Para Position Of Phenyl Ring Research Articles

Design, Synthesis, Biological and Computational Analysis of Isatin-based bis-Thiourea Analogues as Anti-diabetic and Anti-nematode Agents

A new series of isatin derivatives were synthesized, characterized by 1HNMR, 13CNMR and HREI-MS, and screened for α-glucosidase and alpha amylase inhibition. All the analogues were found to be dual inhibitors and showed good inhibitory potentials with IC50 values ranging from 5.28 ± 0.10 to 38.66 ± 0.30 µM (against alpha-amylase), and 5.45 ± 0.10 to 39.25 ± 0.50 µM (against alpha-glucosidase), as compared to the standard drug acarbose (IC50 = 11.12 ± 0.15 and 11.29 ± 0.07 µM, respectively). The most potent inhibitor among the series was analogue 24 (IC50 = 5.28 ± 0.10 for alpha-amylase and IC50 = 5.46 ± 0.10 µM for alpha-glucosidase), which has a nitro group attached at the meta-position of the phenyl ring A and the para position of phenyl ring B. Structure-activity relationship has been established mainly based on the position, nature and number of the substituent(s) attached to the phenyl ring. To investigate the binding interaction of the potent analog with the active site of an enzyme, molecular docking studies were carried out. To study the drug-likeness properties, the ADME study was also carried out. The most active compounds engage most of the amino acids composing the active site and display maximum interactions. These interactions majorly include formation of strong hydrogen bonds, which might be due to the presence of highly electronegative heteroatoms on aromatic rings. All the analogues were also tested for in vivo anti-nematodal activity against C. elegans to assess their cytotoxicity in comparison to the reference Levamisole. The cytotoxicity profile demonstrated that analogues 2, 7, 20 and 22 displayed minimum cytotoxicity at every concentration.

Combined computational and synthetic strategies for the development of potent pyrazolo-pyridine derivatives as anticancer agents

PI3K comprise a group of lipid kinases mainly made up of three classes and have a particular role in signal transduction. The aberration of class IA PI3K is most frequently shown in cancer. The computation techniques have been applied for the identification of potent compounds. This involved the generation of a library of novel compounds (2700) through R-group enumeration study. The screening process utilized a combination of pharmacophore-based virtual screening and various docking algorithms, leading to the discovery of ten novel compounds. The docking studies against PI3K kinase highlighted MSA6 and MSA7 as the most promising compounds, with docking scores of -9.03 and -9.0 kcal/mol, respectively. Results of docking studies of all derivatives confirmed satisfactory binding mode of the compounds within the active site of the target protein PI3K kinase. The screened pyrazolo-pyridine derivatives (MSA1-MSA10) were synthesized and evaluated as anti-cancer agents against NSCLC using A549 cell line. MSA6 showed the dose dependent enhancement in ROS production at concentration of 10 and 20 µM in A549 cells. MSA6 triggered caspase 3 cleavage in lung cancer cells in a dose-dependent manner. MSA6 treatment at 10 and 20 µM levels boosted NF-κβ expression in the cytoplasm while decreasing it in the nucleus, as demonstrated by flow cytometry with an anti-NF-κβ antibody. The modulation of PI3K activity have been observed at 10 µM and 20 µM concentration of MSA6. A549 cells treated with MSA6 with 20 µM showed significant reduction in wound healing in cancerous cell. A549 cells treated with 20 µM showed significantly reduction in number of colonies compared to control group. Compound MSA6 having a methyl group at the para position of phenyl ring at imine carbon and phenyl ring substitution at nitrogen of pyrazole ring exhibited remarkable growth inhibitory activity with IC50 value of 49.23 μM. Based on the above results, pyrazolo-pyridine derivatives can be used for the further development of novel PI3K kinase inhibitors as anticancer agents.

Promotion of Catalytic Oxygen Reduction Reactions: The Utility of Proton Management Substituents on Cobalt Porphyrins.

