Bioorganic Chemistry 86 (2019) 624–630 Contents lists available at ScienceDirect Bioorganic Chemistry journal homepage: www.elsevier.com/locate/bioorg Synthesis of sulfonamide, amide and amine hybrid pharmacophore, an entry T of new class of carbonic anhydrase II inhibitors and evaluation of chemo- informatics and binding analysis ⁎ Attique Ahmeda, Pervaiz Ali Channara, Aamer Saeeda, , Markus Kalesseb, Mehar Ali Kazic, Fayaz Ali Larika, Qamar Abbasd, Mubashir Hassane, Hussain Razae, Sung-Yum Seoe a Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan b Institut für Organische Chemie, Schneiderberg 1 B, 30167 Hannover, Germany c Institute of Biochemistry, University of Sindh, Jamshoro 76080, Pakistan d Department of Physiology, University of Sindh, Jamshoro 76080, Pakistan e Department of Biological Sciences, College of Natural Sciences, Kongju National University, 56 Gongjudehak-Ro, Gongju, Chungnam 32588, Republic of Korea ARTICLE INFO ABSTRACT Keywords: Selective inhibition of carbonic anhydrase (CA) enzyme is an active area of research for medicinal chemists. In Carbonic anhydrase II inhibition the current account, a hybrid pharmacophore approach was employed to design sulfonamide, amide and amine Synthesis containing new series of potent carbonic anhydrase II inhibitors. The aromatic fragment associated with phar- Hybrid pharmacophore macophore was altered suitably in order to find effective inhibitors of CA-II. All the derivatives 4a-4m showed Binding analysis better inhibition compared to the standard acetazolamide. In particular, compound 4l exhibited significant Chemo-informatics inhibition with IC50 value of 0.01796 ± 0.00036 µM. The chemo-informatics analysis justified that all the de- signed compounds possess < 10 HBA and < 5 HBD. The ligands-protein binding analyses showed that 4l con- fined in the active binding pocket with three hydrogen bonds observed with His63, Asn66 and Thr197 residues. 1. Introduction chemists because designing of inhibitors of CA play important role in the treatment of epilepsy, glaucoma, idiopathic intracranial hyperten- The carbonic anhydrases (CAs, E.C. 4.2.1.1) are a group of zinc sion and altitude sickness. metal containing metalloenzymes pervasive in nature. The three most Sulfonamides possess many types of biological activities, and re- prevalent isoforms in nature include, α-CAs (present in vertebrates, presentatives of this class of pharmacological agents are widely used in eubacteria, algae and cytoplasm of green plants), the β-CAs (pre- clinic as antibacterial, hypoglycemic, diuretic, anti-hypertensive and dominantly in eubacteria, algae and chloroplasts of both mono- as well antiviral drugs among others [11–17]. Sulfonamides (R-SO2NH2 possess as dicotyledons) and the γ-CAs (mainly in archaea and some eu- great significance in the designing of CA inhibitors mainly due tothe bacteria). In higher vertebrates including humans, the different car- unique and tailor ability of binding with CA protein which is driven by bonic anhydrase isozymes include cystolic forms (CA I-III, CA VII), four coordination of the deprotonated sulfonamide nitrogen to the catalytic membrane bound isozymes (CA IV, CA IX, CA XII and CA XIV), one zinc ion (Zn2+), additional interactions with the hydrophilic and/or mitochondrial form (CA V) and one secreted CA isozyme, CA VI [1–6]. hydrophobic region of the active site may take place, depending on the The carbonic anhydrase catalyze an apparently simple physiological nature of the substituent group. After the first report of the scientific − + interconversion (CO2 + H2O ⇌ HCO3 + H ) yet this simple reaction evidence of sulfanilamide as inhibitor of CA enzymes [18], it was is involved in the crucial process of respiration and transport of CO2/ suggested that unsubstituted aromatic sulfonamides of type ArSO2NH2 bicarbonate between metabolizing tissues and lungs, pH and CO2 act as strong CAIs (carbonic anhydrase inhibitors) which led to the homeostasis, electrolyte secretion in a variety of tissues/organs, bio- discovery of several new drug candidates. Currently, a number of re- synthetic reactions (such as gluconeogenesis, lipogenesis and ureagen- search groups are actively involved in the design and discovery of esis), bone resorption, calcification, and tumorigenicity [7–10]. The CA sulfonamides as carbonic anhydrase inhibitors [19–23]. Despite sub- isozymes have been the active area of research among medicinal stantial synthetic efforts, it is rather difficult to achieve high isozyme ⁎ Corresponding author. Tel.: +92-51-9064-2128; fax: +92-51-9064-2241. E-mail addresses: [email protected] (A. Saeed), [email