Journal of Enzyme Inhibition and Medicinal Chemistry

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Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives as antihyperglycaemic agents and inhibitors of aldose reductase – an enzyme embroiled in diabetic complications Raed Yaseen, H. Pushpalatha, G. Bhanuprakash Reddy, Ameer Ismael, Ayad Ahmed, Alhamza Dheyaa, Syed Ovais, Pooja Rathore, Mohammed Samim, Mymoona Akthar, Kalicharan Sharma, Syed Shafi, Surender Singh & Kalim Javed To cite this article: Raed Yaseen, H. Pushpalatha, G. Bhanuprakash Reddy, Ameer Ismael, Ayad Ahmed, Alhamza Dheyaa, Syed Ovais, Pooja Rathore, Mohammed Samim, Mymoona Akthar, Kalicharan Sharma, Syed Shafi, Surender Singh & Kalim Javed (2016): Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives as anti-hyperglycaemic agents and inhibitors of aldose reductase – an enzyme embroiled in diabetic complications, Journal of Enzyme Inhibition and Medicinal Chemistry, DOI: 10.3109/14756366.2016.1142986 To link to this article: http://dx.doi.org/10.3109/14756366.2016.1142986

Published online: 16 Feb 2016.

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Date: 20 February 2016, At: 11:12

http://informahealthcare.com/enz ISSN: 1475-6366 (print), 1475-6374 (electronic) J Enzyme Inhib Med Chem, Early Online: 1–13 ! 2016 Taylor & Francis. DOI: 10.3109/14756366.2016.1142986

RESEARCH ARTICLE

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives as anti-hyperglycaemic agents and inhibitors of aldose reductase – an enzyme embroiled in diabetic complications

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Raed Yaseen1, H. Pushpalatha2, G. Bhanuprakash Reddy2, Ameer Ismael3, Ayad Ahmed3, Alhamza Dheyaa1, Syed Ovais1, Pooja Rathore1, Mohammed Samim1, Mymoona Akthar4, Kalicharan Sharma4, Syed Shafi1, Surender Singh5, and Kalim Javed1 1

Department of Chemistry, Faculty of Science, Jamia Hamdard (Hamdard University), New Delhi, India, 2Biochemistry Division, National Institute of Nutrition, Hyderabad, India, 3Department of Pharmacology, State Company for Drugs Industry and Medical Appliances, Samarra, Iraq, 4 Drug Design and Medicinal Chemistry Laboratory, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Jamia Hamdard (Hamdard University), New Delhi, India, and 5Department of Pharmacology, All India Institute of Medical Sciences, New Delhi, India Abstract

Keywords

Thirty new aryl-pyridazinone-substituted benzenesulphonylurea derivatives (I–XXX) were synthesized and evaluated for their anti-hyperglycaemic activity in glucose-fed hyperglycaemic normal rats. Twenty-three compounds (III–XI, XIV–XVII, XIX–XXIV, XXVI and XXVIII–XXX) showed more or comparable area under the curve (AUC) reduction percentage (ranging from 21.9% to 35.5%) as compared to the standard drug gliclazide (22.0%). On the basis of docking results, 18 compounds were screened for their in vitro ability to inhibit rat lens aldose reductase. Ten compounds (III–VI, XII, XVI–XVIII, XXI and XXVII) showed ARI activity with IC50 ranging from 34 to 242 mM. Out of these, two compounds IV and V showed best ARI activity which is comparable with that of quercetin. As a result, two compounds (IV and V) possessing significant dual action (anti-hyperglycaemic and aldose reductase inhibition) were identified and may be used as lead compounds for developing new drugs.

Aldose reductase, diabetes, docking, pyridazinone, sulfonylurea

Introduction Diabetes mellitus (DM) has become pandemic and according to reports, including a forecast by the World Health Organizations (WHO), there will be a sharp increase in the total number of cases world wide by 2030. In fact, India could be bracing itself for the dubious distinction of becoming the diabetes of capital of the world1. Alone, in India recently published report by ICMRINDIAB national study stated that there are 62.4 million people with non-insulin-dependent diabetes mellitus (NIDDM) and 77 million people with prediabetes in India. NIDDM is the most common form of diabetes and has been found 90% of all diabetes2. NIDDM is a multifactorial metabolic disease characterized by abnormalities at multiple organ sites. These defects include insulin resistance and insulin deficiency3,4. The former is primarily represented by decreased insulin-stimulated glucose uptake in skeletal muscle, augmented endogenous glucose production (predominately in the liver) and enhanced lipolytic activity in fat5. The latter is an apparent progressive process with both functional defects in islet cell function and, eventually, Address for correspondence: Kalim Javed, Department of Chemistry, Jamia Hamdard (Hamdard University), New Delhi, India. E-mail: [email protected]

History Received 16 December 2015 Revised 10 January 2016 Accepted 11 January 2016 Published online 11 February 2016

apparent loss of b-cell mass6,7. These defects are intimately linked with derangements in one system exacerbating those in the others8. Patients with DM are at high risk of developing long-term complications including neuropathy, nephropathy, retinopathy and cataract9,10. Although strict glycaemic control is expected to prevent diabetic complications but perfect glycaemic control is not always possible. In hyperglycaemic conditions, aldose reductase catalyses an NADPH-dependent reduction of glucose to sorbitol, which in turn is oxidized to fructose by an NAD+dependent sorbitol dehydrogenase (Figure 1). Once sorbitol is accumulated inside the cells, it cannot diffuse easily across the cell membrane as a result osmotic pressure increases causing cellular damage. Moreover, the depletion of NADPH and NAD+ cofactors compromises body’s antioxidant defence system. In addition, high blood levels of fructose may account for increased glycation and accelerating ageing11,12 (Figure 1). Thus, inhibition of AR is one of the important targets and its inhibition could be the key for the treatment of many diabetic complications13. Aldose reductase inhibitors (ARIs) have been shown to reduce tissue sorbitol accumulation in diabetic animals14 and there are evidences that blockage of AR can have beneficial effect in diabetic complications15,16. Various structurally different compounds have been identified as potent in vitro ARIs and some of them are in clinical trials to

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Figure 1. Polyol metabolic pathway of glucose and its side effects.

test their efficacy in the prevention and treatment of peripheral neuropathy in diabetes10,17. They can be categorized into various groups based on their chemical structures: acetic acid derivatives (e.g. epalrestat, Imirestat), cyclic imides (especially spirohydantoins, e.g. sorbinil, fidarestat) etc. Despite being structurally different, all ARIs possess the following two peculiar pharmacophoric elements: (i) an acidic moiety that is able to interact with the ‘‘anion-binding site’’ of the catalytic site and (ii) a lipophilic scaffold that can bind to the highly flexible specificity pocket of the catalytic site18. Our interest in studying the molecular determinants for binding to the aldose reductase inhibitor site led us to study the aldose reductase inhibitory activity of target compounds possessing benzenesulphonylurea as carboxylic acid surrogates. Besides this benzenesulphonamide derivatives have been already reported as ARI19,20. The SO2 group of the benzenesulphonamide forms the hydrogen bond with the amino acid residues of the anionic binding site of the AR enzyme21. In curing, diabetes sulphonyl ureas have represented the backbone of oral therapy in NIDDM for more than 40 years22. Recently, compounds containing pyridazinone nucleus have been reported as AR inhibitors23–26. In the view of above facts and as part of our research programme (to develop new lead compounds that not only act as antihyperglycaemic agents, but at the same time prevent diabetic complications caused by the aldose reductase or the associated pathway), we herein report the synthesis of new pyridazinone-substituted benzenesulphonyl urea derivatives (I–XXX) incorporating with known bioactive moieties highlighted in Figure 2. We have introduced a diversity of arylsubstituted pyridazinones moiety at para position of benzenesulphonamide and other substitutions, such as isopropyl and 4-methylcyclohexyl groups, were made at N2 position of the uriedo group, keeping the core structure intact (Figure 2). The synthesized compounds (I–XXX) were evaluated for antihyperglycaemic effects in glucose-fed hyperglycaemic normal rats. In silico molecular docking studies of these compounds (I–XXX) were performed with respect to aldose reductase. Eighteen compounds displaying good docking results were evaluated for their ability to inhibit rat lens aldose reductase.

