- Research article
- Open Access
An expeditious and environmentally benign synthesis of dispiro-3-phenylpyrrolothiazoles in ACI/EG eutectic mixture and its antioxidant and antimicrobial activities against urinary tract pathogens
BMC Chemistry volume 13, Article number: 42 (2019)
The present study reveals the robust and facile methodology for the synthesis of massively selective dispiro-3-phenylpyrrolothiazole hybrids via one-pot 1,3-dipolar cycloaddition reaction by environmentally supported solvents and to evaluate their biological activities. The quaternary ammonium salt eutectic mixture, acetylcholine iodide-ethylene glycol (ACI/EG) medium brings an efficient environment for the synthesis of dispiropyrrolothiazole with excellent yield in shorter reaction time than imidazolium ionic liquids. The eutectic mixture was recovered and reused without any significant drop in their catalytic activity. Among the eight synthesized compounds 4a–h, halogen derivatives are exhibiting significant antimicrobial activities against selected uropathogens pathogens. Interestingly, chloro and bromo derivatives exhibits the minimum inhibitory concentration (MIC) of 12.5 μg/ml and 6.25 μg/ml towards Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus respectively. In addition, the IC50 values of DPPH radicals with synthesized compounds are interesting, particularly compounds 4a, 4d and 4e shows lower than the control BHA indicating their potent scavenging ability of free radicals.
Adult women become frequent victims than men at a ratio of 8:1 for urinary tract infection (UTI) because of their anatomical differences. In general, Gram-positive and Gram-negative bacteria and certain fungi are the causative agents of UTI. Frequent infection is the most important factor contributing to high risk UTI which results in pyelonephritis with sepsis, renal damage, kidney damage, bladder inflammation and urethritis. By nature, urinary track is sterile but colonization of pathogens, particularly Uropathogenic Escherichia coli (UPEC) in the urinary tract will leads to highly complicated UTI . The pathogens viz. Staphylococcus saprophyticus, Enterococcus faecalis, Pseudomonas aeruginosa and Candida spp. may create non-complicating infections in the initial stage. Unfortunately, followed by UPEC infection, Enterococcus spp., Klebsiella pneumoniae, Candida spp., Staphylococcus aureus, P. aeruginosa, P. mirabilis, and group B Streptococcus (GBS) are the responsible pathogens for complicated UTI. UTI is more precarious at the time of pregnancy for both parental and infant health because it can affect kidney easily . Nosocomial infections [3, 4] and increasing resistance to antimicrobial agents  are the other unavoidable risk factors associated with UTI treatment. Though antibiotics can be used to treat UTI, long-term treatment creates antibiotic resistance which leads to negative side-effect of UTI treatment including exhaustion of beneficial gut and mucosal microorganism, hypersensitivity, and suppressing immune development in the body . Certainly, there is a need to develop a highly potent and efficient antimicrobial drug for the treatment of infectious diseases which is suitable to treat patients.
Heteroatom consisting cyclic hydrocarbons are fascinating molecules because of their treasured applications in medicinal field. Particularly, structurally rigid spiro heterocyclic analogues showed highly pronounced pharmacological properties and exist in many naturally occurring alkaloids . Having medicinal values, thiazolidine ring systems play an important role in organic synthesis particularly antimicrobial substances such as penicillins, cephalosporins, narcodicins, thienamicyn and other compounds that have physiological activities have been prepared from thiazolidine . It is noted that spiropyrrolothiazole analogues are interesting because of their wide range of biological activities such as anti-cancer , anti-diabetic , antibiotic , anti-inflammatory , hepatoprotective , anti-convulsant , anti-leukemic agents , Alzheimer disease , and also good in anti-mycobacterial . Spiro indolin-2-one nucleus was reported to treat diabetic patients, HIV-1 protease inhibitors, potent gastrain/CCK-B receptor antagonist and for growth hormone secretagogue receptor agonists . Also, indane-1,3-dione displays anti-blood coagulation, anti-inflammatory, anti-biotic and anti-convulsant activities . Synthesis and antimicrobial screening of a series of structurally complexed molecules with the above mentioned molecular units viz. indane-1,3-dione, indolin-2-one, and pyrrolothiazole ring with spiro junction will be a novel compound with efficient antimicrobial activities against UTI.
The design of present molecular framework stems from the promising UTI activity of thiazolidine units reported by Reese et al. . In addition, the supposition that the rigidity of spiro molecular frameworks would easily binds with the biomolecules, prompted us to synthesize spiropyrrolothiazolidine derivatives for UTI applications. In these contexts, multicomponent 1,3-dipolar cycloaddition reactions are highly suitable and powerful methodology for the construction of pharmacologically valuable heterocyclic compounds. Particularly the chemistry of azomethine ylide 1,3-dipolar cycloaddition reaction is an interesting, less time consuming, and significant for construction of heterocyclic compounds with high stereo and chemoselectivity [21, 22]. Considering framework of environmental green chemical approach, alternative medium for organic solvents occupying predominating place in the organic synthesis. The required reaction medium must have environmentally benign criteria such as non-toxicity, biodegradability, availability, recyclability and also in economically beneficial among others. However, interesting green protocols have been reported in the literature for the synthesis of heterocyclic compounds through multicomponent reaction including microwave assisted , solid support and montmorillonite clay catalyzed [24, 25], ultrasonic triggered , and with different class of eutectic mixture solvent mediated synthesis [27, 28]. Among the various green protocols, room temperature eutectic mixtures are perspective and effective method for chemical transformations.
