4-substituted Phenyl Research Articles

Rigidification of Poly(p-phenylene)s through ortho-Phenyl Substitution.

A sterically π-congested ortho-phenylated poly(p-phenylene) (PPP) has been synthesized with unprecedentedly high molecular weights up to 29 kDa after fractionation, as confirmed by gel permeation chromatography coupled with a multiangle laser light scattering detector. The chain translation diffusion coefficient obtained from dynamic light scattering experiments displayed strong scaling (∼Lw–0.8) to the chain contour length, indicating a rodlike shape with remarkably high rigidity of this novel PPP. These results provide an interesting insight into the relationship between the structure and the chain stiffness of PPP-based polymers and challenge the validity of the existing diffusion models in polymer physics.

Comparative studies of photophysics and exciton dynamics of different diphenylanthracene (DPA) nanoaggregates

Diphenyl derivatives of anthracene (DPA) have attracted extensive research interest in recent time due to their prospective application in organic light emitting diode (OLED) and other optoelectronic devices. Systematic investigation on the influence of phenyl substitution on optical properties of anthracene is lacking, even though the positions of phenyl substitution in the anthracene moiety are expected to alter the molecular interaction and molecular packing in solid state, having impact on photophysics and excitonic properties of these materials. In present work, we have investigated photophysics of three DPA derivatives namely, 2,6-diphenylanthracene, 1,8-diphenylanthracene and 9,10-diphenylanthracene in their nanoaggregate form. Owing to different positions and different dihedral angles (relative to anthracene plane) of the phenyl substituents, crystalline packing and intermolecular interaction are significantly modulated, resulting in diverse photophysical properties in nanoaggregated state. We have discussed the role of phenyl substituents on the interplay of exciton - excimer photophysics and exciton diffusion properties of these anthracene derivatives in relation to their potential application in OLED and photovoltaic devices.

Synthesis, analgesic and anti-inflammatory activity of benzofuran pyrazole heterocycles

Abstract The present work describes the synthesis of series of 3-(5- Substituted -1-benzofuran-2-yl)-1-(4-substituted phenyl)-1H-pyrazole-4-carbaldehyde derivatives (4a-4j) and (Z)-2-((3-(5- Substituted benzofuran-2-yl)-1-p-substituted -1H-pyrazol-4-yl) methylene)-2, 3-dihydro-5, 6-dimethoxyinden-1-one derivatives (5a-j). Among the synthesized compounds, 4a, 4d and 4 h and (5a-5j) were performed for preliminary screening of their analgesic and anti-inflammatory activities at a single dose of 100 mg/kg in mice by acetic acid induced writhing test and carrageenan-induced rat paw edema model respectively. Among the tested compounds, 5d, 5 g and 5 h were found to have higher analgesic activity with% of protection ranging from 50.49–60.53 and the compounds 4d, 4 h and 5d exhibited promising anti-inflammatory activity with% of protection 66.62–72.23.

Schiff bases of 4-Phenyl-2-Aminothiazoles as hits to new antischistosomals: Synthesis, in vitro, in vivo and in silico studies

The treatment of schistosomiasis is based on a single drug, the praziquantel (PZQ), an oral bioavailable and efficient agent which causes minimal side effects. The main concern about this approach, however, is that relying on only one drug to treat a helminthic disease is a dangerous strategy since history shows that pathogens easily evolve to resistant forms. Actually, reports about experimental strains exhibiting low sensibility to PZQ can be found in literature. The search for new antischistosomals, consequently, is urgent. Here we report the synthesis of seventeen Schiff bases of 4-(4-Substituted phenyl)-N-(4-substituted benzylidene)thiazole-2-amines which were tested in vitro and in vivo against Schistosoma mansoni adult worms. Moreover, in silico studies to propose potential macromolecular targets and to predict the oral bioavailability were also performed. The analog GPQF-108 exhibited the best in vitro performance (IC50: 29.4 µM, SI:6.1) associated with promising in vivo activity, with a significant decrease in the adult life forms and oviposition. Oral bioavailability could be impaired by the predicted low water solubility of GPQF-108, although it also exhibited good membrane permeability. The water solubility, however, could be improved by decreasing the particles size. Serine/Threonine- and Tyrosine Kinases, Carbonic Anhydrase, Tyrosine Phosphatase and Arginase were predicted as potential macromolecular targets through which the GPQF-108 could be acting against the helminth. This class of compounds exhibited an interesting initial therapeutic profile with the advantage of being chemically diverse from the PZQ and be easily synthesized from commercial reagents which could lead to low-cost drugs. These aspects make this class of compounds interesting hits to be explored against schistosomiasis.