(J values) are expressed in hertz (Hz). Elemental analysis was carried out on CHNS Elementar (Vario EL III). Mass spectra (MS) were scanned by using ESI Bruker Esquire 3000 (Billerica, MA). The m/z values of the more intense peaks are mentioned. General procedure for synthesis of sulfonylureas (I-XXX) A solution of appropriate pyridazinone (1 mmol) in dry acetone was refluxed over anhydrous K2CO3 (2 mmol) for 1–1.5 h. At this temperature, a solution of the appropriate isocyanate (1.2 mmol) in dry acetone 5 ml was added in a dropwise manner. It was refluxed for 24–72 h. Acetone was removed under reduced pressure. The solid residue thus obtained was suspended in water and acidified with dilute acetic acid. It was stirred for 30 min and filtered. The residue was washed with plenty of distilled water in order to make the residue free from potassium acetate. It was dried and crystallized from methanol. The purity of the compounds was checked on TLC plate (Silica gel G) in the solvent system toluene/ethyl acetate/formic acid (5:4:1, TEF). 1-{4-[3–(2,3-Dihydro-1H-inden-5-yl)-6-oxopyridazin-1yl]benzenesulphonyl}-3-isopropylurea (I) Yellow crystals, yield ¼ 45%, m.p. 120–121  C, Rf ¼ 0.65 (TEF). IR  max (KBr, in cm 1): 3335, 3037 and 2911 (NH-CO-NH), 1715 and 1525 (C¼O) of urea, 1605 (C¼N), 1320 and 1142 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.95 (6H, d, J ¼ 6 Hz, -CH-(CH3)2), 1.90–2.07 (2H, m, H-3000 ), 2.91 (4H, d, J ¼ 4.2 Hz, H-2000 , H-4000 ), 3.53–3.66 (1H, m, -NH-CH-(CH3)2), 5.49 (1H, brs, -NH-(CH3)2), 7.14–8.15 (9H, m, H-5, H-50 , H-60 , H-20 , H-300 , H500 , H-200 , H-600 , H-4), 8.31 (1H, s, SO2-NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 43.20 (CH-NH), 125.71 (C-4 pyridazinone), 137.60 (C¼O uriedo group), 144.22 (C-5 pyridazinone), 152.10 (C¼O pyridazinone), 155.62 (C¼N pyridazinone). ESI-MS (m/z): 452 [M+], 453 [M + 1], 451 [M-1], 450 [M-2]. CHNS Analysis for C23H24N4O4S Found (Calculated): C: 61.10 (61.08), H: 5.34 (5.39), N: 12.38 (12.30), O: 14.12(14.15), S: 7.07 (7.13).

Experimental

3-Isopropyl-1–(4-{3-[4–(2-methylpropyl)phenyl]-6-oxopyridazin-1-yl} benzenesulphonyl) urea (II)

Melting points were determined by open capillary tubes and are uncorrected. Purity of the compounds was checked on thin-layer chromatography (TLC) plates (silica gel G) that were visualized by exposing to iodine vapours. Infrared (IR) spectra were recorded (in KBr) on a BIO-RAD FTS-135 spectrophotometer and 1HNMR spectra were recorded on a Bruker Spectrospin DPX 300 MHz spectrometer using deuterated dimethyl sulphoxide (DMSO) as solvent and tetramethyl silane (TMS) as an internal standard. Chemical shifts are given in d (ppm) scale and coupling constants

Yellow crystals, yield ¼ 47%, m.p. 162–163  C, Rf ¼ 0.67 (TEF). IR  max (KBr, in cm 1): 3360, 3025 and 2915 (NH-CO-NH), 1710 and 1510 (C¼O) of urea, 1596 (C¼N), 1325 and 1155 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.87 (6H, d, J ¼ 6.6 Hz, Ph-CH2-CH-(CH3)2), 0.98 (6H, d, J ¼ 8.1 Hz, -NHCH-(CH3)2), 1.88 (1H, m, Ph-CH2-CH-(CH3)2), 2.5 (2H, merged s, Ph-CH2-CH-(CH3)2), 3.58–3.67 (1H, m, -NH-CH-(CH3)2), 5.46 (1H, d, J ¼ 4.5 Hz, -NH-CH-(CH3)2), 7.20 (1H, d, J ¼ 10.2 Hz, H-5), 7.29 (2H, d, J ¼ 6.9 Hz, H-30 , H-50 ), 7.62

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives

DOI: 10.3109/14756366.2016.1142986

O O

R

3

R' N

S

R''

O N 19,20 ARIs

N COOH O

O

R Calf lens aldose reductase inhibitor

S

N

23 N Ar

O H N

H N

C

R

O Target compounds (I-XXX)

O N N

COOH

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O R1

O H N

S

C

H N

R2

O Cl Pig lens aldose reductase inhibitor

Clinically used anti-diabetic Sulphonylureas 25

Tolbutamide Chlorpropamide

R1

R2

CH3

C4H9

Cl

C3H7

Acetohexmide

CH3CO

Tolazamide

CH3

N

Gliclazide

CH3

N

C6H11

CONHCH2CH2

Glibenclamide

C6H11

Figure 2. Structures of clinically used antidiabetic drugs and pyridazinone derivatives reported as aldose reductase inhibitor. Rationally designed template for targeted compound (I–XXX).

