protected chalcones were then subjected to 1,2-aryl migration by being treated with hydroxy(tosyloxy)iodobenzene (HTIB) reagent in a non-nucleophilic solvent (CH₂Cl₂). This migration furnished the formation of α-aryl-β,β-ditosyloxy ketones via C−C bond formation from their corresponding chalcones in moderate to good yields (55–82 %). The ambiguity regarding the exact molecular structure of the α-aryl-β,β-ditosyloxy ketones was examined through the single crystal X-ray diffraction data. At last, the synthesis of isoflavones was carried out in moderate to good yields (50–80 %) by performing the reaction of α-aryl-β,β-ditosyloxy ketones with sodium hydroxide in aqueous methanol.

A synthetic protocol for the preparation of novel 3,4-pyrrolidine-fused β-lactams was developed. The proposed 2,6-diazabicyclo[3.2.0]heptan-7-one scaffolds were constructed through an amido group-induced, potassium tert-butoxide-promoted intramolecular ring closure of 3-acylamino-4-oxiranyl-β-lactams as the key reaction step. Alternatively, the desired cyclization was also effected by means of a scandium triflate-mediated catalytic approach. In this way, a set of stereodefined 3,4-pyrrolidine-fused β-lactams was synthesized, which were preliminary evaluated as β-lactamase inhibitors. These first-line biological assessments led to the identification of a 2-benzoyl-6-(4-methoxyphenyl)-substituted diazabicyclo structure as an eligible starting point for further β-lactamase inhibitor optimization studies.

The poor nucleofugality of the amino group renders the C−N bond functionalization of primary aromatic amines highly challenging. Herein, we report a direct substitution reaction of 2-aminotropones, bearing a unique non-benzenoid seven-membered aromatic ring that exists in some natural products and bioactive molecules, with potassium allyltrifluoroborates through C−N bond cleavage under transition-metal-free conditions. The amino group of 2-aminotropones were directly substituted with potassium allyltrifluoroborates in the presence of sodium bicarbonate, delivering structurally diverse 2-allyltropones in moderate to good yields. The reaction is free of directing groups, activating groups and transition metals, providing a convenient method to access substituted tropones.

Primary amides play a crucial role in organic and pharmaceutical synthesis. Herein, we present a rapid and convenient method for transforming diverse DNA-conjugated nitriles into primary amides utilizing hydrogen peroxide and potassium carbonate. The substrate scope and DEL compatibility of this reaction were thoroughly investigated, revealing a wide range of substrates with moderate-to-excellent conversion. This on-DNA transformation holds significant promise for constructing DNA-encoded libraries (DELs) and enabling late-stage functionalization to expand chemical diversity. Our approach not only highlights the versatility of the method but also underscores its potential for broad applications in organic and pharmaceutical synthesis.