Rigid indolocarbazole donor moiety for highly efficient thermally activated delayed fluorescent device

A new rigid donor moiety, namely, triphenyl-substituted indolocarbazole for thermally activated delayed fluorescence (TADF) materials is reported. Based on this donor, two novel TADF emitters 5-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho [3,2,1-de]anthracen-7-yl)-6,11,12-triphenyl-5,11-dihydroindolo [3,2-b]carbazole (TDBA-TPDICz) and 5-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-6,11,12-triphenyl-5,11-dihydroindolo [3,2-b]carbazole (TRZ-TPDICz) are synthesized and evaluated as TADF emitters. The phenyl substitutions at 6, 12-positions of donor moiety increase the steric hindrance between the donor and the acceptor resulting in increase in dihedral angle between them. As a consequence, the change in the TADF properties of these emitters are analyzed by photophysical, electrochemical properties and compared with the analogs reference material 5-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-11-phenyl-5,11-dihydroindolo [3,2-b]carbazole (TRZ-pIC). Further, the TADF device fabricated with TDBA-TPDICz shows the deep blue color CIE coordinates of (0.14, 0.14) with a maximum external quantum efficiency (EQE) of 16.9% and maximum current efficiency (CE) of 21.4 cd/A. Meanwhile, the device using TRZ-TPDICz emitter achieve a maximum EQE of 30.3% and a maximum CE of 77.4 cd/A at green color CIE coordinates of (0.25, 0.53). This result is superior than the TRZ-pIC reference material.

In Silico Analysis, Synthesis, and Biological Evaluation of Triazole Derivatives as H1 Receptor Antagonist.

Histamine, a biological amine, is considered as a principal mediator of many pathological processes regulating several essential events in allergies and autoimmune diseases. Numerous derivatives have been developed that strive with histamine at the H1 receptor and prevent binding of histamine at the H1 receptor, thereby preventing allergic reactions. Molecules containing a triazole ring fused with six-membered ring systems are found to possess broad applications in the field of medicine and industry. The present study is an attempt to characterize the impact of the nature of the substituent introduced at 5 positions of the-4H-1,2,4-triazole-3-thiol on their capacities to bind with the H1 receptor. Molecular docking (PDB ID: 3RZE) revealed that synthesized derivatives and target proteins were actively involved in binding with Tyr-108, Thr-112, Ala-216, and Phe-432 subunits. A pharmacophore model, new 5-(4-substituted phenyl)-4-(phenylamino)-4-H-1,2,4-triazole-3- thiols (5a-5h) were designed and evaluated for H1-blocking activity using isolated segments from the guinea pig ileum. According to in silico analysis, all the compounds have a topological polar surface area (TPSA) less than 140 Å squared, so they tend to easily penetrate cell membranes. The results show that most of the compounds are non-inhibitors of CYP450 substrates that play a fundamental role in drug metabolism. Compounds 5d (50.53±12.03), 5h (50.62±12.33) and 7a (55.07±12.41) are more active than others. Finally, these derivatives were screened for H1 receptor antagonist activity using guinea pig ileum, taking chlorpheniramine maleate as a standard. Most of the compounds were found to possess better antihistamine activity.