(1H, d, J ¼ 9.8 Hz, -SO2-NH-C¼O), 7.85 (2H, d, J ¼ 7.2 Hz, H20 , H-60 ), 7.90 (2H, d, J ¼ 7.8 Hz, H-300 , H-500 ), 7.96 (2H, d, J ¼ 8.4 Hz, H-200 , H-600 ), 8.14 (1H, d, J ¼ 9.9 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 43.25 (CH-NH), 125.74 (C-4 pyridazinone), 137.62 (C¼O uriedo group), 144.35 (C-5 pyridazinone), 151.20 (C¼O pyridazinone), 156.44 (C¼N pyridazinone). ESI-MS (m/z): 468 [M+], 469 [M + 1], 467 [M-1], 466 [M2].CHNS Analysis for C24H28N4O4S Found (Calculated): C: 61.55 (61.56), H: 6.05 (6.08) N: 12.10 (12.15), O: 13.54 (13.59), S: 6.85 (6.90). 1-{4-[3–(3,4-Difluorophenyl)-6-oxopyridazin-1-yl]benzenesulphonyl}-3-isopropylurea (III) Light brown crystals, yield ¼ 51% m.p. 142–143  C, Rf ¼ 0.60 (TEF). IR  max (KBr, in cm 1): 3345, 3033 and 2940 (NH-CONH), 1698 and 1515 (C¼O) of urea, 1613 (C¼N), 1331 and 1151 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.93 (6H, d,

J ¼ 6.5 Hz, -CH-(CH3)2), 3.75–3.84 (1H, m, -NH-CH-(CH3)2), 6.60 (1H, d, J ¼ 5.4 Hz, -NH-CH-(CH3)2), 7.46 (1H, d, J ¼ 7.2 Hz, H-5), 7.78 (1H, dd, J ¼ 7.8 Hz, H-50 ), 8.04 (1H, d, J ¼ 6 Hz, H-20 ), 8.17 (2H, d, J ¼ 6.3 Hz, H-300 , H-500 ), 8.22–8.28 (3H, m, H-60 , H-200 , H-600 ), 8.40 (1H, d, J ¼ 7.5 Hz, H-4), 10.75 (1H, s, SO2-NH-C¼O). 13 C NMR (75 MHz, DMSO-d6, d, ppm): 43.22 (CH-NH), 125.67 (C-4 pyridazinone), 138.60 (C¼O uriedo group), 145.31 (C-5 pyridazinone), 151.17 (C¼O pyridazinone), 155.54 (C¼N pyridazinone). ESI-MS (m/z): 448 [M+], 449 [M + 1], 447 [M-1], 446 [M-2]. CHNS Analysis for C20H18F2N4O4S Found (Calculated): C: 53.58 (53.59), H: 4.08 (4.09), F: 8.48 (8.49), N: 12.48 (12.49), O: 14.28 (14.29), S: 7.13 (7.14). 1-{4-[3–(4-Fluorophenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-3-isopropylurea (IV) Yellow crystals, yield ¼ 41%, m.p. 102–103  C, Rf ¼ 0.60 (TEF). IR  max (KBr, in cm1): 3327, 3050 and 2970 (NH-CO-NH),

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1705 and 1503 (C¼O) of urea, 1597 (C¼N), 1339 and 1157 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.99 (6H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 3.61–3.69 (1H, m, -NH-CH-(CH3)2), 4.10 (1H, d, J ¼ 5.7 Hz, -NH-CH-(CH3)2), 7.06 (1H, d, J ¼ 9.6 Hz, H-5), 7.12 (2H, d, J ¼ 9 Hz, H-20 , H-60 ), 7.74–7.96 (6H, m, H-30 , H-50 , H-300 , H-500 , H-200 , H-600 ), 8.01 (1H, d, J ¼ 8.7 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 42.91 (CH-NH), 125.40 (C-4 pyridazinone), 137.20 (C¼O uriedo group), 146.10 (C-5 pyridazinone), 152.10 (C¼O pyridazinone), 155.31 (C¼N pyridazinone). ESI-MS (m/z): 430 [M+], 431 [M + 1], 429 [M-1], 428 [M-2].CHNS Analysis for C20H19FN4O4S Found (Calculated): C: 55.75 (55.76), H: 4.43 (4.44), F: 4.39 (4.4), N: 13.10 (13.12), O: 14.87 (14.88), S: 7.46 (7.47).

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3-Isopropyl-1-{4-[6-oxo-3–(5, 6, 7, 8-tetrahydronaphthalen-2-yl) pyridazin-1-yl] benzenesulphonyl} urea (V) White crystals, yield ¼ 45%, m.p. 200–201  C, Rf ¼ 0.63 (TEF). IR  max (KBr, in cm1): 3356, 3071 and 2995 (NH-CO-NH), 1720 and 1518 (C¼O) of urea, 1610 (C¼N), 1345 and 1175 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 1.01 (6H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 1.76 (4H, brs, H-3000 , H-4000 ), 2.77 (4H, brs, H-2000 , H-5000 ), 3.59–3.61 (1H, m, -NH-CH-(CH3)2), 5.50 (1H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 6.27 (1H, d, J ¼ 15.6 Hz, SO2-NH-C¼O), 6.97–7.28 (2H, m, H-5, H-50 ), 7.64–7.75 (2H, m, H-20 , H-60 ), 7.90 (2H, d, J ¼ 8.1 Hz, H-300 , H-500 ), 8.01 (2H, d, J ¼ 6.9 Hz, H-200 , H-600 ), 8.15 (1H, d, J ¼ 9.6 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 43.65 (CH-NH), 125.22 (C-4 pyridazinone), 138.52 (C¼O uriedo group), 145.10 (C-5 pyridazinone), 151.37 (C¼O pyridazinone), 155.72 (C¼N pyridazinone). ESI-MS (m/z): 466 [M+], 467 [M + 1], 465 [M-1], 464 [M2].CHNS Analysis for C24H26N4O4S Found (Calculated): C: 61.75 (61.74), H: 5.62 (5.60), N: 12.10 (12.11), O: 13.70 (13.72), S: 6.91(6.92). 1-{4-[3–(4-Benzylphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-3-isopropylurea (VI) Light yellow crystals, yield ¼ 58%, m.p. 179–180  C, Rf ¼0.61 (TEF). IR  max (KBr, in cm 1): 3340, 3049 and 2998 (NH-CONH), 1705 and 1522 (C¼O) of urea, 1596 (C¼N), 1355 and 1153 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 1.02 (6H, d, J ¼ 8.4 Hz, -NH-CH-(CH3)2), 3.56–3.64 (1H, m, -NH-CH(CH3)2), 4.01 (2H, s, Ph-CH2-Ph), 6.39 (1H, s, -NH-CH(CH3)2), 7.18–7.32 (6H, m, H-2000 , H-3000 , H-4000 , H-5000 , H-6000 , H-5), 7.37 (2H, d, J ¼ 6.3 Hz, H-30 , H-50 ), 7.87 (2H, d, J ¼ 6 Hz, H-20 , H-60 ), 7.95 (2H, d, J ¼ 6.3 Hz, H-300 , H-500 ), 8.03 (2H, d, J ¼ 6.6 Hz, H-200 , H-600 ), 8.15 (1H, d, J ¼ 7.2 Hz, H-4), 10.53 (1H, s, SO2-NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm):43.72 (CH-NH), 125.82 (C-4 pyridazinone), 138.82 (C¼O uriedo group), 145.70 (C-5 pyridazinone), 151.31 (C¼O pyridazinone), 156.10 (C¼N pyridazinone). ESI-MS (m/z): 502 [M+], 503 [M + 1], 501 [M-1], 500 [M-2]. CHNS Analysis for C27H26N4O4S Found (Calculated): C: 63.72 (63.73), H: 4.2 (4.1), N: 12.02 (12.03), O: 14.05 (14.06), S: 6.07 (6.08). 3-Isopropyl-1-{4-[6-oxo-3–(4- propylphenyl) pyridazin-1-yl] benzenesulphonyl} urea (VII) Yellow crystals, yield ¼ 47%, m.p. 185–186  C, Rf ¼ 0.60 (TEF). IR  max (KBr, in cm 1): 3340, 3071 and 2975 (NH-CO-NH), 1700 and 1510 (C¼O) of urea, 1589 (C¼N), 1337 and 1121 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.90 (3H, t, PhCH2CH2CH3), 1.001 (6H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 1.57–1.65 (2H, m, Ph-CH2CH2CH3), 2.61 (2H, t, PhCH2CH2CH3), 3.60–3.66 (1H, m, -NH-CH-(CH3)2), 5.48 (1H,