Three ABAB-type cobalt meso-tetraarylporphyrins with fluorine (F-CoPor), acetic acid (AC-CoPor), and cyanoacetic acid (CN-CoPor) groups at the para-positions of phenyl rings at the 10,20-positions are synthesized and evaluated as catalysts for oxygen reduction reactions (ORRs). In density functional theory calculations, the frontier molecular orbitals of these complexes were found to be stabilized relative to model complexes with electron-withdrawing atoms or moieties on the meso-aryl rings. Electrochemical measurements suggest that electrodes with CN-CoPor (CN-CoPor/C) exhibit the most positive ORR potential values and the highest limiting current density in both acidic and alkali electrolytes, while the F-CoPor/C electrocatalyst exhibits extremely low ORR performance. The electron transfer numbers for the electrocatalysts are more than 3.0, indicating that a mixture of 2- and 4-electron transfer pathways occurs. The results demonstrate that coupling the hydrogen bonding properties and electron-withdrawing abilities through rational design of the substituent at the meso-position is an efficient way to modify the ORR performance.

Evaluation of N-aryl-β-alanine derivatives as anticancer agents in triple-negative breast cancer and glioblastoma in vitro models

Synthesis of β-amino acid derivatives containing hydrazone and azole moieties is described. For this purpose, the appropriate hydrazide was treated with aromatic aldehydes, ketones and phenyl iso(thio)cyanates to obtain the desired outcome. The synthesized target compounds were evaluated for their anticancer properties. The assay displayed 3,3′-((2,6-diethylphenyl)azanediyl)bis(N′-(benzylidene)propanehydrazide) to possess the convincing anticancer effect against triple-negative breast cancer cells in vitro. To further study the anticancer properties of compounds containing a hydrazone moiety in breast cancer, series of previously and newly prepared dihydrazones were investigated. It was determined that derivatives with the bis(N′-(4-bromobenzylidene) fragment in the structure are exclusively cytotoxic to cancer cells. The most active compounds against both cell lines were those containing electron withdrawing 4-BrPh or 4-ClPh moieties, together with either chlorine, bromine or iodine groups in para position of phenyl ring. Selected two representative compounds showed migrastatic activity in MDA-MB-231 cell line, where both of them reduced the growth of breast cancer and glioblastoma cell 3D cultures and inhibited cell colony formation. 2009 Elsevier Ltd. All rights reserved.

Molecular docking analysis of selected pyrimidine derivatives with human cyclin-dependent kinase 2.

A series of pyrimidine were synthesized, characterized and evaluated for their antioxidant properties using the human cyclin-dependent kinase-2 protein model. Data shows that the pyrimidine derivatives (compound ID 4G) with para fluoro groups substitution at phenyl ring attached to the 4th position (IC50: 98.5µg/ml), compound 4B bearing hydroxy group at para position of phenyl ring (IC50: 117.8 µg/ml) have significant antioxidant activity. Docking data infer that compounds 4c, 4a, 4h and 4b possess binding energy (-7.9, -7.7, -7.5 and -7.4 kcal.mol-1) with 1HCK (PDB ID) receptor.

Design, synthesis and antimicrobial activity of novel 2-aminothiophene containing cyclic and heterocyclic moieties

One of the major challenges in the community and healthcare was an impedance of pathogenic bacteria to antibiotics. This work developed 2-aminothiophene derivatives as novel antimicrobial agents. Various 2-aminothiophene derivatives (3a–f, 5a–c, 6a, b, 7, 8a, b and 9) with cyclic and heterocyclic moieties at 5-position were synthesized, and characterized using NMR, IR, and mass spectroscopic techniques. The newly synthesized compounds were evaluated for their antimicrobial activity against bacteria S. pneumoniae, B. subtilis, P. aeruginosa, E. coli, and fungi A. fumigatus, S. mracemosum, G. candidum, C. albicans. Compound 3a with OH group at para position of phenyl ring exhibited significant antibacterial activity stronger than that of the drug standards Ampicillin and Gentamicin. Compound 6b possess pyrazole ring and compound 9 bearing pyridine ring showed promising antifungal activity compare to the standard drug Amphotericin B. The remaining compounds exhibited good to moderate inhibitory activities. In summary, the results suggest that the compounds from 2-aminothiophene derivatives can be used as antimicrobial agents.

Effect of Methoxy Side Groups on the Crystal Structures of a Series of Syndiotactic Polymethoxystyrenes as Studied by the X-ray Diffraction Data Analysis

The crystal structures have been elucidated for a series of novel syndiotactic polymethoxystyrenes (OMe-SPSs) having −OCH3 groups at the ortho-, meta-, or para-positions of phenyl rings on the basi...

An Unconventional trans - exo -Selective Cyclization of Alkyne-Tethered Cyclohexadienones Initiated by Rhodium(III)-Catalyzed C–H Activation via Insertion Relay

Different from the established trans-endo-selective cyclization of alkyne-tethered electrophiles that involve an E/Z isomerization process, herein, the authors present a novel strategy to allow tra...

