DNA minor groove-binding ligands: a different class of mammalian DNA topoisomerase I inhibitors

DNA specific fluorescent symmetric dimeric bisbenzimidazoles DBP(n): the synthesis, spectral properties, and biological activity

A series of new fluorescent symmetric dimeric bisbenzimidazoles DBP(n) bearing bisbenzimidazole fragments joined by oligomethylene linkers with a central 1,4-piperazine residue were synthesized. The complex formation of DBP(n) in the DNA minor groove was demonstrated. The DBP(n) at micromolar concentrations inhibit in vitro eukaryotic DNA topoisomerase I and prokaryotic DNA methyltransferase (MTase) M.SssI. The DBP(n) were soluble well in aqueous solutions and could penetrate cell and nuclear membranes and stain DNA in live cells. The DBP(n) displayed a moderate effect on the reactivation of gene expression.

Probing the interaction of distamycin A with S100β: the "unexpected" ability of S100β to bind to DNA-binding ligands

DNA-minor-groove-binding ligands are potent antineoplastic molecules. The antibiotic distamycin A is the prototype of one class of these DNA-interfering molecules that have been largely used in vitro. The affinity of distamycin A for DNA is well known, and the structural details of the complexes with some B-DNA and G-quadruplex-forming DNA sequences have been already elucidated. Here, we show that distamycin A binds S100β, a protein involved in the regulation of several cellular processes. The reported affinity of distamycin A for the calcium(II)-loaded S100β reinforces the idea that some biological activities of the DNA-minor-groove-binding ligands arise from the binding to cellular proteins.

Minor grove binding ligands disrupt PARP-1 activation pathways

PARP-1 is a nuclear enzyme regulating transcription, chromatin restructuring, and DNA repair. PARP-1 is activated by interaction with NAD+, DNA, and core histones. Each route of PARP-1 activation leads to somewhat different outcomes. PARP-1 interactions with core histones control PARP-1 functions during transcriptional activation in euchromatin. DNA-dependent regulation of PARP-1 determines its localization in heterochromatin and PARP-1-dependent silencing. Here we address the biological significance of DNA-dependent PARP-1 regulation in vitro and in vivo. We report that minor grove binding ligands (MGBLs) specifically target PARP-1 interaction with DNA, and, hence, the DNA-dependent pathway of PARP-1 activation. By obstructing its interaction with DNA molecules, MGBLs block PARP-1 activity in vitro and in vivo, as we demonstrate using Drosophila, as well as human cancer-derived cells. We also demonstrate synergistic inhibition of PARP-1, combining MGBLs with conventional NAD+-dependent inhibitors in human cancer cells. These results suggest that combining different classes of PARP-1 inhibitors can precisely modulate PARP-1 activity in living cells, thus holding promise for new avenues of cancer treatment.

DAST-promoted Beckmann rearrangement/intramolecular cyclization of acyclic ketoximes: access to 2-oxazolines, benzimidazoles and benzoxazoles

The first example of DAST-promoted Beckmann rearrangement/intramolecular cyclization of acyclic ketoximes is described, which affords 2-oxazolines, benzimidazoles and benzoxazoles.

Synthesis, DNA interaction and anticancer activity of 2-anthryl substituted benzimidazole derivatives

2-Anthryl substituted benzimidazole derivatives were synthesized and anticancer activity, cellular uptake, DNA interaction and molecular docking studies have been accomplished.

Nitric oxide inhibition, antioxidant, and antitumour activities of novel copper(ii) bis-benzimidazole diamide nanocoordination complexes

Antitumor effect illustrated by changes in body weight. In control mice, body weight increased to 11.5 g but when treated withC3, body weight difference as compared to the control decreased by 4.7 g and decreased to 2.2 g and 0.6 g withC1andC2, respectively.