Environmentally green quaternary ammonium salt eutectic mixture, Acetylcholine iodide-ethylene glycol (ACI/EG) mediated protocol is an efficient reaction medium for the synthesis of heterocyclic molecules through multicomponent reaction methodology has been reported by our research group recently . In continuous of our research program on the synthesis of spiro heterocyclic derivatives, for the first time, herein we wish to report that ACI/EG as an efficient eutectic mixture medium for the synthesis of biologically significant dispiro-3-phenylpyrrolothiazole analogues and their UTI activities.
Results and discussion
Cyclization of l-cysteine with benzaldehyde in water medium undergoes a smooth reaction yielding an analogue of proteinogenic amino acid, 2-phenyl-1,3-thiazolidine-4-carboxylic acid (1) at room temperature  which is used to generate in situ azomethine ylide with ninhydrin (2). The dipolarophile bearing indolin-2-one group was prepared by reacting oxindole with various p-substituted aromatic aldehyde through base catalyst condensation reaction. In the present investigation in a green protocol, the cyclic amino acid, 2-phenyl-1,3-thiazolidine-4-carboxylic acid (1) was reacted with triketone, ninhydrin (2) to generate in situ azomethine ylide, which undergoes one-pot 1,3-dipolar cycloaddition with various para-alkyl/halide substituted 3-arylideneoxindoles (3a–h), as dipolarophiles under optimized reaction conditions. In the initial stage, a pilot reaction was carried out with cyclic amino acid (1), ninhydrin (2), and 3-benzylideneindolin-2-one (3a) by using imidazolium eutectic mixtures viz., [Bmim][OH], [Bmim][Br], [Bmim][BF4], [Bmim][PF6], [Bmim][Cl], [Emim][ClO4], [Emim][CF3SO3], [Emim][PF6], [Emim][NO3] and also in quaternary ammonium salt eutectic mixture ACI/EG as solvent. Among the various solvent medium, our recent research [29, 31] heads-up us to utilize ACI/EG eutectic mixture as a green solvent reaction medium and it furnished dispiro-3-phenylpyrrolothiazole 4a in excellent yield of 89% in short reaction time at 50 °C. As eutectic mixture possesses similar physio-chemical properties as ionic liquids , the rationale for the formation of spirocycloadduct follows the same pathway as in ionic liquids [33, 34]. Optimization of the reactions in room temperature and 50 °C were compared and presented in Table 1. The required inexpensive quaternary ammonium salt eutectic mixture, ACI/EG was prepared in good yield by mixing acetylcholine iodide and ethylene glycol at a 1: 9 molar ratio and then the mixture was heated at 70 °C .
Having optimized reaction conditions, all the subsequent reactions were performed through decarboxylative azomethine ylide condensation of an equimolar mixture of the reactants 1, 2 and 3a–h in one-pot treated in ACI/EG eutectic mixture at 50 °C for 1 h (Scheme 1). After completion of the reaction (monitored by TLC), the crude product was washed with water and the pure novel dispiro-3-phenylpyrrolothiazoles (4a–h) was isolated through flash column chromatography by using EtOAc:hexane (2:8).
The structure and stereochemistry of all the cycloadducts were confirmed by their spectral data. In the IR spectrum of cycloadduct 4d, the carbonyl groups of indane-1,3-dione exhibited two absorption bands at 1740 cm−1 and 1703 cm−1 and the amide carbonyl carbon exhibited a band at 1695 cm−1. 1H NMR spectrum of compound 4d showed a doublet at δ 4.42 for Ha proton and a multiplet at δ 5.12–5.20 for Hb proton and their correlation was also evidenced by 1H-1H COSY spectrum. The benzylic proton of the thiazolidine ring resonated as a singlet at δ 5.31 and the corresponding carbon signal appeared at 73.6 ppm as evidenced from its 1H-13C COSY by the appearance of isolated contour plot. The two multiplets appeared at δ 3.10–3.16 and δ 3.66–3.73 were due to Hd protons. In hetero-COSY spectrum, the carbon corresponding to these Hd protons appeared at 38.2 ppm, which is further confirmed from DEPT-135 analysis. The Hb proton in tertiary carbon appeared as a multiplet between δ 5.12 and 5.20. The NH proton of the oxindole ring system resonated as a singlet at δ 8.90. In the 13C NMR spectrum of cycloadduct 4d, two spiro quaternary carbons appeared at 68.40 and 77.85 ppm. The oxindole carbonyl carbon resonated at 172.76 ppm and indanedione carbonyl carbons appeared at 193.44 and 200.20 ppm. For further clarification, 1D and 2D NMR spectra of compound 4d is provided in the Additional file 1. Finally, the mass spectrum of cycloadduct 4d exhibited the molecular ion peak at m/z 563.07 which confirmed the formation of cycloadduct and the compound gave satisfactory elemental analysis. All the spectral data agreed well with the deduced structure of the cycloadduct. The data in Table 2 show that the ability of formation of cycloadducts in the presence of either electron releasing or electron withdrawing groups at the dipolarophile. The pictorial representation of the chemical shift values for cycloadduct 4d is presented in Fig. 1.