Synthesis and bioactivity of phenyl substituted furan and oxazole carboxylic acid derivatives as potential PDE4 inhibitors.

In this present study, a series of 5-phenyl-2-furan and 4-phenyl-2-oxazole derivatives were designed and synthesized as phosphodiesterase type 4 (PDE4) inhibitors. Invitro results showed that the synthesized compounds exhibited considerable inhibitory activity against PDE4B and blockade of LPS-induced TNF-α release. Among the designed compounds, Compound 5j exhibited lower IC50 value (1.4μM) against PDE4 than parent rolipram (2.0μM) in invitro enzyme assay, which also displayed good invivo activity in animal models of asthma/COPD and sepsis induced by LPS. Docking results suggested that introduction of methoxy group at para-position of phenyl ring, demonstrated good interaction with metal binding pocket domain of PDE4B, which was helpful to enhance inhibitory activity.

1,2,3-Triazoles based 3-substituted 2-thioquinoxalines: Synthesis, anti-bacterial activities, and molecular docking studies

Abstract New 1,2,3-triazoles based on 3-Substituted 2-thioquinoxalines were synthesized via a copper-catalyzed click reaction. The new 1,2,3-triazoles were screened for their in vitro antibacterial activities and were subjected to molecular docking studies. The starting materials included, 3-substituted-2-propargylthioquinoxalines were prepared from 2,3-dichloroquinoxaline, aliphatic amines, sodium sulfide, and propargyl bromide. The click of 2-propargythioquinoxalines with aryl azides catalyzed by copper(II) salen complex afforded novel 1,2,3-triazole-linked thioquinoxalines derivatives. The use of salen copper(II) complex as a catalyst, increased the reaction rate and reduced the loading of the toxic copper species. Results obtained from the in vitro anti-bacterial activities of the synthesized compounds revealed that compounds 7e, 7g, and 7k are active against Bacillus subtilis and Micrococcus luteus bacteria. Furthermore, in silico molecular docking results stipulated a sign of good correlation between experimental activity and calculated binding affinity. Docking studies proved 7e as the most potent compound. In addition, the binding maps exhibited activities that may attribute to the existence of electron donating and lipophilic group at para position of phenyl ring and hydrophobic interactions and hydrogen bond with the protein active sites.

Solvent and Substituents Effect on the UV/Vis Absorption Spectra of Novel Acidochromic 2-Aminothiazole Based Disperse Mono Azo Dyes

The effect of solvent atmosphere on the electronic absorption properties of 2-aminothiazole based monoazo disperse dyes are studied. The synthesized monoazo dyes with different substituents on the para position of phenyl ring led to changes in the absorption properties of these dyes. Further, the positive solvatochromism data was evaluated to get the excited and ground state dipole moment ratio of the dyes. The Kamlet-Taft and Catalan polarity scales were employed wherein the solvent basicity and dipolarity is responsible for the bathochromic shift with increase in solvent polarity. The free amino group in the dyes made it responsive towards protonation by trifluoroacetic acid. The acidochromic behavior of the dyes was studied and D1, D3, and D4 exhibited major color change to longer wavelength with emergence of a new red shifted absorption band at 556 nm, 580 nm, and 540 nm, respectively, in their absorption spectra. Thus with help of simple UV-Vis absorption studies, we have studied the intermolecular interactions of the 2-aminothiazole based mono azo acidochromic probe.

Toward of Safer Phenylbutazone Derivatives by Exploration of Toxicity Mechanism.

A drug design for safer phenylbutazone was been explored by reactivity and docking studies involving single electron transfer mechanism, as well as toxicological predictions. Several approaches about its structural properties were performed through quantum chemistry calculations at the B3LYP level of theory, together with the 6-31+G(d,p) basis sets. Molecular orbital and ionization potential were associated to electron donation capacity. The spin densities contribution showed a preferential hydroxylation at the para-positions of phenyl ring when compared to other positions. In addition, on electron abstractions the aromatic hydroxylation has more impact than alkyl hydroxylation. Docking studies indicate that six structures 1, 7, 8 and 13–15 have potential for inhibiting human as well as murine COX-2, due to regions showing similar intermolecular interactions to the observed for the control compounds (indomethacin and refecoxib). Toxicity can be related to aromatic hydroxylation. In accordance to our calculations, the derivatives here proposed are potentially more active as well safer than phenylbutazone and only structures 8 and 13–15 were the most promising. Such results can explain the biological properties of phenylbutazone and support the design of potentially safer candidates.