A monofunctional platinum(II)-based anticancer agent from a salicylanilide derivative: Synthesis, antiproliferative activity, and transcription inhibition

Cationic monofunctional platinum(II)-based anticancer agents with a general formula of cis-[Pt(NH3)2(N-donor)Cl](+) have recently drawn significant attention due to their unique mode of action, distinctive anticancer spectrum, and promising antitumor activity both in vitro and in vivo. Understanding the mechanism of action of novel monofunctional platinum compounds through rational drug design will aid in the further development of active agents. In this study, we synthesized and evaluated a monofunctional platinum-based anticancer agent SA-Pt containing a bulky salicylanilide moiety. The antiproliferative activity of SA-Pt was close to that of cisplatin. Mechanism studies revealed that SA-Pt entered HeLa cells more efficiently than cisplatin, blocked the cell cycle at the S-phase, and induced apoptosis. The compound bound to DNA as effectively as cisplatin, but did not block RNA polymerase II-mediated transcription as strongly as cisplatin, indicating that once the compound formed Pt-DNA lesions, the salicylanilide group was more easily recognized and removed. This study not only enriches the family of monofunctional platinum-based anticancer agents but also guides the design of more potent monofunctional platinum complexes.

Correlative organelle fluorescence microscopy and synchrotron X-ray chemical element imaging in single cells

X-ray chemical element imaging has the potential to enable fundamental breakthroughs in the understanding of biological systems because chemical element interactions with organelles can be studied at the sub-cellular level. What is the distribution of trace metals in cells? Do some elements accumulate within sub-cellular organelles? What are the chemical species of the elements in these organelles? These are some of the fundamental questions that can be addressed by use of X-ray chemical element imaging with synchrotron radiation beams. For precise location of the distribution of the elements, identification of cellular organelles is required; this can be achieved, after appropriate labelling, by use of fluorescence microscopy. As will be discussed, this approach imposes some limitations on sample preparation. For example, standard immunolabelling procedures strongly modify the distribution of the elements in cells as a result of the chemical fixation and permeabilization steps. Organelle location can, however, be performed, by use of a variety of specific fluorescent dyes or fluorescent proteins, on living cells before cryogenic fixation, enabling preservation of element distribution. This article reviews the methods used for fluorescent organelle labelling and X-ray chemical element imaging and speciation of single cells. Selected cases from our work and from other research groups are presented to illustrate the potential of the combination of the two techniques.

Calcein-effluxing human colon cancer cells are enriched for self-renewal capacity and depend on β-catenin

Putative cancer stem cells are a subpopulation of cancer cells that give rise to chemotherapy resistance and are therefore of prognostic and therapeutic interest, though their identification remains elusive in colon cancer due to lack of reliable and accurate markers. We previously identified a p53-dependent putative cancer stem cell population, the calcein low population (C(lo)P), based on their exclusive efflux of the fluorescent dye Calcein. This functional identification method enables comparative live cell studies of subpopulations without differential toxicity that occurs with traditional Hoechst methods, which has confounded conclusions and limited the utility of this cancer stem cell marker. In this study, we examined the cancer stem cell-like properties of the C(lo)P population in vivo in comparison with the parental and calcein-high population (C(hi)P) in human colon cancer xenografts. Serial dilution xenograft experiments in NOD/SCID mice revealed that the C(lo)P is only marginally more tumorigenic compared to the C(hi)P or parental cells. However, serial passage of these tumors revealed that the C(lo)P is uniquely enriched for self-renewal capacity in vivo compared to the other populations. Immunohistochemical analysis of these tumors revealed that the C(lo)P possesses increased levels of nuclear β-catenin and furthermore, siRNA-mediated knockdown of β-catenin significantly reduced the C(lo)P population. These findings highlight the C(lo)P as an important subpopulation of tumor cells that are exclusively endowed with the ability to self-renew and propagate tumors. The dependency of the C(lo)P on β-catenin provides a molecular explanation for this ability and suggests that this population can and should be therapeutically targeted by inhibition of Wnt signaling.

Selective Inhibition of Bacterial Topoisomerase I by alkynyl-bisbenzimidazoles

Hoechst dyes are well known DNA binders that non-selectively inhibit the function of mammalian topoisomerase I and II. Herein, we show that Hoechst 33258 based bisbenzimidazoles (DPA 151-154), containing a terminal alkyne, are effective and selective inhibitors of E. coli. topoisomerase I. These bisbenzimidazoles displayed topoisomerase I inhibition much better than Hoechst 33342 or Hoechst 33258 with IC50 values in the range of 2.47-6.63 μM. Bisbenzimidazoles DPA 151-154 also display selective inhibition of E. coli. topoisomerase I over DNA gyrase and Human topoisomerases I and II, and effectively inhibit bacterial growth.