The recovered wet eutectic mixture ACI/EG from the reaction mixture was completely purified by applying high vacuum at 60 °C. The catalytic activity of the purified eutectic mixture was further investigated and identified it efficiency for consecutive reaction. The results presented in Fig. 2, clearly show that the catalytic activity and efficiency of the reused eutectic mixture are good and effective for four consecutive runs.
In the biological studies, the antibacterial activity assessment of dispiropyrrolothiazole compounds 4a–h against the three Gram-negative and three Gram-positive uropathogens and two ATCC reference strains were studied using the agar well diffusion method. The data accompanying with the antibacterial prospective of the dispiropyrrolothiazole compounds are presented in Table S1 in the Additional file 1. The efficacy of antibacterial inhibitory activity diverges with respect to each compound against a panel of uropathogens. The zone of inhibition diameters was a maximum of 26.00 mm and a minimum of 9.00 mm whereas the standard antibiotic streptomycin had a higher zone of inhibition ranging from 15.00 to 30.00 mm (Fig. 3). The dispiropyrrolothiazole compounds exhibited antibacterial activity against almost all tested uropathogens except E. faecalis. The highest inhibition zone was observed on 4e against K. pneumoniae (24.00 mm) and E. coli (22.00 mm) followed by S. aureus (18.00 mm). The moderate inhibitory activity was displayed by 4d K. pneumoniae (15.00 mm) and E. coli (14.00 mm) followed by S. aureus (13.00 mm) and P. aeruginosa (10.00 mm) and 4a E. coli (12.50 mm), S. aureus (9.00 mm) and P. aeruginosa (10.5 mm)) was found to be less effective than compound 4d. On the other hand, other dispiro-3-phenylpyrrolothiazole derivatives such as 4b, 4c, 4f, 4g and 4h showed least efficacy (7.10 to 9.50 mm) against tested uropathogens. Among all tested synthetic dispiro-3-phenylpyrrolothiazole analogues, 4a, 4d and 4e were more efficient and the order of potential antibacterial activity is 4e > 4d > 4a.
The MIC test of dispiropyrrolothiazole derivatives against six uropathogens and two ATCC strains were carried out with the tube dilution technique. The MIC results are shown in Table 3. The half of tested uropathogens was showed resistant to compound 4a, later it was exempted from MIC study. The MIC values were range from 6.25 to 100.00 µg/ml. The most susceptible uropathogens were K. pneumoniae and E. coli (6.25 µg/ml), followed by S. aureus (12.50 µg/ml), whereas the other uropathogens MICs range from 25.00 to 100.00 µg/ml and it was deliberately less susceptible (Table 3).
Antioxidant activity by DPPH method
The free radical scavenging activity of dispiropyrrolothiazole compounds 4a–h was carried out in the presence of 1,1-diphenyl-2-picrylhydrazyl (DPPH- free radical) and using tert-butyl-4-hydroxyanisole (BHA) antioxidant agents as positive control. The DPPH method is highly reliable, rapid and also one of the most appropriate methods for determines the antioxidant activity. The inhibitory effects of different concentrations of synthesized dispiropyrrolothiazole compounds 4a–h on DPPH radical are depicted in Fig. 4. The antioxidant activity is expressed in terms of % inhibition and IC50 (effective concentration for scavenging 50% of the initial DPPH) value (μM).
Based on the results, among all the synthesized dispiropyrrololhiazoles compounds 4a–h showed scavenging activity towards DPPH. These compounds were shown an active inhibitory effect against DPPH radical at 250 μM concentration and inhibition rates were: 97.20% ± 1.05% (for 4d), 94.00% ± 1.25% (for 4a), and 92.30% ± 1.50% (for 4e) better than the positive control BHA (89.10% ± 1.30%). Whereas, the compounds 4b, 4c and 4 g were exposed less inhibitory activity than the BHA. These compounds 4a, d, e inhibited the DPPH activity with an IC50 = 35.30 μM (4a), 32.50 μM (4d) and 36.80 μM (4e) which is better than the specific inhibitor of BHA (IC50 = 58.60 μM).
Materials and methods
The uropathogens being used were Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Klebsiella pneumoniae (K. pneumoniae), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis) and Enterococcus faecalis (E. faecalis). In addition, Escherichia coli (E. coli ATCC 25922) and Staphylococcus aureus (S. aureus ATCC 29213), the two ATCC reference cultures, are also included. The bacterial cultures were obtained from BioLine Laboratory, Coimbatore, Tamil Nadu. The organisms were periodically sub-cultured and maintained in a nutrient agar slant at 4 °C.
The uropathogens were grown in a 5 ml brain heart infusion (BHI) broth at 37 °C antibacterial activity assessment. Eighteen hour old pure bacterial culture was used to prepare a density of 108 cells/ml of 0.5 McFarland standard at the time of each experiment. Muller-Hinton agar (MHA) was prepared according to the manufacturer’s instruction, autoclaved and dispensed in a sterile plate. All the culture media were purchased from HiMedia Pvt. Ltd., Mumbai, India.
