Skip to main content
  • Research article
  • Open access
  • Published:

Regioselective synthesis of 2-(bromomethyl)-5-aryl-thiophene derivatives viapalladium (0) catalyzed suzuki cross-coupling reactions: as antithrombotic and haemolytically active molecules

Abstract

Background

It is seen that the regioselective functionalizations of halogenated heterocycles play an important role in the synthesis of several types of organic compounds. In this domain, the Suzuki-Miyaura reaction has emerged as a convenient way to build carbon-carbon bonds in synthesizing organic compounds. Some of the most important applications of these reactions can be seen in the synthesis of natural products, and in designing targeted pharmaceutical compounds. Herein, we present the regioselective synthesis of the novel series of 2-(bromomethyl)-5-aryl-thiophenes 3a-i, via Suzuki cross-coupling reactions of various aryl boronic acids with 2-bromo-5-(bromomethyl)thiophene (2).

Results

The synthesized compounds were screened for their haemolytic and antithrombolytic activities. The novel compounds 3f, 3i showed highest 69.7, 33.6% haemolysis of blood cells, respectively. The antithrombolytic activity of the compounds was found to be within low to moderate against human blood clot. The compound 3i showed potent clot lysis (31.5%).

Conclusions

Considering these results, it is concluded that the synthesized compounds can be used as a promising source of therapeutic agents.

Background

In present days, the synthesis of new and safe therapeutic agents is getting high importance in the field of medicinal science and pharmaceuticals. Most precisely, sulphur containing heterocycles are seen as the center of activity due to their widespread use in several important medicinal compounds. However, it is seen that the success of thiophene as an important moiety of medicinal agents led to the introduction of new therapeutic drugs. Substituted thiophene derivatives are well known for their chemotherapeutic applications. Many thiophene based heterocyclic compounds have shown versatile pharmacological activities such as antimicrobial [1],[2], antiamoebic [3], antiparasitic, anticancer [4], antifolates, antipsychotic [5], diabetes mellitus [6], anticonvulsant [7], analgesic [8], antidepressant [9], antihistaminic, anticholinergic [10], antiallergic [11]. In addition, the cholesterol inhibition activity and as antagonist against many hormones releasing receptors has also been reported. In a yet different context, the thiophene based heterocyclic compounds has also been employed in formulizing computer printer’s ink and as a raw material for herbicides and pesticides [12]. Some of the recent studies showed that the thiophene containing compounds constitutes an important class of materials, which show intrinsic electronic properties such as luminescence, redox activity, non-linear optical chromism and electron transport [13]-[17]. The incidence of death due to thrombosis is higher in the world. Antithrombolytic activity of thiophene based compounds has been reported in literature [18],[19].

In the synthesis of several types of organic compounds, the transition metal-catalyzed reactions are well known for the formation of new carbon–carbon (C–C) bonds. In this context, the Pd-catalyzed Suzuki–Miyaura coupling reaction [20] is one of the most efficient and unique method for the C–C bonds formation due to the requirement of mild reaction conditions, easily available environmentally safe organoboron compounds, high tolerance of functional groups and easy handling of the by-products [21]-[25].

The Suzuki–Miyaura cross-coupling reaction, which produces biaryls has proven to be the most important building blocks in organic synthesis owing to their industrial applications. We have previously reported the synthesis of arylthiophenes by regioselective Suzuki cross-coupling reactions and they were potentially studied as pharmaceutical agents [26],[27].

There are few reports about the Suzuki Cross Coupling reaction of benzyl halides with different palladium catalysts under variable reaction conditions. Langle et al. [28] reported the Suzuki cross coupling reaction of unsymmetrical diarylmethanes, while Bandgar et al. [29] reported ligand free Suzuki cross coupling reactions of benzylic halides with aryl boronic acid. Molander and Elia [30] described the Suzuki-Miyaura cross-coupling Reactions of Benzyl halides with Potassium Aryltrifluoroborates. The cross-coupling of benzylic bromides with various aryl boronic acids have also been reported under microwave conditions [31].

For the first time, the present work focuses on the synthesis of various palladium (0) catalyzed Suzuki cross coupled derivatives of 2-bromo-5-(bromomethyl)thiophene, particularly with the aim to investigate their biological activities (Haemolytic and Antithrombolytic activities).

Results and discussion

Chemistry

We have investigated the Suzuki cross coupling reactions of 2-bromo-5-(bromomethyl)thiophene (2) with various aryl boronic acids under optimized conditions. To the best of our knowledge, no such work on the synthesis and biological activities of 2-(bromomethyl)-5-aryl-thiophenes (3a–i) has been reported to date.

As outlined in the reaction scheme (1), the first step in the synthesis of 2-(bromomethyl)-5-aryl-thiophenes (3a–i) is the preparation of intermediate compound 2-bromo-5-(bromomethyl)thiophene (2), which was obtained in 58% yield from the reaction between 2-methylthiophene (1) and N-bromosuccinamide in CCl4 [32] (Scheme 1).

Scheme 1
scheme 1

Synthesis of intermediate compound 2-bromo-5-(bromomethyl)thiophene (2) and 2-(bromomethyl)-5-aryl-thiophenes 3a–i. Conditions: i, 1, (1 eq, 20.4 mmol), NBS (2.1 eq, 42.84 mmol), CCl4 (9–10 mL). Procedure: reflux 1 and NBS in CCl4 for 4–5 hours; Condition ii, 2 (1 eq, 0.976 mmol), Pd(PPh3)4 (2.5 mol%) aryl boronic acid (1.1 eq, 1.073 mmol), K3PO4 (2 eq, 1x.952 mmol), 1,4-dioxane/H2O (4:1) (Table 1), 12 h, 90°C.