Flow cytometry of the side population (SP)

The side population (SP) has become an important hallmark for the definition of the stem-cell compartment, especially for the detection of stem cells and for their physical isolation by fluorescence-activated cell sorting (FACS). SP cells are CD34(-) and were discovered using ultraviolet excitation based on the efflux of Hoechst 33342 (Ho342). Although the method works as originally described, the protocol is difficult for most investigators to perform: first, because the ability to discriminate SP cells is based on the differential retention of Ho342 during a functional assay; second, because of the difficulties in setting the right experimental and acquisition conditions; and third, because analysis of the acquired data requires extensive expertise in flow cytometry to accurately detect the SP events. More recently, a new assay based on the efflux of Vybrant DyeCycle Violet stain (DCV) has been documented to discriminate SP cells. This unit contains many helpful pointers to aid the user in obtaining the best possible results with these assays.

R. T, Soung NK, Jang JH, Kim YS, Lee KS, Kwon YT, Asami Y, Ahn JS, Erikson RL, Kim BY. STK295900, a dual inhibitor of topoisomerase 1 and 2, induces G(2) arrest in the absence of DNA damage

STK295900, a small synthetic molecule belonging to a class of symmetric bibenzimidazoles, exhibits antiproliferative activity against various human cancer cell lines from different origins. Examining the effect of STK295900 in HeLa cells indicates that it induces G(2) phase arrest without invoking DNA damage. Further analysis shows that STK295900 inhibits DNA relaxation that is mediated by topoisomerase 1 (Top 1) and topoisomerase 2 (Top 2) in vitro. In addition, STK295900 also exhibits protective effect against DNA damage induced by camptothecin. However, STK295900 does not affect etoposide-induced DNA damage. Moreover, STK295900 preferentially exerts cytotoxic effect on cancer cell lines while camptothecin, etoposide, and Hoechst 33342 affected both cancer and normal cells. Therefore, STK295900 has a potential to be developed as an anticancer chemotherapeutic agent.

Zirconyl (IV) Nitrate as Efficient and Reusable Solid Lewis Acid Catalyst for the Synthesis of Benzimidazole Derivatives

The present paper introduces a simple and efficient method for the synthesis of substituted benzimidazoles by heterocyclization of differento-phenylenediamines and substituted aromatic carboxylic acid/aldehyde in the presence of zirconyl nitrate as catalyst in ethanol under reflux, which produced excellent yield of corresponding benzimidazoles in a short reaction time with reusability of catalyst.

The anticancer multi-kinase inhibitor dovitinib also targets topoisomerase I and topoisomerase II

Dovitinib (TKI258/CHIR258) is a multi-kinase inhibitor in phase III development for the treatment of several cancers. Dovitinib is a benzimidazole-quinolinone compound that structurally resembles the bisbenzimidazole minor groove binding dye Hoechst 33258. Dovitinib bound to DNA as shown by its ability to increase the DNA melting temperature and by increases in its fluorescence spectrum that occurred upon the addition of DNA. Molecular modeling studies of the docking of dovitinib into an X-ray structure of a Hoechst 33258-DNA complex showed that dovitinib could reasonably be accommodated in the DNA minor groove. Because DNA binders are often topoisomerase I (EC 5.99.1.2) and topoisomerase II (EC 5.99.1.3) inhibitors, the ability of dovitinib to inhibit these DNA processing enzymes was also investigated. Dovitinib inhibited the catalytic decatenation activity of topoisomerase IIα. It also inhibited the DNA-independent ATPase activity of yeast topoisomerase II which suggested that it interacted with the ATP binding site. Using isolated human topoisomerase IIα, dovitinib stabilized the enzyme-cleavage complex and acted as a topoisomerase IIα poison. Dovitinib was also found to be a cellular topoisomerase II poison in human leukemia K562 cells and induced double-strand DNA breaks in K562 cells as evidenced by increased phosphorylation of H2AX. Finally, dovitinib inhibited the topoisomerase I-catalyzed relaxation of plasmid DNA and acted as a cellular topoisomerase I poison. In conclusion, the cell growth inhibitory activity and the anticancer activity of dovitinib may result not only from its ability to inhibit multiple kinases, but also, in part, from its ability to target topoisomerase I and topoisomerase II.