Antibacterial susceptibility tests
Agar well diffusion
The UTI bacterial broth culture was prepared to a density of 108 cells/ml of 0.5 McFarland standards. The aliquot was spread evenly onto Muller Hinton Agar plates with a sterile cotton swab. Then, the plated medium was allowed to dry at room temperature for 30 min . On each plate, equidistant wells were made with a 6 mm diameter sterilized, cork borer, 2 mm from the edge of the plate. Fifty microliter of each dispiro-3-phenylpyrrolothiazole compounds (100 µg/ml) were aseptically introduced into an agar well. Streptomycin (15 µg/ml) were used as positive controls and the DMSO was included as negative controls. This was followed by allowing the agar plate on the bench for 20 min pre-diffusion followed by incubation at 37 °C for 24 h. The formation of a clear inhibition zone of ≥ 7 mm diameters around the wells was regarded as significant susceptibility of the organisms to the dispiro-3-phenylpyrrolothiazoles 4a–h. All the experiment was performed in triplicate.
Determination of minimum inhibitory concentration (MIC)
The tube dilution technique  was used to determine the MIC of dispiro-3-phenylpyrrolothiazole derivatives that shows a maximum zone of inhibition at agar well methods. The dispiro-3-phenylpyrrolothiazole derivatives 4d and 4e was used to determine the MIC by tube dilution technique which was showed maximum zone of inhibition at agar well method. Both compounds were serially diluted in the range from 3.125 to 100 µg/ml. The tubes were inoculated with 100 µl of UTI bacterial pathogens at a concentration of 106 cells/ml. Standard antibiotics streptomycin was included in the assay for comparison. Nutrient broth with the inoculum only was used as control. All the experiments were carried out in triplicate. The tubes were incubated aerobically at 37 °C for 18 h. The growths of inoculum were decreased in the next dilution was taken as MIC values.
Antioxidant activity by DPPH method
The antioxidant activity of all the synthesized compounds was evaluated by DPPH method with some modifications and compared with standard BHA. The 400 μM solution of DPPH (2 ml) in ethanol was added to tested sample solutions (2 ml) of different concentrations (75, 150, and 250 μM) in acetone–ethanol 4:96 v/v. The samples were kept in the dark at room temperature. After 30 min the absorbance values were measured at 517 nm and were converted into the percentage antioxidant activity (%) using the formula :
where, Acontrol was the absorbance of DPPH solution without sample, Asample was the absorbance of sample solution with DPPH, Asampleblank was the absorbance of the sample solutions without the DPPH.
All analyses were undertaken on three replicates and the results averaged. The IC50 values were calculated by linear regression plots, where the abscissa represented the concentration of tested compound solution (75, 150, and 250 μM) and the ordinate represented the average percent of antioxidant activity from three separate tests. The absorbance was measured on a spectrophotometer.
General procedure for the synthesis of dispiropyrrolothiazoles 4a–h
To a suspension of 2-phenylthiazolidine-4-carboxylic acid (1) (209 mg, 1.0 mmol) in ACI/EG (3.0 ml) were added ninhydrin (2) (160 mg, 1.0 mmol) and 3-arylidene isatin (3a–h) (1.0 mmol) at room temperature. The reaction mixture was stirred at 50 °C for 1 h. After completion of the reaction, tested by TLC, the crude product was washed with water and purified by flash column chromatography over silica gel with a hexane–ethyl acetate mixture (8:2) to give pure dispiropyrroloisoquinolines (4a–h) in good to excellent yield.
Spectral data of the synthesized cycloadducts
Hexahydro-3,7-diphenylspiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″] oxindolopyrrolo[1,2-c]thiazole, 4a.Yellow solid, mp 132–134 °C; IR (KBr) 3388, 1744, 1706, 1698 cm−1; 1H (300 MHz, CDCl3) δ 3.13–3.17 (m, 1H, Hd1); 3.65–3.71 (m, 1H, Hd2); 4.37 (d, 1H, Ha, J = 9.3 Hz); 5.16–5.23 (m, 1H, Hb); 5.24 (s, 1H, Hc); 6.42–8.14 (m, 18H, ArH); 9.89 (s, 1H, NH). 13C (75 MHz, CDCl3) 38.2, 55.4, 67.8, 71.5, 73.3, 78.3, 109.3, 120.9, 122.4, 122.6, 124.4, 126.5, 127.1, 127.2, 127.5, 127.6, 127.9, 128.1, 128.4, 133.2, 135.3, 135.9, 139.6, 140.6, 141.1, 172.4, 192.8, 199.8. EI-MS m/z 528.62 (M+). Anal. Calcd. for C33H24N2O3S: C, 74.98; H, 4.58; N, 5.30%. Found: C, 74.91; H, 4.65; N, 5.22%.