J Enzyme Inhib Med Chem, Early Online: 1–13

d, J ¼ 7.8 Hz, -NH-CH-(CH3)2), 6.35 (1H, brs, SO2-NH-C¼O), 7.22 (1H, d, J ¼ 9.6 Hz, H-5), 7.32 (2H, d, J ¼ 8.1 Hz, H-30 , H50 ), 7.86 (2H, d, J ¼ 7.8 Hz, H-20 , H-60 ), 7.94 (2H, d, J ¼ 8.7 Hz, H-300 , H-500 ), 8.02 (2H, d, J ¼ 8.4 Hz, H-200 , H-600 ), 8.16 (1H, d, J ¼ 9.6 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 42.27 (CH-NH), 124.36 (C-4 pyridazinone), 137.85 (C¼O uriedo group), 146.19 (C-5 pyridazinone), 150.89 (C¼O pyridazinone), 157.12 (C¼N pyridazinone). ESI-MS (m/z):454 [M+], 455 [M + 1], 453 [M-1], 452 [M-2]. CHNS Analysis for C23H26N4O4S Found (Calculated): C: 60.52 (60.53), H: 5.78 (5.77), N: 12.43 (12.45), O: 14.18 (14.17), S: 7.15 (7.16). 1-{4-[3–(4-Ethoxyphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-3-isopropylurea (VIII) Yellow crystals, yield ¼ 50%, m.p. 148–149  C, Rf ¼ 0.62 (TEF). IR  max (KBr, in cm 1): 3317, 3090 and 2981 (NH-CO-NH), 1718 and 1520 (C¼O) of urea, 1585 (C¼N), 1331 and 1142 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 1.007 (6H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 1.34 (3H, t, Ph-O-CH2-CH3), 3.61– 3.67 (1H, m, -NH-CH-(CH3)2), 4.09 (2H, q, Ph-O-CH2-CH3), 5.40 (1H, brs, -NH-CH-(CH3)2), 7.03 (2H, d, J ¼ 8.7 Hz, H-30 , H50 ), 7.15 (1H, d, J ¼ 11.1 Hz, H-5), 7.85–7.97 (6H, m, H-200 , H600 , H-300 , H-500 , H-20 , H-60 ), 8.02 (1H, d, J ¼ 8.7 Hz, H-4), 8.27 (1H, s, SO2-NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 42.22 (CH-NH), 126.11 (C-4 pyridazinone), 136.87 (C¼O uriedo group), 146.13 (C-5 pyridazinone), 153.15 (C¼O pyridazinone), 157.12 (C¼N pyridazinone). ESI-MS (m/z): 456 [M+], 457 [M + 1], 455 [M-1], 454 [M-2]. CHNS Analysis for C22H24N4O5S Found (Calculated): C: 58.68 (58.67), H: 4.9 (5.01), N: 12.1 (12.09), O: 17.32 (17.31), S: 7.02 (7.01). 3-Isopropyl-1–(4-{6-oxo-3-[4–(2-phenylethyl) phenyl]pyridazin-1-yl}benzenesulphonyl) urea (IX) White crystals, yield ¼ 51%, m.p. 190–191  C, Rf ¼ 0.62 (TEF). IR  max (KBr, in cm1): 3321, 3080 and 2983 (NH-CO-NH), 1729 and 1522 (C¼O) of urea, 1582 (C¼N), 1325 and 1144 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.98 (6H, d, J ¼ 6.6 Hz, -NH-CH-(CH3)2), 2.92 (4H, s, Ph-CH2-CH2-Ph), 3.50–3.59 (1H, m, -NH-CH-(CH3)2), 7.16–7.26 (6H, m, H-5, H-2 000 , H-3 000 , H-4 000 , H-5 000 , H-6 000 ), 7.34 (2H, d, J ¼ 7.2 Hz, H-30 , H-50 ), 7.72–8.13 (7H, m, H-4, H-2 00 , H-6 00 , H-3 00 , H-5 00 , H-20 , H60 ), 8.30 (1H, s, SO2-NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 45.10 (CH-NH), 125.55 (C-4 pyridazinone), 137.67 (C¼O uriedo group), 144.29 (C-5 pyridazinone), 152.19 (C¼O pyridazinone), 155.81 (C¼N pyridazinone).). ESI-MS (m/z): 516 [M+], 517 [M + 1], 515 [M-1], 514 [M-2]. CHNS Analysis for C28H28N4O4S Found (Calculated): C: 65.09 (65.1), H: 5.46 (5.44), N: 10.83 (10.84), O: 12.45 (12.46), S: 6.20 (6.22). 3-Isopropyl-1-{4-[6-oxo-3–(4-phenoxyphenyl) pyridazin-1-yl]benzenesulphonyl}urea (X) White crystals, yield ¼ 53%, m.p. 127–128  C, Rf ¼ 0.61 (TEF). IR  max (KBr, in cm 1): 3336, 3061 and 2981 (NH-CO-NH), 1732 and 1530 (C¼O) of urea, 1591 (C¼N), 1345 and 1165 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.97 (6H, d, J ¼ 6.9 Hz, -NH-CH-(CH3)2), 3.03–3.64 (1H, m, -NH-CH(CH3)2), 5.48 (1H, brs, -NH-CH-(CH3)2), 5.83 (1H, brs, SO2NH-C¼O), 7.07–8.16 (15H, m, H-20 , H-60 , H-30 , H-50 , H-300 , H-5 00 , H-2 00 , H-6 00 , H-2 000 , H-3 000 , H-4 000 , H-5 000 , H-6 000 , H-4, H-5), 8.30 (1H, s, SO2-NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 42.72 (CH-NH), 125.81 (C-4 pyridazinone), 137.74 (C¼O uriedo group), 144.67 (C-5 pyridazinone), 152.21 (C¼O pyridazinone), 155.81 (C¼N pyridazinone). ESI-MS (m/z): 504 [M+], 505 [M + 1], 503 [M-1], 502 [M-2]. CHNS Analysis for

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives

DOI: 10.3109/14756366.2016.1142986

C26H24N4O5S Found (Calculated): C: 61.9 (61.89), H: 4.78 (4.79), N: 11.11 (11.12), O: 15.85 (15.84), S: 6.36 (6.37).

