Temperature-Controlled Desulfonylative Condensation of α-Sulfonyl o-Hydroxyacetophenones and 2-Formyl Azaarenes: Synthesis of Azaaryl Aurones and Flavones

K2CO3/TFAA-activated diarylation of α-sulfonyl o-hydroxyacetophenones with o-nitroaryl disulfides to construct sulfonyl bis-o-nitroaryl acetophenones

A concise K2CO3/TFAA-mediated diarylation of readily accessible sulfonyl o-hydroxyacetophenones with o-nitroaryl disulfides is described. This single-step strategy provides a variety of functionalized sulfonyl C- and O-bis-o-nitroaryl acetophenones via the formation of one carbon-carbon single bond and one carbon-oxygen single bond. A plausible mechanism is proposed and discussed. The molecular structures of key products were determined by X-ray analysis.

Synthesis of 4-sulfonyl-1,7-diesters via K2CO3-mediated alkylative debenzoylation of α-sulfonyl o-hydroxyacetophenones with acrylates

The synthesis of 4-sulfonyl-1,7-diesters was well developed, under open-vessel conditions, by K2CO3-mediated double alkylation of α-sulfonyl o-hydroxyacetophenones with acrylates and tandem debenzoylation of the resulting α,α-disubstituted o-hydroxyacetophenones. A plausible mechanism is proposed and discussed here. This high-yielding protocol provides a highly effective intermolecular alkylation and intramolecular debenzoylation via the formation of two carbon-carbon (C-C) single bonds and the cleavage of a carbon-carbon (C-C) single bond.

Synthesis of sulfonyl 2-aryl-5-methylenyltetrahydropyrans

In this study, the present research describes a high-yield method for the synthesis of sulfonyl 2-aryl-5-methylenetetrahydropyrans by one-pot straightforward DABCO-promoted intramolecular Michael addition of β-sulfonyl styrene with 2-chloromethyl-1-propenol followed by intramolecular alkylation. This Baylis-Hillman-type pathway provides a highly effective stereoselective annulation by forming one carbon-oxygen bond and one carbon-carbon bond.

Design, synthesis and anticancer evaluation of polymethoxy aurones as potential cell cycle inhibitors

Background

Cancer is the most fatal disease in humans and the aberrant activity of various cell cycle proteins results in uncontrolled tumor cell proliferation, thus, regulating the cell cycle is an attractive target in cancer therapy.

Objectives

Aurone is a naturally occurring active compound with a wide range of biological activities, of which 3, 4, 5-trimethoxyphenyl (TMP) is an important microtubule targeting pharmacophore. Based on the pharmacophore combination principle, we incorporate the TMP pharmacophore into the aurone structure and design a novel polymethoxy derivative that is expected to inhibit tumor cell proliferation through regulating the cell cycle.

Methods

By introducing different substituents on C-4' and C-3', a series of new 4, 5, 6-trimethoxy aurone derivatives have been designed and synthesized. DU145, MCF-7 and H1299 cell lines were selected to evaluate their anticancer activity. The compound with the best cytotoxicity was then selected and the anticancer mechanisms were investigated by network pharmacology, flow cytometry, Western blot, and cell heat transfer assay. ADMET prediction evaluated the draggability of aurone derivatives.

Results

Aurones 1b and 1c have selective anti-proliferative activity against DU145 cells. Among them, the compound 1c have better cytotoxicity against DU145. Compound 1c could bind the active cavity of CyclinB1/CDK1/CKS complex protein and induced G2/M phase arrest of DU145 cells by regulating the expression of CyclinB1 and p21. Compound 1c satisfies the Lipinski rule, is suitable for the absorption and metabolism index, and has a lower risk of cardiac toxicity.

Conclusions

Polymethoxy aurones 1c might function as a CyclinB1/CDK1 inhibitor that deserved to be further developed for the treatment of prostate cancer.