Hexahydro-3-phenyl-7-[(p-methyl)phenyl]spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4b. Yellow solid, mp 120–122 °C; IR (KBr) 3392, 1751, 1710, 1700 cm−1; 1H (300 MHz, CDCl3) δ 2.35 (s, 3H, Me); 3.15–3.19 (m, 1H, Hd1); 3.63–3.69 (m, 1H, Hd2); 4.34 (d, 1H, Ha, J = 9.3 Hz); 5.14–5.22 (m, 1H, Hb); 5.46 (s, 1H, Hc); 6.46–8.21 (m, 17H, ArH); 9.91 (s, 1H, NH). 13C (75 MHz, CDCl3) 26.4, 38.2, 55.4, 67.8, 71.5, 73.74 77.9, 109.2, 120.9, 122.5, 122.6, 124.4, 125.8, 127.2, 127.2, 127.5, 127.6, 128.0, 128.2, 128.4, 133.2, 135.2, 135.9, 140.5, 140.7, 141.1, 172.3, 192.9, 200.1. EI-MS m/z 542.65 (M+). Anal. Calcd. for C34H26N2O3S: C, 75.25; H, 4.83; N, 5.16%. Found: C, 75.19; H, 4.76; N, 5.22%.
Hexahydro-3-phenyl-7-[(p-methoxy)phenyl]spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4c. Yellow solid, mp 128–130 °C; IR (KBr) 3389, 1748, 1712, 1691 cm-1; 1H (300 MHz, CDCl3) δ 3.12–3.17 (m, 1H, Hd1); 3.67 (s, 3H, OMe); 3.69–3.73 (m, 1H, Hd2); 4.40 (d, 1H, Ha, J = 9.3 Hz); 5.11–5.19 (m, 1H, Hb); 5.32 (s, 1H, Hc); 6.42–8.27 (m, 17H, ArH); 9.96 (s, 1H, NH). 13C (75 MHz, CDCl3) 38.3, 55.1, 55.8, 68.5, 71.8, 73.9, 78.1, 109.5, 113.4, 122.3, 123.1, 124.9, 125.1, 127.1, 127.9, 128.1, 128.9, 129.1, 129.7, 135.6, 136.4, 139.4, 140.2, 140.8, 159.1, 172.8, 193.6, 200.3. EI-MS m/z 558.65 (M+). Anal. Calcd. for C34H26N2O4S: C, 73.10; H, 4.69; N, 5.01%. Found: C, C, 73.17; H, 4.77; N, 4.94%.
Hexahydro-3-phenyl-7-[(p-chloro)phenyl]spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4d. Yellow solid, mp 140–142 °C; IR (KBr) 3383, 1740, 1703, 1695 cm−1; 1H (300 MHz, CDCl3) δ 3.10–3.16 (m, 1H, Hd1); 3.66–3.73 (m, 1H, Hd2); 4.42 (d, 1H, Ha, J = 9.6 Hz); 5.12–5.20 (m, 1H, Hb); 5.31 (s, 1H, Hc); 6.45–8.24 (m, 17H, ArH); 8.90 (s, 1H, NH). 13C (75 MHz, CDCl3) 38.2, 55.5, 68.4, 71.6, 73.6, 77.8, 109.8, 122.4, 123.1, 123.2, 124.5, 127.1, 128.0, 128.2, 128.2, 128.9, 129.3, 129.9, 131.7, 133.8, 135.7, 136.5, 139.4, 140.1, 140.5, 140.9, 172.8, 193.4, 200.2. EI-MS m/z 563.07 (M+). Anal. Calcd. for C33H23ClN2O3S: C, 70.39; H, 4.12; N, 4.98%. Found: C, 70.46; H, 4.19; N, 4.94%.
Hexahydro-3-phenyl-7-[(p-bromo)phenyl]spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4e. Yellow solid, mp 138–140 °C; IR (KBr) 3396, 1743, 1710, 1699 cm−1; 1H (300 MHz, CDCl3) δ 3.06–3.11 (m, 1H, Hd1); 3.59–3.64 (m, 1H, Hd2); 4.33 (d, 1H, Ha, J = 9.6 Hz); 5.10–5.19 (m, 1H, Hb); 5.41 (s, 1H, Hc); 6.51–8.19 (m, 17H, ArH); 9.89 (s, 1H, NH). 13C (75 MHz, CDCl3) 38.1, 55.4, 67.7, 71.4, 72.7, 77.9, 109.4, 120.8, 122.4, 122.8, 124.0, 125.6, 127.2, 127.6, 127.7, 127.8, 128.1, 128.2, 128.5, 133.2, 135.2, 135.83, 140.5, 140.6, 141.0, 172.4, 192.8, 199.3. EI-MS m/z 607.52 (M+). Anal. Calcd. for C33H23BrN2O3S: C, 65.24; H, 3.82; N, 4.61%. Found: C, 65.16; H, 3.89; N, 4.56%.
Hexahydro-3-phenyl-7-[(p-nitro)phenyl]spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4f. Yellow solid, mp 152–154 °C; IR (KBr) 3383, 1739, 1705, 1696 cm−1; 1H (300 MHz, CDCl3) δ 3.30–3.36 (m, 1H, Hd1); 3.64–3.68 (m, 1H, Hd2); 4.52 (d, 1H, Ha, J = 9.6 Hz); 5.18–5.32 (m, 1H, Hb); 5.52 (s, 1H, Hc); 6.87–8.65 (m, 17H, ArH); 9.96 (s, 1H, NH).13C (75 MHz, CDCl3) 38.3, 55.3, 67.4, 71.6, 72.6, 78.5, 109.3, 121.3, 122.6, 123.5, 124.7, 126.9, 127.7, 127.9, 127.9, 128.0, 128.1, 128.3, 128.9, 133.7, 135.7, 136.1, 140.8, 140.7, 141.5, 172.6, 192.4, 200.6. EI-MS m/z 573.62 (M+). Anal. Calcd. for C33H23N3O5S: C, 69.10; H, 4.04; N, 7.33%. Found: C, 69.23; H, 4.13; N, 7.40%.