The therapeutic journey of benzimidazoles: a review

Presence of benzimidazole nucleus in numerous categories of therapeutic agents such as antimicrobials, antivirals, antiparasites, anticancer, anti-inflammatory, antioxidants, proton pump inhibitors, antihypertensives, anticoagulants, immunomodulators, hormone modulators, CNS stimulants as well as depressants, lipid level modulators, antidiabetics, etc. has made it an indispensable anchor for development of new therapeutic agents. Varied substitutents around the benzimidazole nucleus have provided a wide spectrum of biological activities. Importance of this nucleus in some activities like, Angiotensin I (AT(1)) receptor antagonism and proton-pump inhibition is reviewed separately in literature. Even some very short reviews on biological importance of this nucleus are also known in literature. However, owing to fast development of new drugs possessing benzimidazole nucleus many research reports are generated in short span of time. So, there is a need to couple the latest information with the earlier information to understand the current status of benzimidazole nucleus in medicinal chemistry research. In the present review, various derivatives of benzimidazole with different pharmacological activities are described on the basis of substitution pattern around the nucleus with an aim to help medicinal chemists for developing an SAR on benzimidazole derived compounds for each activity. This discussion will further help in the development of novel benzimidazole compounds.

DNA topoisomerase I drugs and radiotherapy for lung cancer

Lung cancer represents the most common cause of cancer-related mortality in the United States and around the world. DNA topoisomerase I (TOP1) drugs such as irinotecan and topotecan represent a unique class of chemotherapeutic agents that exhibit not only potent cytotoxic effect, but also tumor-selective radiation-sensitizing effect. The mechanism of cytotoxicity and radiation sensitization by TOP1 drugs has been intensely investigated. Modern radiotherapy, aided by improved imaging and treatment delivery technology, is capable of targeting tumors more precisely, while sparing surrounding critical structures. Clinical trials with camptothecin derivatives and radiotherapy have been conducted in lung cancers. Combined modality therapy with TOP1 drugs and radiotherapy offers a new frontier for lung cancer therapy. We review the present state of TOP1-targeted chemotherapy and modern radiotherapy for lung cancer.

Antioxidation and DNA-binding properties of binuclear lanthanide(III) complexes with a Schiff base ligand derived from 8-hydroxyquinoline-7-carboxaldehyde and benzoylhydrazine

8-Hydroxyquinoline-7-carboxaldehyde (8-HQ-7-CA), Schiff-base ligand 8-hydroxyquinoline-7-carboxaldehyde benzoylhydrazone, and binuclear complexes [LnL(NO(3))(H(2)O)(2)](2) were prepared from the ligand and equivalent molar amounts of Ln(NO(3))·6H(2)O (Ln=La(3+), Nd(3+), Sm(3+), Eu(3+), Gd(3+), Dy(3+), Ho(3+), Er(3+), Yb(3+), resp.). Ligand acts as dibasic tetradentates, binding to Ln(III) through the phenolate O-atom, N-atom of quinolinato unit, and C=N and -O-C=N- groups of the benzoylhydrazine side chain. Dimerization of this monomeric unit occurs through the phenolate O-atoms leading to a central four-membered (LnO)(2) ring. Ligand and all of the Ln(III) complexes can strongly bind to CT-DNA through intercalation with the binding constants at 10(5)-10(6) M(-1). Moreover, ligand and all of the Ln(III) complexes have strong abilities of scavenging effects for hydroxyl (HO·) radicals. Both the antioxidation and DNA-binding properties of Ln(III) complexes are much better than that of ligand.

A novel multiplex cell viability assay for high-throughput RNAi screening

Cell-based high-throughput RNAi screening has become a powerful research tool in addressing a variety of biological questions. In RNAi screening, one of the most commonly applied assay system is measuring the fitness of cells that is usually quantified using fluorescence, luminescence and absorption-based readouts. These methods, typically implemented and scaled to large-scale screening format, however often only yield limited information on the cell fitness phenotype due to evaluation of a single and indirect physiological indicator. To address this problem, we have established a cell fitness multiplexing assay which combines a biochemical approach and two fluorescence-based assaying methods. We applied this assay in a large-scale RNAi screening experiment with siRNA pools targeting the human kinome in different modified HEK293 cell lines. Subsequent analysis of ranked fitness phenotypes assessed by the different assaying methods revealed average phenotype intersections of 50.7±2.3%–58.7±14.4% when two indicators were combined and 40–48% when a third indicator was taken into account. From these observations we conclude that combination of multiple fitness measures may decrease false-positive rates and increases confidence for hit selection. Our robust experimental and analytical method improves the classical approach in terms of time, data comprehensiveness and cost.