Cytotoxic, DNA Cleavage and Pharmacokinetic Parameter Study of Substituted Novel Furan C-2 Quinoline Coupled 1, 2, 4-Triazole and Its Analogs.

Furan, quinoline and triazoles are known for their wide spectrum biologically active molecules. A series of novel furan C-2 quinoline and 1, 2, 4-triazole (FQT) coupled hybrids were designed and synthesized to evaluate for their DNA cleavage and cytotoxic studies.In this work we describe the synthesis and biological evaluation of furan C-2 quinoline coupled triazoles exposed for cytotoxic and DNA cleavage study.The electrophoretic DNA cleavage studies on λ-DNA (Eco-RI/Hinda-III double digest) using agarose gelelectrophoresis and the cytotoxic activity were carried out by MTT assay method.The results revealed that, the molecules 7(a-o) did cleave the DNA completely with no trace of fragments at 100 µg concentration, on the other hand, cytotoxic assay was achieved by two different human cancer cell lines (melanoma cell line-A375 and breast cancer cell line MDA-MB 231). Among the synthesized compounds 7a, 7b, 7c and 7k exhibited potent cytotoxic activity with IC50 values ranging from 2.9, 4.0, 7.8 and 5.1 µg/ml against A375 and 6.2, 9.5, 11.3 and 7.3 µg/ml against, MDA-MB 231, respectively.In synthesized compounds 7(a-o) exhibited complete DNA cleavage at 100 µg/ml and the compounds 7a, 7b, 7c and 7k showed very less cytotoxic in nature. The structure activity relationship revealed that, the presence of halogen group/atoms at para position of phenyl ring remarkably enhanced the DNA cleavage and cytotoxic activities among the synthesized compounds.

Synthesis and Structure-Activity Relationships of (-)-cis-N-Normetazocine-Based LP1 Derivatives.

(−)-cis-N-Normetazocine represents a rigid scaffold able to mimic the tyramine moiety of endogenous opioid peptides, and the introduction of different N-substituents influences affinity and efficacy of respective ligands at MOR (mu opioid receptor), DOR (delta opioid receptor), and KOR (kappa opioid receptor). We have previously identified LP1, a MOR/DOR multitarget opioid ligand, with an N-phenylpropanamido substituent linked to (−)-cis-N-Normetazocine scaffold. Herein, we report the synthesis, competition binding and calcium mobilization assays of new compounds 10–16 that differ from LP1 by the nature of the N-substituent. In radioligand binding experiments, the compounds 10–13, featured by an electron-withdrawing or electron-donating group in the para position of phenyl ring, displayed improved affinity for KOR (Ki = 0.85–4.80 μM) in comparison to LP1 (7.5 μM). On the contrary, their MOR and DOR affinities were worse (Ki = 0.18–0.28 μM and Ki = 0.38–1.10 μM, respectively) with respect to LP1 values (Ki = 0.049 and 0.033 μM). Analogous trends was recorded for the compounds 14–16, featured by indoline, tetrahydroquinoline, and diphenylamine functionalities in the N-substituent. In calcium mobilization assays, the compound 10 with a p-fluorophenyl in the N-substituent shared the functional profile of LP1 (pEC50MOR = 7.01), although it was less active. Moreover, the p-methyl- (11) and p-cyano- (12) substituted compounds resulted in MOR partial agonists and DOR/KOR antagonists. By contrast, the derivatives 13–15 resulted as MOR antagonists, and the derivative 16 as a MOR/KOR antagonist (pKBMOR = 6.12 and pKBKOR = 6.11). Collectively, these data corroborated the critical role of the N-substituent in (−)-cis-N-Normetazocine scaffold. Thus, the new synthesized compounds could represent a template to achieve a specific agonist, antagonist, or mixed agonist/antagonist functional profile.

Cytotoxic, DNA Cleavage and Pharmacokinetic Parameter Study of Substituted Novel Furan C-2 Quinoline Coupled 1, 2, 4-Triazole and Its Analogs.