Hexahydro-3-phenyl-7-benzonitrile-spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4g. Pale yellow solid, mp 112–114 °C; IR (KBr) 3380, 2247, 1726, 1710, 1690 cm−1; 1H (300 MHz, CDCl3) δ 3.33–3.38 (m, 1H, Hd1); 3.70–3.75 (m, 1H, Hd2); 4.45 (d, 1H, Ha, J = 9.5 Hz); 5.20–5.35 (m, 1H, Hb); 5.61 (s, 1H, Hc); 6.99–8.77 (m, 17H, ArH); 9.93 (s, 1H, NH).13C (75 MHz, CDCl3) 38.3, 56.1, 67.7, 71.7, 72.7, 78.5, 110.0, 120.2, 122.3, 122.8, 123.6, 124.1, 125.9, 127.1, 128.2, 128.6, 128.9, 128.9, 129.0, 129.1, 133.7, 135.9, 136.8, 139.6, 140.1, 141.8, 173.4, 191.9, 199.9. EI-MS m/z 553.64 (M+). Anal. Calcd. for C34H23N3O3S: C, 73.76; H, 4.19; N, 7.59%. Found: C, 73.81; H, 4.22; N, 7.52%.
Hexahydro-3-phenyl-7-[(p-N,N′-dimethylamino)phenyl]spiro[5.2′]-2H-indene-1′,3′-dione-spiro[6.3″]oxindolopyrrolo[1,2-c]thiazole, 4h. Yellow solid, mp 166–168 °C; IR (KBr) 3386, 1728, 1706, 1689 cm−1; 1H (300 MHz, CDCl3) δ 3.11 (s, 6H); 3.32–3.34 (m, 1H, Hd1); 3.51–3.59 (m, 1H, Hd2); 4.48 (d, 1H, Ha, J = 9.6 Hz); 5.21–5.32 (m, 1H, Hb); 5.48 (s, 1H, Hc); 6.91–8.58 (m, 17H, ArH); 9.92 (s, 1H, NH).13C (75 MHz, CDCl3) 36.2, 37.1, 42.7, 56.8, 66.5, 70.6, 72.2, 77.9, 110.1, 121.8, 122.1, 123.5, 124.1, 125.9, 127.3, 127.9, 128.1, 128.1, 128.2, 128.3, 130.2, 133.6, 135.8, 136.3, 139.6, 140.6, 142.7, 174.1, 191.2, 199.9. EI-MS m/z 571.70 (M+). Anal. Calcd. for C35H29N3O3S: C, 73.53; H, 5.11; N, 7.35%. Found: C, 73.26; H, 5.23; N, 7.41%.
Environmentally green ACI/EG eutectic mixture mediated synthesis of novel substituted dispiropyrrolothiazole analogues through azomethineylide one-pot three component 1,3-dipolar cycloaddition reactions have been developed. This eutectic mixture mediated synthesis has the advantages of good to excellent yield, mild reaction conditions and with high regio- and stereo- selectivity. Further, the reusability of recovered eutectic mixture showed their stability and efficiency for the consecutive applications in synthesis. All the synthesized compounds were responding for commonly existing uropathogens, and 4a, 4d, and 4e showed highly proficient activities compared with other compounds. In addition, MIC tests of dispiropyrrolothiazole derivatives 4a–h were also examined by the tube dilution technique against most sensitive uropathogens viz. K. pneumonia, E. coli, and S. aureus and the results revealed that compounds 4d and 4e were effective against the uropathogens. The antioxidant activity of the synthesized compounds were assessed based on the scavenging activity of stable DPPH free radical. Interestingly, compounds 4a (IC50 = 35.30 μM), 4d (IC50 = 32.50 μM) and 4e (IC50 = 36.80 μM) showed effective free radical inhibition better than standard inhibitor BHA (IC50 = 58.60 μM). With additional optimization, we trust our compounds would be promising antimicrobial drugs for to treat against uropathogens causing urinary tract infections.