Experimental and theoretical approaches to the study of the reactivity and mechanism of the substitution of phenyl 1‐(2,4‐dinitronaphthyl) ether with anilines derivatives

AbstractReactions of aniline derivatives in dimethyl sulfoxide with phenyl 1‐(2,4‐dinitronaphthyl) ether yield aryl 1‐(2,4‐dinitronaphthyl) amine, which results in substitution of the phenoxy groups at the naphthyl ipso carbon atom. Rate constants were measured spectrophotometrically, and reaction proton transfer was rate limiting. The values of the rate coefficients indicate a rate‐limiting proton transfer mechanism with significant substituent effects. The calculated activation parameters were of regular variation with substituents in 4‐ and 3‐position in the aniline nucleophile, and the reaction proceeded through a common mechanism. Hammett's reaction constant showed that the reaction rate constants depend on the electron density of the nitrogen atom of aniline derivative, whereas the coefficient value obtained from the Brönsted relation indicated that the reaction was significantly associative and quite zwitterion like. Computational studies of the substitution were carried out based on density functional theory, and theoretical to the experimental agreement was achieved.

15.3% efficiency all-small-molecule organic solar cells enabled by symmetric phenyl substitution

Synergistic optimization of donor-acceptor blend morphologyis a hurdle in the path of realizing efficient non-fullerene small-molecule organic solar cells (NFSM-OSCs) due to the anisotropic conjugated backbones of both donor and acceptor. Therefore, developing a facile molecular design strategy to effectively regulate the crystalline properties of photoactive materials, and thus, enable the optimization of blend morphology is of vital importance. In this study, a new donor molecule B1, comprising phenyl-substituted benzodithiophene (BDT) central unit, exhibits strong interaction with the non-fullerene acceptor BO-4Cl in comparison with its corresponding thiophene-substituted BDT-based material, BTR. As a result, the B1 is affected and induced from an edge-on to a face-on orientation by the acceptor, while the BTR and the acceptor behave individually for the similar molecular orientation in pristine and blend films according to grazing incidence wide angle X-ray scattering results. It means the donor-acceptor blend morphology is synergistically optimized in the B1 system, and the B1:BO-4Cl-based devices achieve an outstanding power conversion efficiency (PCE) of 15.3%, further certified to be 15.1% by the National Institute of Metrology, China. Our results demonstrate a simple and effective strategy to improve the crystalline properties of the donor molecule as well as synergistically optimize the morphology of the all-small-molecule system, leading to the high-performance NFSM-OSCs.

Microwave-Assisted Synthesis of 2-(5-(5-(4-Substituted phenyl)-2-(5-methoxy- 2H-chromen-3-yl)-1H-imidazol-1-yl)alkyl)-1H-benzo[de]isoquinoline- 1,3(2H)-dione Derivatives and their Antimicrobial Activity

A method for the synthesis of several imidazoles containing isoquinoline scaffolds under conventional and microwave irradiation methods. In the microwave irradiation method gives higher yields with in shorter reaction time as compared to conventional heating method, using green solvents and eco-friendly reaction conditions. All the synthesized derivatives were characterized by IR, NMR and Mass spectral analysis. Furthermore, the title compounds were screened for their in vitro antimicrobial activity against bacteria such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumonia as well as fungi such as Aspergillus niger, Aspergillus flavus and Fusarium oxysporum. The compounds 8a, 8d, 8e and 8h exhibited better antimicrobial activity against all organisms.

Synthesis and Properties of Azadipyrromethene‐Based Complexes with Nitrile Substitution

Azadipyrromethene (ADP)‐based complexes have gained interest due to their strong absorption in the visible to near‐IR region and high electron affinity. Attempts to increase their electron accepting properties by electron withdrawing group substitutions have been limited. We previously found that substitution with fluorine at the p‐distal phenyls or at the p‐pyrrolic‐phenylethynyls of ADP do not shift reduction potentials and thus have no effect on electron affinity. This could be because fluorine also acts as pi‐donor, thus, a pi‐acceptor substituent may have a greater impact on the energy levels. To test this hypothesis, we synthesized three new ADP‐based complexes with nitrile substitutions. Cyclic voltammetry shows that the nitrile substitutions indeed anodically shifts the reduction potentials, leading to increased electron affinity. The shift was ≈ 0.3 V for the p‐distal phenyl substitution and 0.16V for the p‐phenylethynyl substitution. Nitrile substitution was also found to improve electron accepting ability and electron mobility in diodes, as compared to the un‐substituted analogues.