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1-{4-[3–(4-Cyclohexylphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-3-isopropylurea (XI) Yellow crystals, yield ¼ 60%, m.p. 188–189  C, Rf ¼ 0.68 (TEF). IR  max (KBr, in cm 1): 3329, 3071 and 2977 (NH-CONH), 1740 and 1540 (C¼O) of urea, 1605 (C¼N), 1350 and 1168 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 1.06 (6H, d, J ¼ 6.6 Hz, -NH-CH-(CH3)2), 1.22–1.97 (11H, m, cyclohexyl ring), 3.62–3.73 (1H, m, -NH-CH-(CH3)2), 5.56 (1H, d, J ¼ 7.5 Hz, -NH-CH-(CH3)2), 6.28 (1H, brs, SO2-NH-C¼O), 7.27 (1H, d, J ¼ 9.9 Hz, H-5), 7.41 (2H, d, J ¼ 8.1 Hz, H-30 , H-50 ), 7.90–8.01 (4H, m, H-300 , H-5 00 , H-20 , H-60 ), 8.04 (2H, d, J ¼ 8.7 Hz, H-2 00 , H-6 00 ), 8.21 (1H, d, J ¼ 9.6 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 45.31 (CH-NH), 124.93 (C-4 pyridazinone), 138.20 (C¼O uriedo group), 145.32 (C-5 pyridazinone), 153.10 (C¼O pyridazinone), 154.92 (C¼N pyridazinone). ESI-MS (m/z): 494 [M+], 495 [M + 1], 493 [M-1], 492 [M2]. CHNS Analysis for C26H30N4O4S Found (Calculated): C: 63.17 (63.19), H: 6.25 (6.24), N: 11.3 (11.29), O: 12.87 (12.86), S: 6.45 (6.44). 1-{4-[3–(4-Bromophenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-3-isopropylurea (XII) Dark yellow crystals, yield ¼ 43%, m.p. 168–169  C, Rf ¼ 0.70 (TEF). IR  max (KBr, in cm 1): 3341, 3102 and 2988 (NHCO-NH), 1743 and 1538 (C¼O) of urea, 1610 (C¼N), 1341 and 1149 (SO2N); 1H NMR (300 MHz, DMSO-d6, d): 1.16 (6H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 4.12–4.14 (1H, m, -NHCH-(CH3)2), 6.006 (1H, brs, -NH-CH-(CH3)2), 7.20–8.16 (11H, m, H-20 , H-30 , H-50 , H-60 , H-200 , H-300 , H-500 , H-600 , H-4, H-5, SO2-NH C¼O), 13C NMR (75 MHz, DMSO-d6, d, ppm): 44.18 (CH-NH), 125.62 (C-4 pyridazinone), 136.71 (C¼O uriedo group), 145.15 (C-5 pyridazinone), 152.24 (C¼O pyridazinone) 154.31 (C¼N pyridazinone). ESI-MS (m/z): 492 [M + 2], 491 [M + 1], 490 [M+], 489 [M-1]. CHNS Analysis for C20H19BrN4O4S Found (Calculated): C: 49.21 (49.19), H: 3.4 (3.38), Br: 16.17 (16.18), N: 11.45(11.44), O: 13.3(13.29), S: 6.54(6.55). 1-{4-[3–(4-Iodophenyl)-6-oxopyridazin-1-yl] benzenesulfonyl}-3-isopropylurea (XIII) Yellow crystals, yield ¼ 41%, m.p. 171–172  C, Rf ¼ 0.66 (TEF). IR  max (KBr, in cm 1): 3307, 3175 and 2991 (NH-CO-NH), 1750 and 1541 (C¼O) of urea, 1613 (C¼N), 1345 and 1153 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 1.04 (6H, d, J ¼ 7.2 Hz, -NH-CH-(CH3)2), 3.64–3.72 (1H, m, -NH-CH(CH3)2), 5.56 (1H, d, J ¼ 7.5 Hz, -NH-CH-(CH3)2), 6.01 (1H, s, SO2-NH-C¼O), 7.27 (1H, d, J ¼ 9.3 Hz, H-5), 7.59 (2H, d, J ¼ 19.8 Hz, H-20 , H-60 ), 7.81 (2H, d, J ¼ 7.8 Hz, H-30 , H-50 ), 7.91–8.01 (4H, m, H-200 , H-300 , H-500 , H-600 ), 8.22 (1H, d, J ¼ 5.4 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 45.11 (CHNH), 126.31 (C-4 pyridazinone), 135.13 (C¼O uriedo group), 146.22 (C-5 pyridazinone), 153.10 (C¼O pyridazinone), 156.10 (C¼N pyridazinone). ESI-MS (m/z): 538 [M+], 539 [M + 1], 537 [M-1], 536 [M-2]. CHNS Analysis for C20H19IN4O4S Found (Calculated): C: 44.73 (44.71), H: 3.45 (3.47), I: 23.75 (23.74), N: 10.43 (10.44), O: 11.78 (11.77), S: 5.88 (5.87). 1-{4-[3–(4-Hexylphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-3-isopropylurea (XIV) 

Yellow crystals, yield ¼ 42%, m.p. 174–175 C, Rf ¼ 0.63 (TEF). IR  max (KBr, in cm1): 3319, 3091 and 2981 (NH-CO-NH), 1738