Background:Furan, quinoline and triazoles are known for their wide spectrum biologically active molecules. A series of novel furan C-2 quinoline and 1, 2, 4-triazole (FQT) coupled hybrids were designed and synthesized to evaluate for their DNA cleavage and cytotoxic studies.Objectives:In this work we describe the synthesis and biological evaluation of furan C-2 quinoline coupled triazoles exposed for cytotoxic and DNA cleavage study.Methods:The electrophoretic DNA cleavage studies on λ-DNA (Eco-RI/Hinda-III double digest) using agarose gelelectrophoresis and the cytotoxic activity were carried out by MTT assay method.Results:The results revealed that, the molecules 7(a-o) did cleave the DNA completely with no trace of fragments at 100 µg concentration, on the other hand, cytotoxic assay was achieved by two different human cancer cell lines (melanoma cell line-A375 and breast cancer cell line MDA-MB 231). Among the synthesized compounds 7a, 7b, 7c and 7k exhibited potent cytotoxic activity with IC50 values ranging from 2.9, 4.0, 7.8 and 5.1 µg/ml against A375 and 6.2, 9.5, 11.3 and 7.3 µg/ml against, MDA-MB 231, respectively.Conclusion:In synthesized compounds 7(a-o) exhibited complete DNA cleavage at 100 µg/ml and the compounds 7a, 7b, 7c and 7k showed very less cytotoxic in nature. The structure activity relationship revealed that, the presence of halogen group/atoms at para position of phenyl ring remarkably enhanced the DNA cleavage and cytotoxic activities among the synthesized compounds.

5-Substituted 2-benzylidene-1-tetralone analogues as A1 and/or A2A antagonists for the potential treatment of neurological conditions

Adenosine A1 and A2A receptors are attracting great interest as drug targets for their role in cognitive and motor deficits, respectively. Antagonism of both these adenosine receptors may offer therapeutic benefits in complex neurological diseases, such as Alzheimer’s and Parkinson’s disease. The aim of this study was to explore the affinity and selectivity of 2-benzylidene-1-tetralone derivatives as adenosine A1 and A2A receptor antagonists. Several 5-hydroxy substituted 2-benzylidene-1-tetralone analogues with substituents on ring B were synthesized and assessed as antagonists of the adenosine A1 and A2A receptors via radioligand binding assays. The results indicated that hydroxy substitution in the meta and para position of phenyl ring B, displayed the highest selectivity and affinity for the adenosine A1 receptor with Ki values in the low micromolar range. Replacement of ring B with a 2-amino-pyrimidine moiety led to compound 12 with an increase of affinity and selectivity for the adenosine A2A receptor. These substitution patterns led to enhanced adenosine A1 and A2A receptor binding affinity. The para-substituted 5-hydroxy analogue 3 behaved as an adenosine A1 receptor antagonists in a GTP shift assay performed with rat whole brain membranes expressing adenosine A1 receptors. In conclusion, compounds 3 and 12, showed the best adenosine A1 and A2A receptor affinity respectively, and therefore represent novel adenosine receptor antagonists that may have potential with further structural modifications as drug candidates for neurological disorders.

3D QSAR and molecular docking studies of 4-alkoxy- and 4-acyloxy –phenyl ethylene thiosemicarbazone derivatives as tyrosinase inhibitors

Three-dimensional quantitative structural–activity relationship studies were carried out to understand the factors affecting the activity of 4-alkoxy- and 4-acyloxy –phenyl ethylene thiosemicarbazone analogs. The quantitative structural activity relationship model has generated five points Pharmacophore features, having an excellent cross-validated correlation coefficient value (Q 2 = 0.8615), Pearson R (0.9577). This model also exhibited a high value of R 2 (0.9948), F-value (617.8), and lowest SD (0.089). The regression maps were developed on the basis of the best model and suggested aromatic electron withdrawing groups at the para position of phenyl ring which is crucial for Tyrosinase inhibitory activity. Toxicity and drug-likeness of these compounds were estimated by using OSIRIS molecular property explorer tool. The molecular modeling was performed by using Molegro Virtual Docker 2010.4.0. The binding pattern of the best active compound with Tyrosinase active site was analyzed and the residues HIS259, HIS85, His61, His263, VAL283, Glu322, Gly245, and Ala246 were found to have hydrophobic and hydrogen bond interactions.