In the next step, the Suzuki cross coupling reaction of appropriate aryl boronic acids with 2-bromo-5-(bromomethyl)thiophene (2) was carried out that eventually led to the corresponding 2-(bromomethyl)-5-aryl-thiophenes (3a-i) in moderate to excellent yields (25 − 76%) (Scheme 1, Table 1).

Table 1 Synthesis of 2-(bromomethyl)-5-aryl-thiophenes (3a-i)

The Suzuki-Miyaura cross coupling reaction of benzyl halide with aryl boronic acid usually follow slow oxidative addition and facile reductive elimination as compared to aryl halide [33],[34], therefore the reaction of aryl halide with aryl boronic acid is preferred over benzyl halide. The structures of these newly synthesized compounds were investigated from the data based on elemental analyses, Mass spectrometry, 1H-NMR and 13C-NMR spectra.

The results revealed that the compound 2-(bromomethyl)-5-(4 methoxyphenyl)thiophene (3b) was obtained in excellent yield (76%), which could be due to the solvent mixture (1,4-dioxane/water = 4:1), which has previously been reported to obtain high yields [35]. Another possible explanation is the high solubility of oxygen containing boronic acids in 1,4-dioxane, which led to the obtained high yield of compound (3b). The coupling of intermediate compound (2) with 3-chloro-4-fluoro phenyl boronic acid also gave 2-(bromomethyl)-5-(3-chloro-4-fluorophenyl)thiophene (3a) in good yield. The products 2-(bromomethyl)-5-(4-chlorophenyl)thiophene (3c), 2-(bromomethyl)-5-(3,5-difluorophenyl)thiophene (3d), 1-(3-(5-(bromomethyl)thiophene-2-yl)phenyl)ethanone (3e), 2-(bromomethyl)-5-(3,5-dimethylphenyl)thiophene (3i) were also obtained in relatively high yields ~ 63, 61, 63, 70% respectively. The obtained yield of products 2-(bromomethyl)-5-(4(methylthio)phenyl)thiophene (3f), 2-(bromomethyl)-5-(4-iodophenyl)thiophene (3g), 2-(bromomethyl)-5-p-tolylthiophene (3h) was fair as well (Table 1). In the cases, where low yield of products were obtained, the steric effects of substituents attached on aryl group of boronic acids and some practical problems associated with difficult chromatographic purification are suggested to be the possible issues [36]. Ortho-substituted aryl boronic acids have lack of reactivity and cannot couple in a good way due to steric factor. Hence, boronate anion of boronic acid are unable to attack easily on the substrate [36].

Biology

Measurement of potential cytotoxicity by haemolytic activity

The cytotoxicity of the synthesized compounds viz. 2 and 3a-i was studied by examining the haemolytic activity against human red blood cells. The cytotoxicity of blood lymphocytes, thymocytes and spleen cells of various compounds are already known [37]. When compared with the positive control triton X-100 standard, the novel compounds 3f and 3i showed significantly high haemolytic activity ~ 69.7 and 33.6% lysis of blood cells respectively, which can be attributed to the presence of electron donating methyl groups. Molongi et al. [38] reported that the anticancer activity is often enhanced by the presence of electron releasing groups. In contrast, the compounds viz. 2, 3a, 3b, 3c, 3d, 3e, 3g and 3h exhibited haemolytic activity below 10% (Table 2, Figure 1). In view of the observed differences in the % lysis of RBC values, it is inferred that the electron withdrawing and electron donating nature of the substituent groups have an influence on the haemolytic activity of the compounds [39]. Moreover, the cytotoxicity of the compounds viz. 3f and 3i can be optimized by making appropriate changes in the molecular structures for the purpose of their use as toxic compounds to control the uncontrolled proliferation of cells [38].

Table 2 Cytotoxicity studies by Haemolytic activity of synthetic compounds 2 and 3a-i
Figure 1
figure 1

Percentage of haemolysis of synthetic compounds 2, 3a-i.

Antithrombolytic activity

In the field of antithrombotic research, the compounds that exhibit anti-aggregatory activity have received a great deal of interest from research community. Several types of drugs such as heparin, ticlopidine, clopidogrel, plasminogen activator (t-PA), urokinase and streptokinase were explored as clot lysis agent but only few of them were found potent for clinical purposes [40]-[43].

Because of high death rate due to cardio-vascular diseases, the clot lysis activity is very important characteristic of any drug [44],[45]. The compounds under investigation exhibited low to moderate antithrombolytic activity against clot development in human blood. The compound 3i showed potent clot lysis (~ 31.5%), whereas, the compounds 3e and 2 showed comparatively low thrombolytic activity (Table 3, Figure 2). The values of % clot lysis for other compounds were found moderate. However, the results were significant p < 0.05, when compared with streptokinase taken as control. According to the best of our knowledge, no relative literature is available on this type of activity for such compound.

Table 3 Percentage efficiency of Clot lysis of synthetic compounds 2 and 3a-i
Figure 2
figure 2

Antithrombolytic activity of synthetic compounds 2, 3a-i.