5

and 1529 (C¼O) of urea, 1602 (C¼N), 1336 and 1149 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.81 (3H, t, -Ph-(CH2)5-CH3), 1.07 (6H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 1.26 (6H, s, -Ph-CH2CH2-(CH2)3-CH3), 1.55 (2H, q, -Ph-CH2-CH2-(CH2)3-CH3), 2.57 (2H, t, -Ph-CH2-(CH2)4-CH3), 3.71–3.82 (1H, m, -NH-CH(CH3)2), 4.27 (1H, d, J ¼ 6.3 Hz, -NH-CH-(CH3)2), 6.19 (1H, d, J ¼ 9.6 Hz, SO2-NH-C¼O), 7.05 (1H, d, J ¼ 9.6 Hz, H-5), 7.20 (2H, d, J ¼ 7.8 Hz, H-30 , H-50 ) 7.63–7.69 (3H, m, H-20 , H-60 , H-40 ), 7.89 (2H, d, J ¼ 8.4 Hz, H-300 , H-500 ), 8.008 (2H, d, J ¼ 8.1 Hz, H200 , H-600 ). 13C NMR (75 MHz, DMSO-d6, d, ppm): 42.78 (CHNH), 125.42 (C-4 pyridazinone), 135.81 (C¼O uriedo group), 144.85 (C-5 pyridazinone), 153.14 (C¼O pyridazinone), 155.41 (C¼N pyridazinone). ESI-MS (m/z): 496 [M+], 497 [M + 1], 495 [M-1], 494 [M-2]. CHNS Analysis for C26H32N4O4S Found (Calculated): C: 62.76 (62.77), H: 6.52 (6.53), N: 11.31 (11.3), O: 12.92 (12.91), S: 6.51 (6.52). 3-Isopropyl-1-{4-[3–(4-isopropylphenyl)-6-oxopyridazin-1yl]benzenesulphonyl}urea (XV) Light yellow crystals, yield ¼ 50%, m.p. 157–158  C, Rf ¼ 0.65 (TEF). IR  max (KBr, in cm 1): 3362, 3055 and 2975 (NH-CONH), 1725 and 1521 (C¼O) of urea, 1597 (C¼N), 1340 and 1151 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 1.01 (12H, d, J ¼ 6.3 Hz, -Ph-CH-(CH3)2, -NH-CH-(CH3)2), 2.96 (6H, d, J ¼ 6.9 Hz, Ph-CH-(CH3)2), 2.97 (1H, h, Ph-CH-(CH3)2), 3.61–3.68 (1H, m, -NH-CH-(CH3)2), 5.43 (1H, s, -NH-CH-(CH3)2), 7.17 (1H, d, J ¼ 7.8 Hz, H-5), 7.37 (2H, d, J ¼ 7.8 Hz, H-30 , H-50 ), 7.75 (2H, d, J ¼ 8.1 Hz, H-20 , H-60 ), 7.84–7.98 (4H, m, H-200 , H600 , H-300 , H-500 ), 8.10 (1H, d, J ¼ 7.2 Hz, H-4), 8.20 (1H, brs, SO2NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 42.95 (CHNH), 125.54 (C-4 pyridazinone), 136.72 (C¼O uriedo group), 145.45 (C-5 pyridazinone), 152.23 (C¼O pyridazinone), 156.12 (C¼N pyridazinone). ESI-MS (m/z): 454 [M+], 455 [M + 1], 453 [M-1], 452 [M-2]. CHNS Analysis for C23H26N4O4S Found (Calculated): C: 60.6 (60.59), H: 5.7 (5.71), N: 12.39 (12.41), O: 14.25 (14.26), S: 7.08 (7.1). 3-{4-[3–(2,3-Dihydro-1H-inden-5-yl)-6-oxopyridazin-1yl]benzenesulphonyl}-1–(4-methylcyclohexyl) urea (XVI) White crystals, yield ¼ 65%, m.p. 225–226  C, Rf ¼ 0.68 (TEF). IR  max (KBr, in cm  1): 3331, 3028 and 2907 (NH-CO-NH), 1718 and 1531 (C¼O) of urea, 1609 (C¼N), 1329 and 1139 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.90 (3H, d, J ¼ 6.3 Hz, -cyclohexyl-CH3), 1.006–1.92 (9H, m, cyclohexyl ring protons), 2.08–2.13 (2H, m, H-3000 ), 2.97 (4H, d, J ¼ 5.1 Hz, H-2000 , H-4000 ), 3.20 (1H, m, proton at C-1 of cyclohexyl), 5.50 (1H, brs, -NH-cyclohexyl ring), 7.23 (1H, d, J ¼ 9.9 Hz, H-5), 7.40 (1H, d, J ¼ 7.8 Hz, H-50 ), 7.74 (1H, d, J ¼ 8.1 Hz, H-60 ), 7.83 (1H, s, H-20 ), 7.95 (2H, d, J ¼ 8.7 Hz, H-300 , H-500 ), 8.02 (2H, d, J ¼ 8.4 Hz, H-200 , H-600 ), 8.17 (1H, d, J ¼ 9.6 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 48.75 (CH-NH), 125.51 (C-4 pyridazinone), 145.42 (C-5 pyridazinone), 152.17 (C¼O pyridazinone), 155.32 (C¼N pyridazinone), 157.60 (C¼O uriedo group). ESI-MS (m/z): 506 [M+], 507 [M + 1], 505 [M-1], 503 [M-2]. CHNS Analysis for C27H30N4O4S Found (Calculated): C: 65.91 (65.89), H: 5.85 (5.84), N: 11.9 (11.91), O: 10.88 (10.89), S: 5.54 (5.55). 1–(4-Methylcyclohexyl)-3–(4-{3-[4–(2-methylpropyl) phenyl]-6-oxopyridazin-1-yl} benzenesulphonyl) urea (XVII) White crystal, yield ¼ 57%, m.p. 251–252  C, Rf ¼ 0.63 (TEF). IR  max (KBr, in cm 1): 3357, 3021 and 2913 (NH-CO-NH), 1713 and 1508 (C¼O) of urea, 1597 (C¼N), 1331 and 1142 (SO2N). 1H

6

R. Yaseen et al.

NMR (300 MHz, DMSO-d6, d): 0.89–0.98 (9H, m, cyclohexylCH3, Ph-CH2-CH-(CH3)2), 1.05–1.97 (9H, m, cyclohexyl ring), 3.26 (1H, m, proton at C-1 of cyclohexyl), 5.50 (1H, d, J ¼ 5.4 Hz, -NH-cyclohexyl ring), 7.25 (1H, d, J ¼ 9.9 Hz, H-5), 7.35 (2H, d, J ¼ 7.5 Hz, H-30 , H-50 ), 7.90 (2H, d, J ¼ 6.9 Hz, H-20 , H-60 ), 7.96 (2H, d, J ¼ 7.8 Hz, H-300 , H-500 ), 8.02 (2H, d, J ¼ 8.4 Hz, H-200 , H600 ), 8.022 (1H, d, J ¼ 9.6 Hz, H-4), 8.34 (1H, s, SO2-NH-C¼O). 13 C NMR (75 MHz, DMSO-d6, d, ppm): 50.13 (CH-NH), 126.74 (C-4 pyridazinone), 145.35 (C-5 pyridazinone), 152.20 (C¼O pyridazinone), 155.44 (C¼N pyridazinone), 158.93 (C¼O uriedo group). ESI-MS (m/z): 522 [M+], 523 [M + 1], 521 [M-1], 520 [M-2]. CHNS Analysis for C28H34N4O4S Found (Calculated): C: 64.43 (64.41), H: 6.5 (6.49), N: 10.82 (10.81), O: 12.15 (12.17), S: 6.10 (6.12).

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3-{4-[3–(3,4-Difluorophenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl) urea (XVIII) Light yellow crystals, yield ¼ 61%, m.p. 212–213  C, Rf ¼ 0.62 (TEF). IR  max (KBr, in cm 1): 3341, 3027 and 2935 (NH-CONH), 1690 and 1510 (C¼O) of urea, 1597 (C¼N), 1329 and 1147 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.90 (3H, d, J ¼ 6.3 Hz, -cyclohexyl-CH3), 1.008–1.89 (9H, m, cyclohexyl ring protons), 3.31 (1H, m, proton at C-1 of cyclohexyl), 5.54 (1H, d, J ¼ 7.5 Hz, -NH-cyclohexyl ring),): 7.26–8.28 (10H, m, H-30 , H-50 , H-60 , H-4, H-5, H-200 , H-600 , H-300 , H-500 , SO2-NHC¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 49.10 (CH-NH), 124.66 (C-4 pyridazinone), 144.73 (C-5 pyridazinone), 153.11 (C¼O pyridazinone), 156.41 (C¼N pyridazinone), 156.44 (C¼O uriedo group).). ESI-MS (m/z): 502 [M+], 503 [M + 1], 501 [M-1], 500 [M-2]. CHNS Analysis for C20H18F2N4O4S Found (Calculated): C: 57.33 (57.35), H: 4.91 (4.89), F: 7.71 (7.73), N: 11.22 (11.21), O: 12.52 (12.54), S: 6.35 (6.37). 3-{4-[3–(4-Fluorophenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4 methylcyclohexyl) urea (XIX) Yellow crystals, yield ¼ 50%, m.p. 188–189  C, Rf ¼ 0.64 (TEF). IR  max (KBr, in cm 1): 3332, 3059 and 2981 (NHCO-NH), 1715 and 1510 (C¼O) of urea, 1603 (C¼N), 1344 and 1162 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 091 (3H, d, J ¼ 6.6 Hz, -cyclohexyl- CH3), 0.95–2.15 (9H, m, cyclohexyl ring), 3.22 (1H, m, proton at C-1 of cyclohexyl), 7.30 (1H, d, J ¼ 9.6 Hz, H-5), 7.42 (2H, d, J ¼ 8.4 Hz, H-20 , H-60 ), 7.97–8.07 (6H, m, H-30 , H-50 , H-200 , H-600 , H-300 , H-500 ), 8.25 (1H, d, J ¼ 9.9 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 48.66 (CH-NH), 125.56 (C-4 pyridazinone), 145.63 (C-5 pyridazinone), 154.22 (C¼O pyridazinone), 155.74 (C¼O uriedo group), 156.32 (C¼N pyridazinone). ESI (m/z): 484 [M+], 485 [M + 1], 483 [M-1], 482 [M-2]. CHNS Analysis for C24H25FN4O4S Found (Calculated): C: 59.47 (59.45), H: 5.28 (5.30), F: 3.88 (3.90), N: 11.62 (11.63), O: 13.21 (13.20), S: 6.58 (6.57). 1–(4-Methylcyclohexyl)-3-{4-[6-oxo-3–(5,6,7,8-tetrahydronaphthalen-2-yl) pyridazin-1-yl] benzenesulphonyl} urea (XX) White crystals, yield ¼ 45%, m.p. 240–241  C, Rf ¼ 0.67 (TEF). IR  max (KBr, in cm  1): 3362, 3078 and 3003 (NH-CO-NH), 1729 and 1525 (C¼O) of urea, 1621 (C¼N), 1350 and 1188 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.89 (3H, d, J ¼ 6.3 Hz, cyclohexyl-CH3), 1.006–2.11 (9H, m, cyclohexyl ring), 1.79 (4H, s, H-3000 , H-4000 ), 2.98 (4H, s, H-2000 , H-5000 ), 3.26 (1H, m, proton at C-1of cyclohexyl), 5.57 (1H, brs, -NHcyclohexyl ring), 7.24 (2H, m, H-5, H-50 ), 7.67–7.74 (2H, m, H-20 , H-60 ), 7.79–7.99 (4H, m, H-200 , H-600 , H-300 , H-500 ), 8.17–8.34 (2H,