Synthesis, Characterization and Anti-inflammatory Activity of 2-(4-chlorobenzyl)-5-(di(5- substituted-1H-indol-3-yl)methyl)-6-(4-substituted phenyl)imidazo[2,1-b][1,3,4]thiadiazoles

In present study, the anti-inflammatory potential of a series of 2-(4-chlorobenzyl)-5-(di(5-substituted- 1H-indol-3-yl)methyl)-6-(4-substituted phenyl)imidazo[2,1-b][1,3,4]thiadiazoles (5a-e) were evuluated after characterizing through 1H NMR, 13C NMR spectral studies. Initial toxicity and anti-inflammatory efficacy of synthesized compounds is evaluated against RAW264.7 macrophages cell line to derive at their IC50 values. Compounds 5a-e are further tested for their anti-inflammatory activity in Swiss albino rats using the 1% carrageenan-induced paw edema model. Compound 5a is taken as the lead compound and is further considered for behavioural evaluations such as stair climbing and motility exercises. Paw edema is analyzed at time intervals of 0, 1, 2, 3, 4 and 24 h and stair climbing and motility tests are surveyed after 24 h of exposure to the test compound. The results of present study show that the compound 5a significantly reduces the paw thickness by 68% at p < 0.001 and increased the stair climbing (1.5 folds) and motility (1.6 folds) when compared to the 1% carrageenan rat group. Conclusively the results of present study show that compound 5a exhibits strong anti-inflammatory potential that can be used as a preclinical template for further investigations as an alternative therapy to the current NSAIDs.

Synthesis and Biological Evaluation of Novel Triazolyl-Acridine Derivatives as Cytotoxic Agents

Novel triazolyl-acridine compounds were synthesized in 4 series of 9-(2-(substituted phenyl-1H-1,2,3-triazol-1-yl)ethoxy)acridine, 9-(3-(4-(2-substituted phenyl)-1H-1,2,3-triazol-1-yl)propoxy) acridine, N-(2-(4 substituted phenyl-1H-1,2,3-triazol-1-yl)ethyl)acridin-9-amine and N-(3-(4-(substituted phenyl)-1H-1,2,3-triazol-1-yl)propyl)acridin-9-amine using appropriate synthetic procedures and screened for cytotoxic activity. The structures of all synthesized compounds were confirmed by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance and mass spectroscopy and these compounds were assayed in vitro for cytotoxic activity against MCF-7 (human breast adenocarcinoma cell line) and HT-29 (human colon adenocarcinoma cell line) cells. Tested compounds showed better cytotoxic activities in terms of IC50 value against MCF-7 and HT-29 cells. Methyl substituted compound MPP-9 exhibited excellent sensitivity with IC50 value 1 and 2 µM, against MCF-7 and HT-29, respectively. Unsubstituted MPP-1 and chloro-substituted MPP-2 and MPP-5 also exhibited good IC50 value ranges from 2-4 µM against both cell lines. These compounds were active at micro molar concentrations. Data study revealed that synthesized compounds are promising leads for future as cytotoxic agents.