Experimental

General

The melting points of compounds were determined using a Buchi melting point apparatus (B-540). High pure analytical grade reagents were used throughout all experiments and were purchased from Sigma Aldrich Chemical Co. (St. Louis, MO, USA) and Alfa Aesar Chemical Co. (St. Parkridge Ward Hill, MA, USA). 1H-NMR and 13C-NMR spectra were measured in CDCl3 and CD3OD (Bruker Aspect AM-300 instrument) at 300/75 MHz respectively. The chemical shift values (δ) were given in ppm and coupling constant was measured in Hertz (Hz). EI-MS spectra were recorded on a JMS-HX-110 spectrometer with a data system. Elemental analysis was carried out by using CHNS/O analyzer (Perkin-Elmer 2400 series). For column chromatography, silica gel (70–230 mesh) and silica gel (230–400 mesh) were used. The reactions were monitored on TLC, using Merck silica gel 60 PF254 cards. The compounds were visualized by UV lamp (254–365 nm).

General procedure for synthesis of 2-bromo-5-(bromomethyl)thiophene (2)

To carry out bromination of 2-methylthiophene, a weighed amount of starting material 2-methylthiophene (1, 1 eq, 20.4 mmol) suspended in 9–10 mL of dry carbon tetrachloride (CCl4) was made to react with N-bromosuccinimide (NBS) (2.1 eq, 42.84 mmol). This reaction mixture is then heated under reflux for four to five hours, followed by filtration and the removal of carbon tetrachloride under vacuum. Later on, the synthesized compound was purified by fractional distillation. Finally, the spectroscopic techniques were used to characterized the purified final product [32].

General procedure for the preparation of 2-(bromomethyl)-5-aryl-thiophene (3a-i)

Pd(PPh3)4 (2.5 mol%) was added to 2-bromo-5-(bromomethyl)thiophene (2, 1 eq, 0.976 mmol) under nitrogen atmosphere and the resulting mixture was stirred for 30 min with the addition of 1,4-dioxane (2.5 mL). After 30 min the aryl boronic acid (1.1 eq, 1.073 mmol), K3PO4 (2 eq, 1.952 mmol) and water (0.625 mL) were added [27]. The whole mixture was stirred for 12 h at 90°C, and was later removed and cooled to room temperature. After cooling to ambient temperature, the mixture was diluted with ethyl acetate and the organic layer was separated, dried with magnesium sulfate and the solvent was removed under vacuum. The obtained crude residue was purified by column chromatography using ethyl-acetate and n-hexane in (1:1) ratio to get the desired products, which were further analyzed by using different spectroscopic techniques.

Characterization data

2-bromo-5-(bromomethyl)thiophene (2). Brown liquid; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 6.98 (d, J = 3.6 Hz, 1H), 6.83 (d, J = 3.6 Hz, 1H), 4.68 (s, 2H-CH2). 13C-NMR (75 MHz CDCl3 + CD3OD): δ = 25.4, 108.2 128.0, 128.8, 141.5; EI/MS m/z (%:) 255.0 [M+˙]; 257.0 [M+ (Br79, Br81) 100], 259.0 [M+ (Br81, Br81) 40], [M+-Br] = 177.0; [M+-CH2Br] = 163.0; [M+-2Br] = 125.8; [M+-Br and CH2Br fragment] = 84.0. Anal. Calcd. for C5H4Br2S: C, 23.46; H, 23.50. Found: C, 1.60; H, 1.60%.

2-(bromomethyl)-5-(3-chloro-4-fluorophenyl)thiophene (3a). Light yellow solid, Mp: 200-250°C; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.54 (m, 1H-aryl), 7.52 (m, 1H-aryl), 7.36 (s, 1H-thiophene), 7.28 (m, 1H-aryl), 6.77 (s, 1H-thiophene), 4.07 (s, 2H-CH2). 13C-NMR (75 MHz CDCl3 + CD3OD): 27.4, 116.4, 121.2, 127.0, 127.6, 127.9, 129.0, 131.2, 137.0, 139.4, 158.0; EI/MS m/z (%): 304.8 [M+˙]; 306.8 [M+ (Br81,Cl35) 49]; 306.8 [M+ (Br79, Cl37) 17]; 308.8 [M+ (Br81, Cl37) 49]; [M+-F] = 287.2; [M+-Cl, F-fragments] = 253.1; [M+-CH2Br, thiophene, Cl- fragments] = 96.1. Anal. Calcd. For C11H7BrClFS: C, 43.23; H, 2.31. Found: C, 42.22; H, 2.40%.

2-(bromomethyl)-5-(4-methoxyphenyl)thiophene (3b). light yellow solid,Mp: 200-250°C; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.12 (d, J = 8.4 Hz, 1H-thiophene), 6.84-6.81 (m, 4H-aryl), 6.52 (d, J = 3.6 Hz, 1H-thiophene), 3.98 (s, 2H-CH2), 2.03 (s, 3H-OMe). 13C-NMR (75 MHz CDCl3 + CD3OD): 20.4, 27.9, 125.4, 125.9, 127.7, 127.9, 129.0, 129.9, 130.0, 131.9, 135.0, 139.1; EI/MS m/z (%): 283.0 [M+˙]; 285.0 [M+ (Br81) 49]; [M+-CH2Br, thiophene] = 108.2; [M+-CH2Br, thiophene, OMe- fragments] = 78.0. Anal. Calcd. For C12H11BrOS: C, 50.90; H, 3.92. Found: C, 50.76; H, 3.80%.