J Enzyme Inhib Med Chem, Early Online: 1–13

m, H-4, SO2-NH-C¼O), 13C NMR (75 MHz, DMSO-d6, d, ppm): 47.75 (CH-NH), 125.66 (C-4 pyridazinone), 145.77 (C-5 pyridazinone), 153.66 (C¼O pyridazinone), 155.81 (C¼O uriedo group), 156.32 (C¼N pyridazinone). ESI-MS (m/z):520 [M+], 521 [M + 1], 519 [M-1], 518 [M-2]. CHNS Analysis for C28H32N4O4S Found (Calculated): C: 64.38 (64.40), H: 6.22 (6.20), N: 10.55 (10.56), O: 12.67 (12.68), S: 6.25 (6.24). 3-{4-[3–(4-Benzylphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl) urea (XXI) White crystals, yield ¼ 68%, m.p. 239–240  C, Rf ¼ 0.7 (TEF). IR  max (KBr, in cm 1): 3347, 3053 and 3007 (NH-CO-NH), 1710 and 1529 (C¼O) of urea, 1608 (C¼N), 1361 and 1170 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.84 (3H, d, J ¼ 6.3 Hz, cyclohexyl-CH3), 0.94–1.90 (9H, m, cyclohexyl ring), 3.51 (1H, m, proton at C-1 of cyclohexyl), 3.99 (2H, s, Ph-CH2-Ph),): 5.48 (1H, d, J ¼ 7.8 Hz, -NH-cyclohexyl ring), 5.71 (1H, brs, SO2-NH-C¼O), 7.16–7.38 (8H, m, H-5, H-2000 , H3000 , H-4000 , H-5000 , H-6000 , H-30 , H-50 ), 7.63–8.09 (6H, m, H-200 , H600 , H-300 , H-500 , H-20 , H-60 ), 8.12 (1H, d, J ¼ 7.2 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 47.80 (CH-NH), 125.44 (C-4 pyridazinone), 145.22 (C-5 pyridazinone), 155.33 (C¼O uriedo group), 154.21 (C¼O pyridazinone), 155.11 (C¼N pyridazinone). ESI-MS (m/z): 556 [M+], 557 [M + 1], 555 [M-1], 554 [M-2]. CHNS Analysis for C31H32N4O4S Found (Calculated): C: 66.68 (66.69), H: 5.99 (5.97), N: 10.25 (10.26), O: 11.32 (11.31), S: 5.80 (5.79). 1–(4-Methylcyclohexyl)-3-{4-[6-oxo-3–(4-propylphenyl)pyridazin-1-yl] benzenesulphonyl} urea (XXII) Light yellow crystals, yield ¼ 57%, m.p. 246–247  C, Rf ¼ 0.66 (TEF). IR  max (KBr, in cm 1): 3335, 3063 and 2968 (NH-CONH), 1696 and 1507 (C¼O) of urea, 1581 (C¼N), 1332 and 1125 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.825 (3H, d, J ¼ 5.4 Hz, cyclohexyl-CH3), 1.03–1.90 (9H, m, cyclohexyl ring), 3.20 (1H, m, proton at C-1 of cyclohexyl): 5.44 (1H, d, J ¼ 8.1 Hz, -NH-cyclohexyl), 5.70 (1H, brs, SO2-NH-C¼O), 7.16–8.17 (10H, m, H-5, H-30 , H-50 , H-20 , H-60 , H-300 , H-500 , H-200 , H-600 , H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 50.10 (CH-NH), 125.44 (C-4 pyridazinone), 145.22 (C-5 pyridazinone), 154.18 (C¼O pyridazinone), 155.12 (C¼N pyridazinone), 155.33 (C¼O uriedo group). ESI-MS (m/z): 508 [M+], 509 [M + 1], 507 [M-1], 506 [M-2]. CHNS Analysis for C27H32N4O4S Found (Calculated): C: 63.36 (63.37), H: 6.74 (6.73), N: 10.97 (10.96), O: 12.58 (12.59), S: 6.35 (6.37). 3-{4-[3–(4-Ethoxyphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl) urea (XXIII) Yellow crystals, yield ¼ 49%, m.p. 241–242  C, Rf ¼ 0.71 (TEF). IR  max (KBr, in cm 1): 3320, 3092 and 2986 (NHCO-NH), 1721 and 1530 (C¼O) of urea, 1590 (C¼N), 1333 and 1146 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.96 (3H, d, J ¼ 8.7 Hz, cyclohexyl-CH3), 1.002–1.24 (5H, m, cyclohexyl ring), 1.30 (3H, t, Ph-O-CH2-CH3), 1.37–1.73 (4H, m, cyclohexyl ring), 3.18 (1H, m, proton at C-1 of cyclohexyl), 4.09 (2H, q, Ph-O-CH2-CH3), 6.38 (1H, d, J ¼ 5.1 Hz, -NHcyclohexyl), 7.04 (2H, d, J ¼ 6.6 Hz, H-30 , H-50 ), 7.21 (1H, d, J ¼ 7.2 Hz, H-5), 7.90 (2H, d, J ¼ 6.6 Hz, H-20 , H-60 ), 7.96 (2H, d, J ¼ 6.6 Hz, H-300 , H-500 ), 8.03 (2H, d, J ¼ 6.6 Hz, H-200 , H-600 ), 8.16 (1H, d, J ¼ 7.5 Hz, H-4), 10.51 (1H, s, SO2-NHC¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 46.91 (CHNH), 125.33 (C-4 pyridazinone), 145.80 (C-5 pyridazinone), 153.42 (C¼O pyridazinone), 155.35 (C¼N pyridazinone),

DOI: 10.3109/14756366.2016.1142986

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives

156.81 (C¼O uriedo group). ESI-MS (m/z):510 [M+], 511 [M + 1], 509 [M-1], 508 [M-2]. CHNS Analysis for C26H30N4O5S Found (Calculated): C: 61.35 (61.33), H: 5.80 (5.81), N: 10.86 (10.87), O: 15.75 (15.77), S: 6.25 (6.27).