thin layer chromatography
Fourier-transform infrared spectroscopy
nuclear magnetic resonance
distortionless enhancement by polarization transfer
urinary tract infection
uropathogenic Escherichia coli
mimimum inhibitory concentration
brain heart infusion
- E. coli :
- K. pneumoniae :
- P. aeruginosa :
- S. aureus :
- E. faecalis :
American Type Culture Collection
- CDCI3 :
electron ionization mass spectrometry
Foxman B (2010) The epidemiology of urinary tract infection. Nat Rev Urol 7:653–660
Kulchavenia E, Breusov A (2011) Efficacy of uro-vaxom in recurrent infectious-inflammatory diseases of the urogenital system. Urologiia (Moscow, Russia: 1999) 4:7–11
Gupta K, Scholes D, Stamm WE (1999) Increasing prevalence of antimicrobial resistance among uropathogens causing acute uncomplicated cystitis in women. JAMA 281:736–738
Gastmeier P, Kampf G, Wischnewski NA, Hauer T, Schulgen G, Schumacher M, Daschner F, Rüden H (1998) Prevalence of nosocomial infections in representative german hospitals. J Hosp Infect 38:37–49
Flores-Mireles AL, Walker JN, Caparon M, Hultgren SJ (2012) Urinary tract infections: epidemiology, mechanisms of infection and treatment options. Nat Rev Microbiol 13:269–284
Murakami K, Aoki Y, Miyaji Y, Iwaoka K, Tsuka H, Saikawa S, Wada O, Gohbara M, Akino H, Mori H (1995) Statistical studies on organized isolated from urinary tract infections during a ten-year period. Nishinihon J Urol 57:1260–1264
Raguz S, Yagüe E (2008) Resistance to chemotherapy: new treatments and novel insights into an old problem. Br J Cancer 99:387
Cottrell DM, Capers J, Salem MM, DeLuca-Fradley K, Croft SL, Werbovetz KA (2004) Antikinetoplastid activity of 3-aryl-5-thiocyanatomethyl-1, 2, 4-oxadiazoles. Biorg Med Chem 12:2815–2824
Kumar A, Gupta G, Srivastava S, Bishnoi AK, Saxena R, Kant R, Khanna RS, Maulik PR, Dwivedi A (2013) Novel diastereoselective synthesis of spiropyrrolidine-oxindole derivatives as anti-breast cancer agents. RSC Adv 3:4731–4735
Mathusalini S, Arasakumar T, Lakshmi K, Lin C-H, Mohan PS, Ramnath MG, Thirugnanasampandan R (2016) Synthesis and biological evaluation of new spirooxindoles with embedded pharmacophores. New J Chem 40:5164–5169
Duthaler RO, Wyss B (2011) Conversion of l-cysteine into d-α-amino acids and related transformations. Eur J Org Chem 2011:4667–4680
Burgemeister T, Dannhardt G, Graf E, Obergrusberger R (1987) Perhydro-pyrrolo [2, 1-b] thiazolone: synthese und untersuchungen zu chemischen und pharmakologischen eigenschaften. Arch Pharm 32:799–806
Hasegawa M, Nakayama A, Yokohama S, Hosokami T, Kurebayashi Y, Ikeda T, Shimoto Y, Ide S, Honda Y, Suzuki N (1995) Synthesis and pharmacological activities of novel bicyclic thiazoline derivatives as hepatoprotective agents. Ii. (7-alkoxycarbonyl-2, 3, 5, 6-tetrahydropyrrolo [2, 1-b] thiazol-3-ylidene) acetamide derivatives. Chem Pharm Bull 43:1125–1131
Trapani G, Franco M, Latrofa A, Carotti A, Cellamare S, Serra M, Ghiani CA, Tuligi G, Biggio G, Liso G (1996) Synthesis and anticonvulsant activity of some 1, 2, 3, 3a-tetrahydropyrrolo [2, 1-b]-benzothiazol-,-thiazol-or-oxazol-1-ones in rodents. J Pharm Pharmacol 48:834–840
Jones JB, Young JM (1968) Carcinogenicity of lactones. Iii. The reactions of unsaturated. Gamma.-lactones with l-cysteine. J Med Chem 11:1176–1182
Butler DE, Leonard JD, Caprathe BW, L’Italien YJ, Pavia MR, Hershenson FM, Poschel PH, Marriott JG (1987) Amnesia-reversal activity of a series of cyclic imides. J Med Chem 30:498–503
Haddad S, Boudriga S, Porzio F, Soldera A, Askri M, Sriram D, Yogeeswari P, Knorr M, Rousselin Y, Kubicki MM (2014) Synthesis of novel dispiropyrrolothiazoles by three-component 1, 3-dipolar cycloaddition and evaluation of their antimycobacterial activity. RSC Adv 4:59462–59471
Sato S, Shibuya M, Kanoh N, Iwabuchi Y (2009) An expedient route to a potent gastrin/cck-b receptor antagonist (+)-AG-041R. J Org Chem 74:7522–7524
Kaminskyy D, Khyluk D, Vasylenko O, Zaprutko L, Lesyk R (2011) A facile synthesis and anticancer activity evaluation of spiro [thiazolidinone-isatin] conjugates. Sci Pharm 79:763–778
Reese L, Cutler K, Deutch C (1996) Sensitivity of escherichia coli to proline analogues during osmotic stress and anaerobiosis. Lett Appl Microbiol 22:202–205
Hashimoto T, Maruoka K (2015) Recent advances of catalytic asymmetric 1, 3-dipolar cycloadditions. Chem Rev 115:5366–5412
Nájera C, Sansano JM, Yus M (2015) 1, 3-dipolar cycloadditions of azomethine imines. Org Biomol Chem 13:8596–8636
da Costa JF, García-Mera X, Caamano O, Brea JM, Loza MI (2015) Synthesis by microwave-assisted 1, 3-dipolar cycloaddition of 1, 2, 3-triazole 1′-homo-3′-isoazanucleosides and evaluation of their anticancer activity. Eur J Med Chem 98:212–220