2-(bromomethyl)-5-(4-chlorophenyl)thiophene (3c). Yellow liquid; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.59 (d, J = 8.4 Hz, 2H-aryl), 7.40-7.37 (m, 2H-aryl, 1H-thiophene), 7.27 (s, 1H-thiophene), 4.70 (s, 2H-CH2). 13C-NMR (75 MHz CDCl3 + CD3OD): 27.6, 127.5 (2C), 128.5, 129.5 (2C), 128.4, 131.6, 134.1, 136.7, 139.1; EI/MS (m/z -ion mode): 286.9 [M+˙]; 288.9 [M+ (Br81,Cl35) 49]; 288.9 [M+ (Br79, Cl37)17]; 290.9 [M+ (Br81, Cl37) 49]; [M+-Br] = 223.0; [M+-CH2Br] = 194.2; [M+-CH2Br, Cl fragments] = 160.1, [M+-CH2Br, Cl, aryl fragments] = 83.2. Anal. Calcd. For C11H8BrClS: C, 45.94; H, 2.80. Found: C, 45.90; H, 2.70%.

2-(bromomethyl)-5-(3,5-difluorophenyl)thiophene (3d). Dark brown gummy matter; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.42 (m, 1H-aryl), 7.22 (m, 1H-aryl), 7.12 (d, J = 2.4 Hz, 1H-thiophene) 6.55 (m, 1H-aryl), 6.51 (d, J = 3.6 Hz, 1H-thiophene), 4.51 (s, 2H-CH2). 13C-NMR (75 MHz CDCl3 + CD3OD): 27.5, 104.0, 111.1 (2C), 127.5 (2C), 136.1, 136.9, 140.0, 165.1 (2C). EI/MS m/z (%): 288.0 [M+˙]; 290.0 [M+ (Br81) 49]; [M-F] = 270.0; [M-2 F] = 254.2; [M-CH2Br] = 196.0; [M-CH2Br, thiophene fragments] = 113.1. Anal. Calcd. For C11H7BrF2S: C, 45.69; H, 2.44. Found: C, 45.75; H, 2.43%.

1-(3-(5-(bromomethyl)thiophene-2-yl)phenyl)ethanone (3e). Off white gummy matter; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.87-7.85 (m, 2H-aryl), 7.50-7.41 (m, 2H-aryl), 6.91 (d, J = 3.6 Hz, 1H-thiophene), 6.66 (d, J = 3.6 Hz, 1H-thiophene), 4.83 (s, 2H-CH2), 2.57 (S, 3H-COMe). 13C-NMR (75 MHz CDCl3 + CD3OD): 26.5, 27.8, 126.0, 127.5 (2C), 128.5, 129.5, 130.5, 133.4, 136.0, 137.1, 139.0, 197.4. EI/MS m/z (%): 294.1 [M+˙]; 296.0 [M+ (Br81) 49]; [M+-Me] = 281.0 [M+-COMe] = 253.0, [M+-CH2Br] = 201.1, [M+-CH2Br, aryl, COMe] = 84.0. Anal. Calcd. For C13H11BrOS: C, 52.89; H, 3.76. Found: C, 52.80; H, 3.66%.

2-(bromomethyl)-5-(4-(methylthio)phenyl)thiophene (3f).off white solid,Mp: 110-150°C; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.10 (m, 4H-aryl), 7.01 (d, J = 3.9, 1H-thiophene), 6.89 (d, J = 3.6, 1H-thiophene), 4.84 (s, 2H-CH2). 13C-NMR (75 MHz CDCl3 + CD3OD): 14.6, 27.8, 127.3 (2C), 127.5 (2C)127. 9 (2C), 130.0, 135.9, 139.4, 140.2. EI/MS m/z (%): 299.0 [M+˙]; 301.0 [M+ (Br81) 49]; [M+-Me] = 284.0; [M+-SMe] = 251.0; [M+-Br, Me fragments] = 219.0; [M+-CH2Br, thiophene fragments] = 109.1; [M+-CH2Br, thiophene, SMe fragments] = 77.5. Anal. Calcd. For C12H11BrS2: C, 48.16; H, 3.71. Found: C, 48.10; H, 3.77%.

2-(bromomethyl)-5-(4-iodophenyl)thiophene (3g). Brown solid, Mp: > 300°C; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.76 (d, J = 2.1 Hz, 2H-Aryl), 7.58 (d, J = 1.8 Hz, 2H-aryl), 7.18 (d, J = 4.2 Hz, 1H-Thiophene), 6.82 (d, J = 3.3 Hz, 1H-Thiophene), 4.62 (s, 2H-CH2). 13C-NMR (75 MHz CDCl3 + CD3OD): 27.5, 94.6, 127.5 (2C), 129.0 (2C), 132.0, 135.7, 138.1 (2C), 140.0. EI/MS m/z (%): 378.1 [M+˙]; 380.0 [M+ (Br81) 49]; [M+-I] = 252.9; [M+-aryl, I] = 177.0; [M+-thiophene, aryl, I] = 95.8. Anal. Calcd. For C11H8BrIS: C, 34.85; H, 2.13. Found: C, 34.80; H, 2.11%.