Synthesis, Nematicidal Evaluation, and the Structure-Activity Relationship Study of Aurone Derivatives

Plant-parasitic nematodes (PPNs) are one of the major threats to modern agriculture. Chemical nematicides are still required for the management of PPNs. Based on our previous work, the structure of aurone analogues was obtained using a hybrid 3D similarity calculation method (SHAFTS, SHApe-FeaTure Similarity). Thirty-seven compounds were synthesized. The nematicidal activity of target compounds against Meloidogyne incognita (root-knot nematode, M. incognita) was evaluated, and the structure-activity relationship of synthesized compounds was analyzed. The results showed that compound 6 and some of its derivatives exhibited impressive nematicidal activity. Among these compounds, compound 32 bearing 6-F showed the best in vitro and in vivo nematicidal activity. Its lethal concentration 50% after exposure to 72 h (LC_50/72 h) value was 1.75 mg/L, and the inhibition rate reached 97.93% in the sand at 40 mg/L. At the same time, compound 32 also exhibited excellent inhibition on egg hatching and moderate inhibition on the motility of Caenorhabditis elegans (C. elegans).

Tandem C- and O-alkylative annulation of β-ketosulfones with 1,2-bisbromomethyl arenes: one-pot construction of sulfonyl indanes and dioxadibenzofused macrocycles

Herein, a tandem synthetic route for constructing sulfonyl indanes and dioxadibenzofused macrocycles is described. This strategy involves a transition-metal-free, base-mediated tandem C- and O-alkylative annulation of β-ketosulfones with 1,2-bisbromomethyl arenes with moderate to excellent yields under open-vessel reaction conditions. In the overall reaction process, two carbon-carbon (C-C) and two carbon-oxygen (C-O) bonds are formed. Various base-promoted reaction conditions are screened for this one-pot easy-to-operate conversion.

Metal-free hydrosulfonylation of α,β-unsaturated ketones: synthesis and application of γ-keto sulfones

γ-Keto sulfones are versatile building blocks and valuable intermediates in organic synthesis and pharmaceutical chemistry. Motivated by their excellent properties, we herein report a green, convenient, metal-free hydrosulfonylation method for a variety of ynones, vinyl ketones, and sodium sulfinates in the absence of stoichiometric oxidants. This operationally simple protocol provides straightforward and practical access to a wide range of γ-keto sulfones with broad functional group tolerance from easily available starting materials. Moreover, the β,γ-unsaturated keto sulfones could further react with 2,3-butadienoate to generate cyclopentenes in phosphine-mediated [3 + 2] cycloaddition.

BF3·OEt2-mediated nucleophilic fluorocyclization of sulfonyl 3-methylene-oxabenzocyclooctan-6-ones. Diastereocontrolled synthesis of benzofused fluorooxabicyclo[4.2.1]nonanes

We describe a facile-operational, high-yield method for the diastereocontrolled preparation of novel sulfonyl benzofused fluorooxabicyclo[4.2.1]nonanes by a straightforward synthetic route, including (i) NaBH₄-mediated reduction of sulfonyl 3-methylene-oxabenzocyclooctan-6-ones and (ii) BF₃·OEt₂-mediated intramolecular nucleophilic fluorocyclization. The plausible mechanism for the preparation is proposed and discussed. This protocol can easily install a fluoro-atom on the bridged head position in a short time and under mild conditions, resulting in one carbon-carbon and one carbon-fluorine bond formation.

Tandem cyclocondensation of 1,3-bis-sulfonylpropan-2-ones with arylaldehydes. One-pot synthesis of tris-sulfonyl 3-arylphenols

One-pot tandem piperidinium acetate-mediated cyclocondensation of 1,3-bis-sulfonylpropan-2-ones with arylaldehydes generates tris-sulfonyl 3-arylphenols in moderate to good yields in refluxing toluene under easy-operational reaction conditions.

Synthesis of benzofused cyclobutaoxepanones via intramolecular annulation of o-cinnamyl chalcones

Intramolecular stereoselective annulation of o-cinnamyloxy chalcones provides two kinds of tricyclic benzofused cyclobutaoxepanones via the synthesized routes of DABCO/NBS (1,4-diazabicyclo[2.2.2]octane/N-bromosuccinimide)-mediated Baylis-Hillman type cyclization or low-pressure mercury (LP Hg) lamp-promoted photocontrolled [2 + 2] cycloaddition. Diversified reaction conditions have been investigated for one-pot facile, high-yield transformation.