Harju K, Yli-Kauhaluoma J (2005) Recent advances in 1, 3-dipolar cycloaddition reactions on solid supports. Mol Divers 9:187–207
Nagendrappa G (2011) Organic synthesis using clay and clay-supported catalysts. Appl Clay Sci 53:106–138
Li X, Chen X, Jiang Y, Chen S, Qu L, Qu Z, Yuan J, Shi H (2016) Highly efficient ultrasonic-assisted CuCl-catalyzed 1, 3-dipolar cycloaddition reactions in water: synthesis of coumarin derivatives linked with 1, 2, 3-triazole moiety. J Heterocycl Chem 53:1402–1411
Martins MAP, Frizzo CP, Tier AZ, Moreira DN, Zanatta N, Bonacorso HG (2014) Update 1 of: eutectic mixtures in heterocyclic synthesis. Chem Rev 114:PR1–PR70
Dandia A, Jain AK, Sharma S (2012) An efficient and highly selective approach for the construction of novel dispiro heterocycles in guanidine-based task-specific [TMG][AC] eutectic mixture. Tetrahedron Lett 53:5859–5863
Periyasami G, Arumugam N, Aldalbahi A (2017) Inexpensive eutectic mixture mediated green synthetic approach of multi-functionalized regioselective β-lactam fused isoxazolidine heterocyclic hybrids. Tetrahedron 73:322–330
Huynh-Ba T, Matthey-Doret W, Fay LB, Bel-Rhlid R (2003) Generation of thiols by biotransformation of cysteine-aldehyde conjugates with baker’s yeast. J Agric Food Chem 51:3629–3635
Periyasami G, Arumugam N, Rahaman M, Kumar RS, Manikandan M, Alfayez MA, Premnath D, Aldalbahi A (2018) ACI/EG eutectic mixture mediated synthesis, characterization and in vitro osteoblast differentiation assessment of spiropyrrolo [1, 2-b] isoquinoline analogues. RSC Adv 8:16303–16313
Zhang Q, Vigier KDeV, Royer S, Jerome F (2012) Deep eutectic solvents: syntheses, properties and applications. Chem Soc Rev 41:7108–7146
Arumugam N, Almansour AI, Suresh kumar R, Periyasami G, Al-thamili DM, Rajapandian K, Periyasami VS, Alshatwi AA, Mahalingam SM, Shankar T, Menendez JC (2018) Multicomponent domino synthesis, anticancer activity and molecular modeling simulation of complex dispirooxindolopyrrolidines. Molecules 23:1094–1110
Suresh kumar R, Antonisamy P, Almansour AI, Arumugam N, Periyasami G, Altaf M, Kim H-R, Kwon K-B (2018) Functionalized spirooxindole-indolizine hybrids: Stereoselective green synthesis and evaluation of anti-inflammatory effect involving TNF-α and nitrite inhibition. Eur J Med Chem 152:417–423
Ku S-Y, Lu S-Y (2011) Inexpensive room temperature eutectic mixtures for low volatility electrolytes of dye-sensitized solar cells. Int J Electrochem Sci 6:5219–5227
López V, Jäger AK, Akerreta S, Cavero RY, Calvo MI (2011) Pharmacological properties of anagallis arvensis l. (“scarlet pimpernel”) and anagallis foemina mill. (“blue pimpernel”) traditionally used as wound healing remedies in navarra (spain). J Ethnopharmacol 134:1014–1017
Testing (2000) ECOAS Of the european society of clinical microbiology and infectious diseases (escmid). Determination of minimum inhibitory concentrations (mics) of antibacterial agents by agar dilution. Clin Microbiol Infect 6:509–515
Duan X-J, Zhang W-W, Li X-M, Wang B-G (2006) Evaluation of antioxidant property of extract and fractions obtained from a red alga, Polysiphonia urceolata. Food Chem 95:37–43
GP designed, synthesis, characterized the compounds and wrote the manuscript. KP and NAA carried out the antimicrobial studies and wrote the corresponding results and discussion. NA and RSK contributed to one and/or other part of the experimental and spectroscopic studies and also in manuscript writing. DP and SA carried out the literature survey, synthesizing and purification the compounds and contributing the manuscript preparation. MR and AA contributed to revise and finalizing the manuscript. All authors read and approved the final manuscript.
Authors are express their appreciation to the Deanship of Scientific Research at King Saud University for their support to complete this research. Also, GP thank to the University of Madras for providing research facilities for the initial work.
The authors declare that they have no competing interests.
Availability of data and materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Ethics approval and consent to participate
Deanship of Scientific Research at King Saud University through research group no. RG-1436-005.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Periyasami, G., Ponmurugan, K., Arumugam, N. et al. An expeditious and environmentally benign synthesis of dispiro-3-phenylpyrrolothiazoles in ACI/EG eutectic mixture and its antioxidant and antimicrobial activities against urinary tract pathogens. BMC Chemistry 13, 42 (2019). https://doi.org/10.1186/s13065-019-0553-3
- Eutectic mixture
- Green protocol