2-(bromomethyl)-5-p-tolylthiophene (3h). Brown gummy matter;1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.55-7.40 (m, 4H-aryl, 2H-thiophene), 4.68 (s, 2H), 2.35 (S, 3H-Me). 13C-NMR (75 MHz CDCl3 + CD3OD): 21.0, 28.1, 125.5 (2C), 127.5 (2C), 129.6 (2C), 130.5, 131.8, 136.5, 139.6. EI/MS m/z (%): 266.9 [M+˙]; 268.9 [M+ (Br81) 49]; [M+-CH2Br] = 175.0; [M+-CH2Br, Me fragments] = 161.0; [M+-CH2Br, thiophene fragments] = 91.0; [M+-CH2Br, aryl, Me fragments] = 83.4. Anal. Calcd. For C12H11BrS: C, 35.94; H, 4.15. Found: C, 35.84; H, 4.25%.

2-(bromomethyl)-5-(3,5-dimethylphenyl)thiophene (3i).Brown liquid; 1H-NMR (300 MHz, CDCl3 + CD3OD): δ = 7.24 (s, 1H-aryl), 7.14 (d, J = 9.9, 2H-aryl), 7.11 (d, J = 10.5 Hz, 1H-thiophene), 6.95 (s, 1H-thiophene), 4.97 (s, 2H-CH2); 2.35 (s, 6H-2Me). 13C-NMR (75 MHz CDCl3 + CD3OD): 21.8 (2C), 27.6, 127.4 (3C), 127.8, 130.8, 133.6, 135.9, 138.6 (2C), 139.8. EI/MS m/z (%): 280.2 [M+˙]; 282.2 [M+ (Br81) 49]; [M+-2Me] = 252.0; [M+-CH2Br] = 189.0; [M+-CH2Br, aryl, 2Me] = 83.2; [M+-CH2Br, Me]ˉ = 174.0. Anal. Calcd. For C13H13BrS: C, 55.52; H, 4.66. Found: C, 55.58; H, 4.63%.

Cytotoxicity studies by haemolytic assay

The cytotoxicity of synthesized compounds 2 and 3a-i was determined by examining the haemolytic activity of human blood cells, following the previously reported method [46]. In a typical experiment, approximately 3 mL freshly obtained heparinized human blood was collected from the volunteers after consent and counseling. The blood samples were then centrifuged for 5 min at 1000 rpm, and the blood plasma was discarded and cells were washed three times with 5 mL chilled (4°C) sterile isotonic Phosphate-buffered saline (PBS) (pH 7.4). Erythrocytes were maintained 108 cells per mL for each assay. Approximately, 100 μL of each synthesized compound was mixed with human blood cells (108 cells/mL) separately. Later on, the Samples were incubated for 35 min at 37°C and agitated after 10 min. Soon after incubation, the samples were placed on ice for 5 min, followed by centrifuge for 5 min at 100 rpm. Supernatant 100 μL were taken from each tube and diluted 10 times with chilled (4°C) PBS. Triton X-100 (0.1% v/v) was taken as positive control and phosphate buffer saline (PBS) was taken as negative control and pass through the same process. The absorbance value was measured at 576 nm using μQuant (Bioteck, USA). Finally, the % RBCs lysis for each sample was calculated.

Antithrombolytic activity

The blood samples were collected from volunteers after consent and counseling. Venous blood was pinched from healthy human volunteers without a history of anticoagulant treatment. The 100 μL of blood was transmitted to each of the previously weighed micro-centrifuge tubes to form clots. Then the solution of synthesized compounds 2 and 3a-i (100 μL) having concentration of 1 mg/mL was added to the tubes, and incubated at 37°C for 45 minutes. Streptokinase was used as standard clot lysis agent and water as negative control for this assay. Clot lysis activity results were presented in percentage [47].

Conclusions

In conclusion, novel series of 2-(bromomethyl)-5-aryl-thiophenes(3a–i) were synthesized, and the cytotoxicity of the newly synthesized compounds (2, 3a-i) against the human blood cells was investigated. Almost, all the tested compounds revealed some haemolytic activity in the safe range but in particular 3f and 3i exhibited highest lysis of blood cells viz. 69.7 and 33.6 % respectively. The synthesized compounds exhibited low to moderate antithrombolytic activity against human blood clot. The compound 3i was found more potent for clot lysis among all synthesized compounds. We anticipate that the continued investigation in this field will provide new insights and promote the progress towards the development of ideal thrombolytic therapy, characterized by maximized stable coronary arterial thrombolysis with minimal bleeding. The highly toxic compounds are deemed to be potential antitumor agents.

References

  1. Chaudhary A, Jha K, Kumar S: Biological Diversity of Thiophene: A Review. J Adv Sci Res. 2012, 3 (3): 3-10.

    CAS  Google Scholar 

  2. Mohan C, Bhargava G, Bedi PM: Thieno [3, 2-d] pyrimidin-4-one Derivatives as Potential Antibacterial Agents. J Life Sci. 2009, 1 (2): 97-101.

    Google Scholar 

  3. Sharma S, Athar F, Maurya MR, Azam A: Copper (II) complexes with substituted thiosemicarbazones of thiophene-2-carboxaldehyde: synthesis, characterization and antiamoebic activity against E. histolytica. Eur J Med Chem. 2005, 40 (12): 1414-1419. 10.1016/j.ejmech.2005.05.013.