Novel sulindac derivatives: synthesis, characterisation, evaluation of antioxidant, analgesic, anti-inflammatory, ulcerogenic and COX-2 inhibition activity

A new series of N′-(substituted phenyl)-2-(1-(4-(methylsulfinyl) benzylidene)−5-fluoro-2-methyl-1H-inden-3-yl) acetohydrazide derivatives (1 – 25) were prepared in good yields in an efficient manner. All the compounds were fully characterised by the elemental analysis and spectral data. Synthesised compounds were evaluated for antioxidant activity by DPPH method. Compounds 7 (R = 3-methoxyphenyl), 3 (R = 4-dimethylaminophenyl) and 23 (R = 2,4,5-trimethoxy phenyl) substitutions were found to be having highly potent antioxidant activity. Compound 3, with para dimethylaminophenyl substitution was found to be having highest antioxidant activity. It was further evaluated in vivo for various analgesic, anti-inflammatory, ulcerogenic and COX-2 inhibitory activity in different animal models. Lead compound 3 was found to be significant anti-inflammatory and analgesic agent. It was also evaluated for ulcerogenic activity and demonstrated significant ulcerogenic reduction activity in ethanol and indomethacin model. The LD50 of compound 3 was found to be 131 mg/kg. The animals treated with compound 3 prior to cisplatin treatment resulted in a significant reduction in COX-2 protein expression when compared to cisplatin-treated group. Sulindac derivative with para dimethylaminophenyl substitution was found to be the most potent antioxidant, anti-inflammatory and analgesic agent as well as with significant gastric sparing activity as compared to standard drug sulindac. Compound 3 significantly downregulated liver tissue COX‐2 gene expression.

Investigation of redox mechanism and DNA binding of novel 2-(x-nitrophenyl)-5-nitrobenzimidazole (x = 2, 3 and 4)

The present study describes the investigation of the binding modes of potential anti-cancerous nitrophenyl derivatives of 2-(x-nitrophenyl)-5-nitrobenzimidazole with calf thymus DNA. The -2-(x-nitrophenyl)-5-nitrobenzimidazoles under investigation differ only in position x of nitro group in nitrophenyl substituent relative to benzimidazole moiety leading to 1-NPNB (x = 2), 2-NPNB (x = 3) and 3-NPNB (x = 4). The DFT calculations predicted that derivatives were electrochemically reducible which was then confirmed by cyclic voltammetry. In cyclic voltammetry, the second reversible peak was dependent on first irreversible reduction. This revealed that electrochemical irreversible process was governed by some other process which was then followed by reversible second electron transfer. Thus, ECE (electron transfer leading to coupled chemical reaction followed by another electron transfer process) mechanism was attributed for electrochemical reduction. Experimental results based on UV–Vis spectroscopy vaguely showed intercalation of 1-NPNB, 2-NPNB and 3-NPNB into DNA which was assisted by cyclic voltammetry. However, thermal melting and florescence spectroscopy unambiguously established intercalation for all three compounds. Molecular docking analysis ascertained in pocket stacking of 5-nitrobenzimidazole moiety in 1-NPNB and 2-NPNB while nitro phenyl substitution in 3-NPNB stacks between DNA base pair during intercalation which was in agreement with DFT computed molecular geometry. Therefore, the relative positions of nitro group and 5-nitrobenzimidazole moieties in 2-(x-nitrophenyl)- 5-nitrobenzimidazole influenced the DNA binding pattern of compounds during intercalation. The cytotoxicity of these compounds was comparable to standard drug doxorubicin against both cancerous (MCF-7) and normal (MCF-10A) breast cells which depicts their anti-cancerous potential.

A new series of thiazolyl pyrazoline derivatives linked to benzo[1,3]dioxole moiety: Synthesis and evaluation of antimicrobial and anti-proliferative activities