protected] (F.A. Larik). https://doi.org/10.1016/j.bioorg.2019.01.060 Received 25 September 2018; Received in revised form 12 January 2019; Accepted 27 January 2019 Available online 10 February 2019 0045-2068/ © 2019 Elsevier Inc. All rights reserved. A. Ahmed, et al. Bioorganic Chemistry 86 (2019) 624–630 selectivity in vitro with classical designs incorporating aromatic/het- 149.62, 141.92, 138.79, 134.36, 130.44, 127.07, 119.04, 117.05, erocyclic primary sulfonamides and sulfamates due to sequence 112.43, 111.25, 47.91 (CH2). homology and thus structural similarities that exist between different N-(4-sulfamoylphenyl)-2-((4-sulfamoylphenyl)amino)acet- CA isozymes in their active sites. amide (4b): Selective inhibition of carbonic anhydrase II constitutes a viable White solid, m.p. = 290–293 °C, yield = 61%, Rf = 0.41 1 approach to fight against the disorders caused by harmful effects ofCA (Chloroform: Methanol 4:1); H NMR (DMSO‑d6): δ (ppm) 8.89 (s, 1H, II enzyme [24]. Building on these premises and taking into account the NH), 7.80 (broad s, 8H, Ar-H), 7.53(s, 2H, SO2NH2), 6.65 (s, 2H, 13 fact that the amide functionality also possesses the ability to interact SO2NH2) 5.10 (t, 1H, NH, J = 5.3), 4.0 (d, 2H, CH2, J = 5.3). C NMR: with active site of CA II through hydrogen bonding, besides sulfona- (75 MHz DMSO‑d6) δ (ppm) 172.22 (C]O), 158.72, 142.77, 138.99, mide, and incorporation of amine in the target compounds can further 135.66, 133.84, 128.09, 120.03, 116.08, 113.45, 112.35, 49.31 (CH2). enhance their aptitude to bind effectively. We herein report a hybrid N-(4-sulfamoylphenyl)-2-(p-tolylamino)acetamide (4c): pharmacophoric approach involving coupling of sulfonamide, amide Light brown solid, m.p. = 254–256 °C, yield = 69%, Rf = 0.63 1 and amine as three distinct pharmacophoric entities possessing intri- (Chloroform: Methanol 4:1); H NMR DMSO‑d6): δ (ppm) 9.22 (s, 1H, guing structural features such as C]O, S]O, NH2 and NH group. NH), 7.97 (s, 4H, Ar-H), 7.21 (d, 2H, J = 7.9 Hz, Ar-H), 6.50 (d, 2H, Furthermore we altered the aromatic part with different groups and J = 7.8 Hz, Ar-H), 6.40 (s, 2H, SO2NH2), 5.92 (t, 1H, NH, J = 5.2), 4.1 13 also used commercial drugs like amantadine. In addition, we explored (d, 2H, CH2, J = 5.2,). C NMR: (75 MHz DMSO‑d6) δ (ppm) 168.62 the potential of synthesized compounds against carbonic II anhydrase (C]O), 144.68, 141.72, 137.59, 128.62, 128.24, 118.09, 113.04, 44.61 enzyme and also provided close in silico insights of binding analysis and (CH2). chemo-informatics. 2-((4-chlorophenyl)amino)-N-(4-sulfamoylphenyl)acetamide (4d): 2. Experimental Light brown solid, m.p. = 257–258 °C, yield = 71%, Rf = 0.67 1 (Chloroform: Methanol 4:1); H NMR (DMSO‑d6): δ (ppm) 9.19 (s, 1H, 2.1. All chemicals NH), 8.01 (s, 4H, Ar-H), 7.56 (d, 2H, J = 7.7 Hz, Ar-H), 6.64 (d, 2H, J = 7.7 Hz, Ar-H), 6.53 (s, 2H, SO2NH2), 5.70 (t, 1H, NH, J = 5.3), 4.07 13 reagents, were purchased from Sigma-Aldrich Chemical Co. or (d, 2H, CH2, J = 5.3). C NMR: (75 MHz DMSO‑d6) δ (ppm) 169.02 Merck, Germany, and were used without further purification. The sol- (C]O), 146.70, 142.51, 136.39, 131.12, 129.14, 125.81, 117.41, vents were dried and distilled prior to use. The Rf values were de- 115.32, 46.71 (CH2). termined using aluminium pre-coated silica gel plates Kiesel 60F254 (S)-2-((2-oxo-2-((4-sulfamoylphenyl)amino)ethyl)amino)penta- from Merck (Darmstadt, Germany). The melting points of the com- nedioic acid (4e) pounds were measured in open capillaries using a Stuart melting point White solid, m.p. = 233–235 °C, yield = 57%, Rf = 0.46 1 apparatus (SMP3) and are uncorrected. The FT IR spectra were re- (Chloroform: Methanol 4:1); H NMR (DMSO‑d6): δ (ppm) 10.6 (broad corded on an FTS 3000 MX, Bio-Rad Merlin (Excalibur Model) spec- s, 1H, COOH), 10.4 (broad s, 1H, COOH), 9.33 (broad s, 1H, NH), 7.81 trophotometer as pure compounds. The 1H and 13C NMR spectra were (d, 2H, J = 7.3 Hz, Ar-H), 6.97 (d, 2H, J = 7.3 Hz, Ar-H), 6.63(s, 2H, 13 acquired on a Bruker NMR spectrometer at 300 MHz and 75.5 MHz SO2NH2), 5.70 (t, 1H, NH, J = 5.3), 3.91 (d, 2H, CH2, J = 5.3). C using TMS as an internal standard. Mass spectra were recorded on an NMR: (75 MHz Acetone‑d6) δ (ppm) 175.12 (C]O), 179.23 (C]O), Agilent Technologies 6890N gas chromatograph equipped with an inert 167.14, (C]O), 145.52, 138.19, 131.16, 118.04, 64.08(CH), 48.17 mass selective detector (5973 mass spectrometer), and elemental ana- (CH2). 31.7, 28.32 lyses were conducted using a LECO-183 CHNS analyser. 2-((2-chlorophenyl)amino)-N-(4-sulfamoylphenyl)acetamide (4f): 2.2. Synthesis of 2-chloro-N-(4-sulfamoylphenyl) acetamide (3) Light brown solid, m.p.