New insight into the molecular mechanisms of the biological effects of DNA minor groove binders

BACKGROUND

Bisbenzimides, or Hoechst 33258 (H258), and its derivative Hoechst 33342 (H342) are archetypal molecules for designing minor groove binders, and widely used as tools for staining DNA and analyzing side population cells. They are supravital DNA minor groove binders with AT selectivity. H342 and H258 share similar biological effects based on the similarity of their chemical structures, but also have their unique biological effects. For example, H342, but not H258, is a potent apoptotic inducer and both H342 and H258 can induce transgene overexpression in in vitro studies. However, the molecular mechanisms by which Hoechst dyes induce apoptosis and enhance transgene overexpression are unclear.

METHODOLOGY/PRINCIPAL FINDINGS

To determine the molecular mechanisms underlying different biological effects between H342 and H258, microarray technique coupled with bioinformatics analyses and multiple other techniques has been utilized to detect differential global gene expression profiles, Hoechst dye-specific gene expression signatures, and changes in cell morphology and levels of apoptosis-associated proteins in malignant mesothelioma cells. H342-induced apoptosis occurs in a dose-dependent fashion and is associated with morphological changes, caspase-3 activation, cytochrome c mitochondrial translocation, and cleavage of apoptosis-associated proteins. The antagonistic effect of H258 on H342-induced apoptosis indicates a pharmacokinetic basis for the two dyes' different biological effects. Differential global gene expression profiles induced by H258 and H342 are accompanied by unique gene expression signatures determined by DNA microarray and bioinformatics software, indicating a genetic basis for their different biological effects.

CONCLUSIONS/SIGNIFICANCE

A unique gene expression signature associated with H342-induced apoptosis provides a new avenue to predict and classify the therapeutic class of minor groove binders in the drug development process. Further analysis of H258-upregulated genes of transcription regulation may identify the genes that enhance transgene overexpression in gene therapy and promote recombinant protein products in biopharmaceutical companies.

DATA DEPOSITION

The microarray data reported in this article have been deposited in the Gene Expression Omnibus (GEO) database, www.ncbi.nlm.nih.gov/geo (accession no.GSE28616).

A photoinduced pH jump applied to drug release from cucurbit[7]uril

A proof-of-principle for the application of a photoinduced pH jump for delivery of the Hoechst 33258 drug by disassembly of its host-guest complex with cucurbit[7]uril is described.

Hoechst 33342 induces radiosensitization in malignant glioma cells via increase in mitochondrial reactive oxygen species

Mitochondrial DNA plays an important role in cellular sensitivity to cancer therapeutic agents. Hoechst 33342, a DNA minor groove binding ligand, has shown radiosensitizing effects in different cancer cell lines. In the present study, the possible binding of Hoechst 33342 with mitochondrial DNA, isolated from human cerebral glioma (BMG-1) cells, was investigated and consequences of this binding on excessive reactive oxygen species (ROS) generation in irradiated BMG-1 cells were studied. Alteration in the fluorescence spectroscopic characteristics of Hoechst 33342 suggested binding of Hoechst 33342 with isolated mitochondria and mitochondrial DNA. Persistent increase in level of ROS in the presence of Hoechst 33342 has been observed, which was further enhanced in irradiated cells. Investigations using inhibitors of ETC complex I suggested that mitochondrial bound Hoechst 33342 contributed to increased ROS, which was associated with alteration in DeltaPsim and antioxidant machinery. These factors appeared to contribute in potentiating radiation-induced cell death in BMG-1 cells. The finding from these studies will be useful in designing better anti-cancer strategies.

Efficient assembly of 1-(1H-imidazol-1-yl)-3-methylene-1H-indenes via tandem reaction of (2-(alkynyl)benzylidene)malonates with imidazoles

The tandem nucleophilic addition and 5-exo-cyclization of (2-(alkynyl)benzylidene)malonates with imidazole derivatives in the presence of t-BuOK is reported. This reaction proceeds smoothly under mild conditions with high selectivity to afford the corresponding 1-(1H-imidazol-1-yl)-3-methylene-1H-indene-2,2(3H)-dicarboxylates in good to excellent yields.