2-(5-(Benzo[d][1,3]dioxol-5-yl)-3-(naphthalen-1-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-substituted phenyl)thiazole (7) and thiazole derivatives (9) were synthesized via reaction of 4,5-dihydro-1H-pyrazoles (5a,b) with substituted phenacyl bromide and a number of α-halo-compounds respectively. Also, (E)-2-(5-(benzo[d][1,3]dioxol-5-yl)-3-(naphthalen-1-yl)-4,5 dihydro-1H-pyrazol-1-yl)-4-methyl-5-(substituted phenyldiazenyl)thiazole (11) were prepared through reactions of carbothioamide (5a,b) with hydrazonoyl halides. In addition, thioamides (5a–b) were used as starting materials for preparation of thiazoles (12a–b) and benzylidene thiazoles (13a–b). Most of synthesized compounds show interesting biological properties as antimicrobial and antiproliferative activities, the results of minimum inhibitory concentration showed that pyrazole derivative 7c (MIC: 0.23 mg/mL) showed better results when compared with 11c and 12a (MIC: 0.1–0.125 mg/mL) as obtained from their MIC values. On the other hand, 2-(5-(benzo[d][1,3]dioxol-5-yl)-3-(naphthalen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-(4-chlorophenyl) thiazole (7c) can be considered as the most promising anti-proliferative agent against HCT-116 cancer cells owing to its notable inhibitory effect on HCT-116 cells with an IC50 value of 6.19 µM.

Effect of Substitution for Insertion of CO2 into Epoxides and Aziridines: An Ab Initio Study

The insertion of CO2 into epoxides and aziridines has been studied using density functional theory (B3LYP) and ab initio (MP2) methods, and the effect of substitution for the two reactions are further explored. It is found that the reactivity of epoxides and aziridines are similar, and insertion of CO2 proceeds through a concerted mechanism. The substitutions of methyl and phenyl does not change the reaction mechanism, but the transition state for the substitution on the attacking position becomes loose with a lower free energy barrier. The substitutions of methyl and phenyl decrease the free energy barrier, with phenyl substitution having a greater affect. The results also show that the free energy barriers for the insertions of CO2 into aziridines are ~10kcalmol−1 lower than the corresponding reactions of CO2 with epoxides.

Tetrahydroquinoline units in flexible heteroarotinoids (Flex-Hets) convey anti-cancer properties in A2780 ovarian cancer cells

SHetA2 (NSC 721689), our lead Flex-Het anti-cancer agent, consists of a thiochroman (Ring A) and a 4-nitrophenyl (Ring B) linked by a thiourea bridge. In this work, several series of new analogs having a tetrahydroquinoline (THQ, Ring A) unit connected by a urea or thiourea linker to a 4-substituted phenyl (Ring B) have been prepared and evaluated relative to SHetA2 in terms of binding affinity with mortalin and inhibition of A2780 ovarian cancer cells. Six of the derivatives equaled or exceeded the efficacy shown by SHetA2. Compounds 1a-d (series 1), lacking a methyl on the Ring A nitrogen and the gem-dimethyls on the adjacent carbon, showed only weak activity. Salt 2, the quaternized N,N-dimethyl iodide salt analog of 1a, also possessed very modest growth inhibition in the cell line studied. Series 3 compounds, which had a C3 ketone and an N-methyl replacing the sulfur in Ring A, were most successful. Compound 3a [Ring A = 1,2,2,4,4-pentamethyl-3-oxo-1,2,3,4-tetrahydroquinolin-6-yl; urea linker; Ring B = 4-nitrophenyl] had slightly lower potency (IC50 3.8 μM), but better efficacy (94.8%) than SHetA2 (IC50 3.17 μM, efficacy 84.3%). In addition, 3c and 3d [urea and thiourea linkers, respectively; Ring B = 4-(trifluoromethyl)phenyl] and 3e and 3f [urea and thiourea linkers, respectively; Ring B = 4-(trifluoromethoxy)phenyl] were also evaluated since these agents possessed electron-withdrawing groups with H-bonding capability. All displayed good activity. Compounds 3c and 3e showed improvement in both potency and efficacy compared to SHetA2. In general, when the linker group between Rings A and B was a urea, efficacy values slightly exceeded those with a thiourea linker in the carbonyl-containing THQ systems 3a-g. In contrast, when Ring A possessed the 1,2,2,4,4-pentamethyl-3-hydroxytetrahydroquinolin-6-yl unit (4a-f, series 4), very modest potency and efficacy was observed. Model compound 5, an exact N-methyl THQ analog of SHetA2, demonstrated less potency (IC50 4.5 μM), but improved efficacy (91.7%). Modeling studies were performed to rationalize the observed results.