Design, synthesis, biological evaluation and molecular modelling studies of novel diaryl substituted pyrazolyl thiazolidinediones as potent pancreatic lipase inhibitors

A series of novel diaryl substituted pyrazolyl 2,4-thiazolidinediones were synthesized via reaction of appropriate pyrazolecarboxaldehydes with 2,4-thiazolidinedione (TZD) and nitrobenzyl substituted 2,4-thiazolidinedione. The resulting compounds were screened in vitro for pancreatic lipase (PL) inhibitory activity. Two assay protocols were performed viz., methods A and B using p-nitrophenyl butyrate and tributyrin as substrates, respectively. Compound 11e exhibited potent PL inhibitory activity (IC50=4.81µM and Xi50=10.01, respectively in method A and B), comparable to that of the standard drug, orlistat (IC50=0.99µM and Xi50=3.72). Presence of nitrobenzyl group at N-3 position of TZD and nature of substituent at para position of phenyl ring at C-3 position of pyrazole ring notably affected the PL inhibitory activity of the tested compounds. Enzyme inhibition kinetics of 11e revealed its reversible competitive inhibition, similar to that of orlistat. Molecular docking studies validated the rationale of pharmacophoric design and are in accordance to the in vitro results. Compound 11e exhibited a potential MolDock score of −153.349kcal/mol. Further, the diaryl pyrazolyl wing exhibited hydrophobic interactions with the amino acids of the hydrophobic lid domain. Moreover, the carbonyl group at 2nd position of the TZD ring existed adjacent to Ser 152 (≈3Å) similar to that of orlistat. A 10ns molecular dynamics simulation of 11e–PL complex revealed a stable binding conformation of 11e in the active site of PL (Maximum RMSD≈3Å). The present study identified novel thiazolidinedione based leads with promising PL inhibitory activity. Further development of the leads might result in potent PL inhibitors.

Synthesis, structure characterization, in vitro and in silico biological evaluation of a new series of thiazole nucleus integrated with pyrazoline scaffolds

In the current study, a series of 2,4-disubstituted-1,3-thiazoles linked with pyrazoline scaffolds 3a-o were rationally designed and synthesized. The structures of the title compounds were elucidated by spectroscopic data (UV–Vis, IR, NMR and Mass spectra) and elemental analysis. Single crystal X-Ray diffraction studies revealed that, the compounds 3i and 3k crystallized in monoclinic crystal system with P21/n space group and Z = 4. The molecules 3i and 3k were connected with intermolecular hydrogen bonds N2—H2 … O1, N3H3 … Cl1 and short contacts (CH … π and CCl … π). Intramolecular hydrogen bonds, N3H3 … N5 and C5H5 ….N1 were also existed. The compounds were evaluated for their anticancer activity against A549 and MCF-7 human cancer cell lines and in vitro antimicrobial activity against pathogenic microbial strains. The compounds bearing chloro atom at the para position of phenyl ring A like 3f, 3j and 3k with the IC50: 7.5, 5.0 and 5.0 μM respectively, exhibited better activity than standard drug Cisplatin (IC50: 10.0 μM). In addition, the compounds 3a, 3f, 3j and 3l have exhibited the similar antimicrobial activity as that of standard drug Ciprofloxacin and Fluconazole. Furthermore, to support the biological potency of the compounds, in silico molecular docking studies were carried out against the E. coli MurB (PDB code: 2MBR) and Jnk1 inhibitor (PDB code: 3v3v) enzymes. The various types of interactions between the compounds and amino acid residue of enzymes were also reported.

The effect of meta-substituted or para-substituted phenyl as side chains on the performance of polymer solar cells

Two donor-acceptor alternative copolymers (P1 and P2) with carbazole group as the donor unit and 2,3-diphenylquinoxaline group as the acceptor unit were designed and synthesized by Suzuki polycondensation reaction. Alkoxy groups were linked to meta-position or para-position of phenyl rings, which were attached on the 2,3-position of quinoxaline group to investigate the effect of the alkoxy position at phenyl rings on the resulting polymer optical, electrochemical and photovoltaic properties. GIWAXS experiments revealed that para-substituted polymer P2 possesses closer packing properties in the solid state. The absorption spectra of para-substituted polymer P2 also displayed larger red-shift than that of meta-substituted polymer P1 when it went from solution to the film, which was beneficial to improve the hole mobilities and short circuit current density (Jsc). When used as the donor materials, devices based on P2:PC71BM exhibited a PCE of 3.33%, which was obviously higher than that based on P1:PC71BM. Our results revealed that the slightly structure change of polymer has a significant influence on the photovoltaic properties of polymer solar cells and adopting para-substituted phenyl ring as the side groups gave superior photovoltaic performance in donor materials based on carbazole and quinoxaline.