Recent advances on synthesis and biological activities of aurones

Aurones are naturally occurring structural isomerides of flavones that have diverse bioactivities including antiviral, antibacterial, antifungal, anti-inflammatory, antitumor, antimalarial, antioxidant, neuropharmacological activities and so on. They constitute an important class of pharmacologically active scaffolds that exhibit multiple biological activities via diverse mechanisms. This review article provides an update on the recent advances (2013-2020.4) in the synthesis and biological activities of these derivatives. In the cases where sufficient information is available, some important structure-activity relationships (SAR) of their biological activities were presented, and on the strength of our expertise in medicinal chemistry and careful analysis of the recent literature, for the potential of aurones as medicinal drugs is proposed.

One-pot construction of dispirocyclohexanes via K2CO3-mediated desulfonylative Michael-Michael-aldol (2 + 2 + 2) annulation of sulfonyl 2-pyridyl flavanones and methylketones

K2CO3-mediated one-pot tandem conversion from sulfonyl 2-pyridyl flavanones to dipyridyl dispirocyclohexanes with contiguous multiple stereogenic centers was accomplished in good yields via an intramolecular desulfonylative ring-contraction of sulfonyl 2-pyridyl flavanones followed by an intermolecular Michael-Michael-aldol (2 + 2 + 2) annulation of the resulting pyridyl aurone intermediate with methyl ketones under facile, open-vessel, inexpensive and environmentally friendly reaction conditions. A plausible mechanism is proposed and discussed herein. This protocol provides a highly effective ring-closure via three carbon-carbon (C-C) bond formation.

p-TsOH-mediated synthesis of substituted 2,4-diaryl-3-sulfonylquinolines from functionalized 2-aminobenzophenones and aromatic β-ketosulfones under microwave irradiation

This study describes an efficient protocol for the preparation of substituted 2,4-diaryl-3-sulfonylquinolines from functionalized 2-aminobenzophenones and aromatic β-ketosulfones by using p-toluenesulfonic acid monohydrate under microwave irradiation. In this atom-economical synthetic route, a series of pharmaceutically active 3-arylsulfonylquinolines with good functional group tolerance are prepared in good to excellent yields. Some structures are confirmed by single-crystal X-ray diffraction analysis.

Gram-Scale Synthesis of 3-Sulfonyl Flavanones

In this paper, an easy-operational, high-yielding method for the gram-scale synthesis of 3-sulfonyl flavanones is described by a one-pot straightforward POCl₃ mediated intermolecular (5 + 1) annulation of the β-ketosulfones with an o-hydroxyaryl group (dual nucleophile) and arylaldehydes (dual electrophile) in refluxing toluene for 3 h. A plausible mechanism is proposed and discussed. This protocol provides a highly effective annulation via one carbon-oxygen (C-O) and one carbon-carbon (C-C) bond formations.

In(OTf)3-catalyzed intramolecular hydroarylation of α-phenylallyl β-ketosulfones – synthesis of sulfonyl 1-benzosuberones and 1-tetralones

In(OTf)₃-catalyzed intramolecular hydroarylation of α-phenylallyl β-ketosulfones provides sulfonyl 1-benzosuberones and 1-tetralones in moderate to good yields in refluxing (CH₂Cl)₂ under open-vessel and easy-operation reaction conditions. A plausible mechanism is proposed and discussed. This highly regioselective protocol provides an atom-economic ring-closure route.

In(OTf)₃-catalyzed intramolecular hydroarylation of α-phenylallyl β-ketosulfones provides sulfonyl 1-benzosuberones and 1-tetralones in moderate to good yields in refluxing (CH₂Cl)₂ under open-vessel and easy-operation reaction conditions.

Construction of Sulfonyl Dihydrobenzo[c]xanthen-7-ones Core via NH4OAc/PdCl2/CuCl2-Mediated Double Cyclocondensation of α-Sulfonyl o-Hydroxyacetophenones with 2-Allylbenzaldehydes

NH₄OAc/PdCl₂/CuCl₂ mediated domino double cyclocondensation of α-sulfonyl o-hydroxyacetophenones and 2-allylbenzaldehydes provides tetracyclic sulfonyl dihydrobenzo[c]xanthen-7-one core with good to excellent yields in MeOH. The intermediates contain a 3-sulfonyl flavanone motif. Only water is generated as a byproduct. The use of various catalysts and reaction conditions is studied for the facile-operational conversion.