    Article  CAS  Google Scholar 

  4. Folkes AJ, Ahmadi K, Alderton WK, Alix S, Baker SJ, Box G, Chuckowree IS, Clarke PA, Depledge P, Eccles SA, Friedman LS, Hayes A, Hancox TC, Kugendradas A, Lensun L, Moore P, Olivero AG, Pang J, Patel S, Pergl-Wilson GH, Raynaud FI, Robson A, Saghir N, Salphati L, Sohal S, Ultsch MH, Valenti M, Wallweber HJ, Wan NC, Wiesmann C, et al: The identification of 2-(1H-indazol-4-yl)-6-(4-methanesulfonyl-piperazin-1-ylmethyl)-4-morpholin-4-yl-t hieno[3,2-d]pyrimidine (GDC-0941) as a potent, selective, orally bioavailable inhibitor of class I PI3 kinase for the treatment of cancer. J Med Chem. 2008, 51 (18): 5522-5532. 10.1021/jm800295d.

    Article  CAS  Google Scholar 

  5. Sharma C, Yerande S, Chavan R, V Bhosale A: Synthesis of thienopyrimidines and their antipsychotic activity. J Chem. 2010, 7 (2): 655-664.

    CAS  Google Scholar 

  6. Abdelhamid AO: Convenient Synthesis of Some New Pyrazolo (1, 5-a pyrimidine, Pyridine, Thieno (2, 3-b pyridine, and Isoxazolo (3, 4-d pyridazine Derivatives Containing Benzofuran Moiety. J Heterocycl Chem. 2009, 46 (4): 680-686. 10.1002/jhet.141.

    Article  CAS  Google Scholar 

  7. Laddha SS, Bhatnagar SP: A new therapeutic approach in Parkinson’s disease: Some novel quinazoline derivatives as dual selective phosphodiesterase 1 inhibitors and anti-inflammatory agents. Bioorg Med Chem. 2009, 17 (19): 6796-6802. 10.1016/j.bmc.2009.08.041.

    Article  CAS  Google Scholar 

  8. Alagarsamy V, Raja Solomon V, Meenac R, Ramaseshu K, Thirumurugan K, Murugesan S: Design and Synthesis of 2-Methylthio-3-substituted-5, 6-dimethylthieno [2, 3-d] pyrimidin-4 (3H)-ones as Analgesic, Anti-Inflammatory and Antibacterial Agents. Med Chem. 2007, 3 (1): 67-73. 10.2174/157340607779317599.

    Article  CAS  Google Scholar 

  9. Wardakhan W, Abdel-Salam O, Elmegeed G: Screening for antidepressant, sedative and analgesic activities of novel fused thiophene derivatives. Acta Pharm. 2008, 58 (1): 1-14. 10.2478/v10007-007-0041-5.

    Article  CAS  Google Scholar 

  10. Shireesha B, UmaShankar K, RaghuramRao A, Rajan K, Raghuprasad M: Design, Synthesis and H1-Antihistaminic Activity of Novel Thieno [2, 3-d] pyrimidinones. Int J Pharm Sci Nanotechnol. 2008, 1 (2): 136-143.

    CAS  Google Scholar 

  11. Connor DT, Sorenson RJ, Cetenko WA, Kerbleski JJ, Tinney FJ: Synthesis and antiallergy activity of 10-oxo-10H-pyrido [1, 2-a] thieno [3, 2-d] pyrimidines and 10-oxo-10H-pyrido [1, 2-a] thieno [3, 4-d] pyrimidines. J Med Chem. 1984, 27 (4): 528-530. 10.1021/jm00370a016.

    Article  CAS  Google Scholar 

  12. Russel K, Press B, Rampulla A: Thiophene system 9, Thienopyrimidinedione derivatives as potential antihypertensive agent. J Med Chem. 1988, 31: 1786-1789. 10.1021/jm00117a019.

    Article  Google Scholar 

  13. Garnier F, Yassar A, Hajlaoui R, Horowitz G, Deloffre F, Servet B, Ries S, Alnot P: Molecular engineering of organic semiconductors: design of self-assembly properties in conjugated thiophene oligomers. J Am Chem Soc. 1993, 115 (19): 8716-8721. 10.1021/ja00072a026.

    Article  CAS  Google Scholar 

  14. Garnier F, Hajlaoui R, Yassar A, Srivastava P: All-Polymer Field-Effect Transistor Realized by Printing Techniques. Science. 1994, 265 (5179): 1684-1686. 10.1126/science.265.5179.1684.

    Article  CAS  Google Scholar 

  15. Garnier F: Functionalized Conducting Polymers—Towards Intelligent Materials. Angewandte Chemie. 1989, 101 (4): 529-533. 10.1002/ange.19891010447.

    Article  CAS  Google Scholar 

  16. Dodabalapur A, Torsi L, Katz H: Organic transistors: two-dimensional transport and improved electrical characteristics. Science. 1995, 268 (5208): 270-271. 10.1126/science.268.5208.270.

    Article  CAS  Google Scholar 

  17. Dodabalapur A, Katz HE, Torsi L: Molecular orbital energy level engineering in organic transistors. Adv Mater. 1996, 8 (10): 853-855. 10.1002/adma.19960081021.

    Article  CAS  Google Scholar 

  18. Roehrig S, Straub A, Pohlmann J, Lampe T, Pernerstorfer J, Schlemmer KH, Reinemer P, Perzborn E: Discovery of the novel antithrombotic agent 5-chloro-N-({(5S)-2-oxo-3- [4-(3-oxomorpholin-4-yl)phenyl]-1,3-oxazolidin-5-yl}methyl)thiophene- 2-carboxamide (BAY 59–7939): an oral, direct factor Xa inhibitor. J Med Chem. 2005, 48 (19): 5900-5908. 10.1021/jm050101d.