Fluorescent and ultraviolet-visible spectroscopy studies on the antioxidation and DNA binding properties of binuclear Tb(III) complexes

Tb(III) complexes were prepared from Tb(NO(3))(3)·6H(2)O and four Schiff-base ligands derived from 8-hydroxyquinoline-2-carboxaldehyde with aroylhydrazines. X-ray crystal and other structural analyses indicate that Tb(III) and every ligand can form a binuclear Tb(III) complex with 1:1 metal-to-ligand stoichiometry and nine-coordination at the Tb(III) center. Viscosity titration experiments and fluorescent and ultraviolet-visible (UV-Vis) spectroscopy results indicate that all the Tb(III) complexes can bind to Calf thymus DNA through intercalation with the binding constants at the order of magnitude of 10(6)-10(7) M(-1), and they may be used as potential anticancer drugs, but complexes containing active phenolic hydroxy groups may have stronger antitumor activities. Antioxidation results indicate that all the Tb(III) complexes have strong abilities of scavenging hydroxyl radicals and superoxide radicals, but complexes containing active phenolic hydroxy groups show stronger scavenging effects on hydroxyl radicals and complexes containing N-heteroaromatic substituent show stronger scavenging effects on superoxide radicals. However, Tb(III) emission with these systems is not observed, for these ligands rather are quenchers and unable to sensitize this metal ion.

Triple recognition of B-DNA by a neomycin-Hoechst 33258-pyrene conjugate

Recent developments have indicated that aminoglycoside binding is not limited to RNA, but to nucleic acids that, like RNA, adopt conformations similar to its A-form. We further sought to expand the utility of aminoglycoside binding to B-DNA structures by conjugating neomycin, an aminoglycoside antibiotic, with the B-DNA minor groove binding ligand Hoechst 33258. Envisioning a dual groove binding mode, we have extended the potential recognition process to include a third, intercalative moiety. Similar conjugates, which vary in the number of binding moieties but maintain identical linkages to allow direct comparisons to be made, have also been prepared. We report herein novel neomycin- and Hoechst 33258-based conjugates developed in our laboratories for exploring the recognition potential with B-DNA. Spectroscopic studies such as UV melting, differential scanning calorimetry, isothermal fluorescence titrations, and circular dichroism together illustrate the triple recognition of the novel conjugate containing neomycin, Hoechst 33258, and pyrene. This study represents the first example of DNA molecular recognition capable of minor versus major groove recognition in conjunction with intercalation.

Antioxidation and DNA-binding properties of binuclear Er(III) complexes with Schiff-base ligands derived from 8-hydroxyquinoline-2-carboxaldehyde and four aroylhydrazines

The Er(III) complexes are prepared from Er(NO(3))(3).6H(2)O and Schiff-base ligands derived from 8-hydroxyquinoline-2-carboxaldehyde with four aroylhydrazines, including benzoylhydrazine, 2-hydroxybenzoylhydrazine, 4-hydroxybenzoylhydrazine and isonicotinylhydrazine, respectively. X-ray crystal and other structural analyses indicate that Er(III) and every ligand can form a binuclear Er(III) complex with nine-coordination and 1: 1 metal-to-ligand stoichiometry at the Er(III) centre. All the Er(III) complexes can bind to calf thymus DNA through intercalation with the binding constants at the order of magnitude 10(6) M(-1), and they may be used as potential anticancer drugs. All the Er(III) complexes have strong scavenging effects for hydroxyl radicals and superoxide radicals; however, complex containing active phenolic hydroxyl group shows stronger scavenging effects for hydroxyl radicals and complex containing N-heteroaromatic substituent shows stronger scavenging effects for superoxide radicals.

An Efficient Stereo Selective Synthesis of Benzyl, (Benzimidazol-2-yl)-Methyl and (6H-Imidazo[4,5-e][2,1,3]Benzothiadiazol-7-yl)Methyl Styryl Sulfones

A facile and an efficient one-pot synthesis of (E)-styryl sulfones is described by condensation of 2-(chloromethyl)benz-imidazoles or 7-(chloromethyl)-6H-imidazo[4,5-e][2,1,3]benzothiadiazole or benzyl bromides with sodium (E)-styryl sulfinates in DMF gave corresponding styryl sulfones. They have been prepared in good yields, in the absence of any catalyst.