Effect of chemical structure of hydrazide compounds on nucleation effect in isotactic polypropylene

A series of hydrazide compounds were synthesized and employed as nucleating agents for isotactic polypropylene (iPP). The effect of different structures of hydrazide compounds on the crystallization and melting behaviour of iPP was studied by differential scanning calorimetry (DSC). The results demonstrate that almost all nucleating agents are α-nucleating agents, some of which are highly efficient nucleating agents. In the case of the same substituent, the greater the number of hydrazide groups, the better the nucleation effect. The crystallization peak temperature (Tc) of iPP nucleated with dihydrazide is 3–4 °C higher than that of monohydrazide. When the substituent of the dihydrazide compound is hydrogen, ethyl and nonyl, their nucleating ability is relatively weak, but in the state of phenyl and cyclohexyl substitution, the Tc of iPP nucleated with dihydrazide nucleating agent is 8.5 °C than pure iPP. When the intermediate group of the dihydrazide compound is a long-chain alkyl, a phenyl, a cyclohexyl, and a naphthyl group, the phenyl group and the cyclohexyl group still exhibit an excellent effect, the Tc of nucleated iPP is raised by about 10 °C.

Synthesis, optical, and thermal properties of 2,4,6-tris(4-substituted phenyl)pyrylium tosylates and triflimides

A group of five 2,4,6-tris(4-substituted phenyl)pyrylium tosylates were synthesized in one-pot reaction from para-substituted benzaldehyde and para-substituted acetophenones using tosic acid as a condensing agent. The tosylate salts were converted to the corresponding triflimide salts by metathesis reactions. Chemical structures, as well as optical spectroscopic and thermal properties of these salts were studied using pertinent experimental techniques. Trimethyl- and trihalo-substituted pyrylium salts emitted strong blue light with peaks in the 456 nm–479 nm range and trimethoxy-pyrylium salts emitted intense green light with maxima around 526 nm in acetonitrile solution. Quantum yields of the solutions were rather low, but the salts were also fluorescent in the solid state. Acetonitrile solution of trichloro-substituted pyrylium triflimide showed significant spectral line narrowing and fluorescence lifetime shortening under intense excitation, and laser action with minimal feedback. The salts have low melting transitions compared to the corresponding –BF4 salts, and their thermal stability is excellent with decomposition temperature in the 268–402 °C range in nitrogen.

Microwave‐Assisted Synthesis and Biological Evaluation of Some New Pyrazolothiazoles via a Multicomponent Approach

AbstractA series of new pyrazolothiazole hybrids were designed and synthesized by the microwave‐assisted multicomponent reaction of thiosemicarbazide, 3‐(furan‐2‐yl)‐1‐(pyridin‐2‐yl)prop‐2‐en‐1‐one and 1‐(pyridin‐2‐yl)‐3‐(thiophen‐2‐yl)prop‐2‐en‐1‐one with substituted 2‐bromoacetophenones. Structures of all the synthesized compounds were in good agreement with their spectral (FTIR, 1H & 13C NMR, Mass) and analytical data (CHN analysis). The target compounds were screened for their in vitro cytotoxic activity by testing against human adenocarcinoma (A549), cervical cancer (HeLa), human neuroblastoma (SK−N‐SH) and human prostate cancer (DU‐145) cell lines. From the in vitro results, it was found that the compound derived from p‐ NO2 phenyl (4 h) has potent activity against HeLa cell line with IC50 value 9.97 ± 0.05 μM. Also, the compounds having p‐OCH3 phenyl (4 c), phenyl (4 i), and p‐Cl phenyl (4 j) substitutions exhibited significant activity against HeLa cell line with IC50 values 19.78 ± 0.03 μM, 18.47 ± 0.01 μM and 15.61 ± 0.06 μM respectively.