    Article  CAS  Google Scholar 

  19. Dupin J, Gryglewski R, Gravier D, Hou G, Casadebaig F, Swies J, Chlopicki S: SYNTHESIS AND THROMBOLYTIC ACTIVITY. J Physiol Pharmacol. 2002, 53 (4): 625-634.

    CAS  Google Scholar 

  20. Miyaura N, Yanagi T, Suzuki A: The palladium-catalyzed cross-coupling reaction of phenylboronic acid with haloarenes in the presence of bases. Synthetic Comm. 1981, 11 (7): 513-519. 10.1080/00397918108063618.

    Article  CAS  Google Scholar 

  21. Martin AR, Yang Y: Palladium-catalyzed cross-coupling reactions of organoboronic acids with organic electrophiles. Acta Chem Scand. 1993, 47: 221-230. 10.3891/acta.chem.scand.47-0221.

    Article  CAS  Google Scholar 

  22. Suzuki A: New synthetic transformations via organoboron compounds. Pure Appl Chem. 1994, 66 (2): 213-222. 10.1351/pac199466020213.

    Article  CAS  Google Scholar 

  23. Stanforth SP: Catalytic cross-coupling reactions in biaryl synthesis. Tetrahedron. 1998, 54 (3–4): 263-303. 10.1016/S0040-4020(97)10233-2.

    Article  CAS  Google Scholar 

  24. Suzuki A: Recent advances in the cross-coupling reactions of organoboron derivatives with organic electrophiles, 1995–1998. J Organomet Chem. 1999, 576 (1–2): 147-168. 10.1016/S0022-328X(98)01055-9.

    Article  CAS  Google Scholar 

  25. Miyaura N, Suzuki A: Palladium-catalyzed cross-coupling reactions of organoboron compounds. Chem Rev. 1995, 95 (7): 2457-2483. 10.1021/cr00039a007.

    Article  CAS  Google Scholar 

  26. Ali S, Rasool N, Ullah A, Nasim F-u-H, Yaqoob A, Zubair M, Rashid U, Riaz M: Design and Synthesis of Arylthiophene-2-Carbaldehydes via Suzuki-Miyaura Reactions and Their Biological Evaluation. Molecules. 2013, 18 (12): 14711-14725. 10.3390/molecules181214711.

    Article  CAS  Google Scholar 

  27. Dang TT, Rasool N, Dang TT, Reinke H, Langer P: Synthesis of tetraarylthiophenes by regioselective Suzuki cross-coupling reactions of tetrabromothiophene. Tetrahedron Lett. 2007, 48 (5): 845-847. 10.1016/j.tetlet.2006.11.152.

    Article  CAS  Google Scholar 

  28. Langle S, Abarbri M, Duchêne A: Selective double Suzuki cross-coupling reactions. Synthesis of unsymmetrical diaryl (or heteroaryl) methanes. Tetrahedron Lett. 2003, 44 (52): 9255-9258. 10.1016/j.tetlet.2003.10.080.

    Article  CAS  Google Scholar 

  29. Bandgar B, Bettigeri SV, Phopase J: Palladium catalyzed ligand-free Suzuki cross-coupling reactions of benzylic halides with aryl boronic acids under mild conditions. Tetrahedron Lett. 2004, 45 (37): 6959-6962. 10.1016/j.tetlet.2004.07.073.

    Article  CAS  Google Scholar 

  30. Molander GA, Elia MD: Suzuki-Miyaura cross-coupling reactions of benzyl halides with potassium aryltrifluoroborates. J Org Chem. 2006, 71 (24): 9198-9202. 10.1021/jo061699f.

    Article  CAS  Google Scholar 

  31. McDaniel SW, Keyari CM, Rider KC, Natale NR, Diaz P: Suzuki-Miyaura Cross-Coupling of Benzylic Bromides Under Microwave Conditions. Tetrahedron Lett. 2011, 52 (43): 5656-5658. 10.1016/j.tetlet.2011.08.096.

    Article  CAS  Google Scholar 

  32. Dittmer K, Martin RP, Herz W, Cristol SJ: The Effect of Benzoyl Peroxide on the Bromination of Methylthiophenes by N-Bromosuccinimide. J Am Chem Soc. 1949, 71 (4): 1201-1204. 10.1021/ja01172a016.

    Article  CAS  Google Scholar 

  33. Negishi E-i, de Meijere A, Wiley J: Handbook of organopalladium chemistry for organic synthesis. 2002, Wiley-Interscience, New York

    Book  Google Scholar 

  34. Juteau H, Gareau Y, Labelle M, Sturino CF, Sawyer N, Tremblay N, Lamontagne S, Carriere MC, Denis D, Metters KM: Structure-activity relationship of cinnamic acylsulfonamide analogues on the human EP3 prostanoid receptor. Bioorg Med Chem. 2001, 9 (8): 1977-1984. 10.1016/S0968-0896(01)00110-9.

    Article  CAS  Google Scholar 

  35. Smith GB, Dezeny GC, Hughes DL, King AO, Verhoeven TR: Mechanistic studies of the Suzuki cross-coupling reaction. J Org Chem. 1994, 59 (26): 8151-8156. 10.1021/jo00105a036.

    Article  CAS  Google Scholar 

  36. Tùng ĐT, Tuân ĐT, Rasool N, Villinger A, Reinke H, Fischer C, Langer P: Regioselective Palladium (0)‐Catalyzed Cross‐Coupling Reactions and Metal‐Halide Exchange Reactions of Tetrabromothiophene: Optimization, Scope and Limitations. Adv Synth Catal. 2009, 351 (10): 1595-1609. 10.1002/adsc.200900044.

    Article  Google Scholar 

  37. Mavrova A, Wesselinova D, Tsenov YA, Denkova P: Synthesis, cytotoxicity and effects of some 1,2,4-triazole and 1,3,4-thiadiazole derivatives on immunocompetent cells. Eur J Med Chem. 2009, 44 (1): 63-69. 10.1016/j.ejmech.2008.03.006.

    Article  CAS  Google Scholar 

  38. Mologni L, Rostagno R, Brussolo S, Knowles PP, Kjaer S, Murray-Rust J, Rosso E, Zambon A, Scapozza L, McDonald NQ: Synthesis, structure-activity relationship and crystallographic studies of 3-substituted indolin-2-one RET inhibitors. Bioorg Med Chem. 2010, 18 (4): 1482-1496. 10.1016/j.bmc.2010.01.011.

    Article  CAS  Google Scholar 

  39. Ding H, Chen Z, Zhang C, Xin T, Wang Y, Song H, Jiang Y, Chen Y, Xu Y, Tan C: Synthesis and Cytotoxic Activity of Some Novel N-Pyridinyl-2-(6-phenylimidazo[2,1-b]thiazol-3-yl)acetamide Derivatives. Molecules. 2012, 17 (4): 4703-4716. 10.3390/molecules17044703.

    Article  CAS  Google Scholar 

  40. Panak E, Maffrand J, Picard-Fraire C, Vallee E, Blanchard J, Roncucci R: Ticlopidine: a promise for the prevention and treatment of thrombosis and its complications. Haemostasis. 1983, 13 (Suppl 1): 1-54.

    Google Scholar 

  41. Coukell AJ, Markham A: Clopidogrel. Drugs. 1997, 54 (5): 745-750. 10.2165/00003495-199754050-00006. discussion 751

    Article  CAS  Google Scholar 

  42. Mucklow J: Thrombolytic treatment. Streptokinase is more economical than alteplase. BMJ. 1995, 311 (7018): 1506-10.1136/bmj.311.7018.1506.

    Article  CAS  Google Scholar 

  43. Collen D: Coronary thrombolysis: streptokinase or recombinant tissue-type plasminogen activator?. Ann Intern Med. 1990, 112 (7): 529-538. 10.7326/0003-4819-112-7-529.

    Article  CAS  Google Scholar 

  44. Hunt BJ: Awareness and politics of venous thromboembolism in the United kingdom. Arterioscler Thromb Vasc Biol. 2008, 28 (3): 398-399. 10.1161/ATVBAHA.108.162586.

    Article  CAS  Google Scholar 

  45. Allroggen H, Abbott RJ: Cerebral venous sinus thrombosis. Postgrad Med J. 2000, 76 (891): 12-15. 10.1136/pmj.76.891.12.

    Article  CAS  Google Scholar 

  46. Shahid M, Bukhari SA, Gul Y, Munir H, Anjum F, Zuber M, Jamil T, Zia KM: Graft polymerization of guar gum with acryl amide irradiated by microwaves for colonic drug delivery. Int J Biol Macromol. 2013, 62: 172-179. 10.1016/j.ijbiomac.2013.08.018.

    Article  CAS  Google Scholar 

  47. Prasad S, Kashyap RS, Deopujari JY, Purohit HJ, Taori GM, Daginawala HF: Development of an in vitro model to study clot lysis activity of thrombolytic drugs. Thromb J. 2006, 4 (14): 1-4.

    Google Scholar 

Download references

Acknowledgments

The present data is the part of Ph.D thesis research work of Komal Rizwan. Higher Education Commission (HEC) Pakistan is highly acknowledged for financial support (Scholarschip Pin # 2 ps1-388). The authors also gratefully acknowledge the financial support by HEC (HEC Project No. 20-1465/R&D/09/5458). The authors would also like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for funding through the Research Group Project No. RGP-VPP-345.

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to Muhammad Zubair, Nasir Rasool or Hawa ZE Jaafar.

Additional information

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

KR, MZ, NR, MZ, SA, AFZ, UAR, SUK and MS made a significant contribution to experiment design, acquisition of data, analysis and drafting of the manuscript. MZUH and HZEJ have made a substantial contribution to interpretation of data, drafting and carefully revising the manuscript for intellectual content. All authors read and approved the final manuscript.

Authors’ original submitted files for images

Below are the links to the authors’ original submitted files for images.

Authors’ original file for figure 1

Authors’ original file for figure 2

Rights and permissions

Open Access  This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rizwan, K., Zubair, M., Rasool, N. et al. Regioselective synthesis of 2-(bromomethyl)-5-aryl-thiophene derivatives viapalladium (0) catalyzed suzuki cross-coupling reactions: as antithrombotic and haemolytically active molecules. Chemistry Central Journal 8, 74 (2014). https://doi.org/10.1186/s13065-014-0074-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s13065-014-0074-z

Keywords