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1–(4-Methylcyclohexyl)-3–(4-{6-oxo-3-[4–(2-phenylethyl)phenyl]pyridazin-1-yl} benzenesulphonyl) urea (XXIV) White crystals, yield ¼ 63%, m.p. 287–288  C, Rf ¼ 0.61 (TEF). IR  max (KBr, in cm 1): 3323, 3084 and 2987 (NHCO-NH), 1733 and 1528 (C¼O) of urea, 1589 (C¼N), 1335 and 1151 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.84 (3H, d, J ¼ 6 Hz, cyclohexyl-CH3), 0.89–1.24 (9H, m, cyclohexyl ring), 2.92 (4H, s, Ph-CH2-CH2-Ph), 3.12 (1H, m, proton at C-1 of cyclohexyl), 7.15–8.16 (17H, m, H-20 , H-30 , H-50 , H-60 , H-200 , H-300 , H-500 , H-600 , H-2000 , H-3000 , H-4000 , H-5000 , H-6000 , H-4, H-5, SO2-NH-C¼O, -NH-cyclohexyl ring), 0.84 (3H, d, J ¼ 6 Hz, cyclohexyl-CH3). 13C NMR (75 MHz, DMSO-d6, d, ppm): 44.88 (CH-NH), 125.66 (C-4 pyridazinone), 145.17 (C-5 pyridazinone), 153.17 (C¼O pyridazinone), 155.22 (C¼N pyridazinone), 156.55 (C¼O uriedo group). ESIMS (m/z): 570 [M+], 571 [M + 1], 569 [M-1], 568 [M-2]. CHNS Analysis for C32H34N4O4S Found (Calculated): C: 67.41 (67.43), H: 5.81 (5.80), N: 9.81 (9.82), O: 11.30 (11.29), S: 5.70 (5.71). 1–(4-Methylcyclohexyl)-3-{4-[6-oxo-3–(4-phenoxyphenyl)pyridazin-1-yl]benzenesulphonyl}urea (XXV) White crystals, yield ¼ 51%, m.p. 236–237  C, Rf ¼ 0.72 (TEF). IR  max (KBr, in cm 1): 3340, 3062 and 2989 (NHCO-NH), 1738 and 1545 (C¼O) of urea, 1597 (C¼N), 1358 and 1167 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.84 (1H, d, J ¼ 6.3 Hz, cyclohexyl-CH3), 1.03–1.90 (9H, m, cyclohexyl ring), 3.27 (1H, m, proton at C-1 of cyclohexyl), 5.44 (1H, brs, -NH-cyclohexyl ring), 5.50 (1H, brs, SO2-NHC¼O), 7.07–7.45 (10H, m, H-20 , H-30 , H-50 , H-60 , H-2000 , H-3000 , H-4000 , H-5000 , H-6000 , H-5), 7.88 (2H, d, J ¼ 8.1 Hz, H-300 , H-500 ), 7.95 (2H, d, J ¼ 8.4 Hz, H-200 , H-600 ), 8.11 (1H, d, J ¼ 9.3 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 46.20 (CH-NH), 126.12 (C-4 pyridazinone), 146.40 (C-5 pyridazinone), 155.11 (C¼O pyridazinone), 155.16 (C¼N pyridazinone), 155.52 (C¼O uriedo group). ESI-MS (m/z): 558 [M+], 559 [M + 1], 557 [M-1], 556 [M-2]. CHNS Analysis for C30H30N4O5S Found (Calculated): C: 64.55 (64.56), H: 5.26 (5.28), N: 10.15 (10.13), O: 14.37 (14.36), S: 5.75 (5.74). 3-{4-[3–(4-Cyclohexylphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl)urea (XXVI) Yellow crystals, yield ¼ 60%, m.p. 280–281  C, Rf ¼ 0.73 (TEF). IR  max (KBr, in cm 1): 3322, 3065 and 2971 (NH-CO-NH), 1736 and 1528 (C¼O) of urea, 1601 (C¼N), 1347 and 1161 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.90 (3H, d, J ¼ 6.3 Hz, cyclohexyl-CH3), 0.96–2.08 (20H, m, cyclohexyl rings), 3.23 (1H, m, proton at C-1 of cyclohexyl),): 5.52 (1H, d, J ¼ 8.1 Hz, -NH-cyclohexyl ring), 6.13 (1H, brs, SO2-NH-C¼O), 7.25 (1H, d, J ¼ 9.6 Hz, H-5), 7.40 (2H, d, J ¼ 8.4 Hz, H-30 , H50 ), 7.90 (2H, d, J ¼ 7.8 Hz, H-300 , H-500 ), 8.01 (2H, d, J ¼ 8.1 Hz, H-20 , H-60 ), 8.19 (1H, d, J ¼ 9.6 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 47.11 (CH-NH), 125.32 (C-4 pyridazinone), 145.43 (C-5 pyridazinone), 156.12 (C¼O uriedo group), 156.20 (C¼N pyridazinone), 156.71 (C¼O pyridazinone). ESIMS (m/z): 548 [M+], 549 [M + 1], 547 [M-1], 546 [M-2]. CHNS Analysis for C30H36N4O4S Found (Calculated): C: 65.81 (65.83), H: 6.53 (6.54), N: 10.30 (10.29), O: 11.59 (11.6), S: 5.80 (5.81).

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3-{4-[3–(4-Bromophenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl)urea (XXVII) Light yellow crystals, yield ¼ 55%, m.p. 231–232  C, Rf ¼ 0.62 (TEF). IR  max (KBr, in cm1): 3338, 3100 and 2982 (NH-CO-NH), 1740 and 1533 (C¼O) of urea, 1608 (C¼N), 1339 and 1142 (SO2N). 1H NMR (300 MHz, DMSOd6, d): 1.17 (3H, d, J ¼ 8.1 Hz, cyclohexyl-CH3), 1.22–1.92 (9H, m, cyclohexyl ring), 3.21 (1H, m, proton at C-1 of cyclohexyl), 6.50 (1H, brs, -NH-cyclohexyl ring), 7.45 (1H, d, J ¼ 7.5 Hz, H-5), 7.91 (2H, d, J ¼ 6.3 Hz, H-20 , H-60 ), 8.12 (2H, d, J ¼ 6.3 Hz, H-30 , H-50 ), 8.15 (2H, d, J ¼ 6.6 Hz, H-300 , H-500 ), 8.23 (2H, d, J ¼ 6.3 Hz, H-200 , H-600 ), 8.39 (2H, d, J ¼ 6.3 Hz, H-200 , H-600 ), 8.39 (1H, d, J ¼ 7.2 Hz, H-4), 10.72 (1H, s, SO2-NH-C¼O). 13C NMR (75 MHz, DMSO-d6, d, ppm): 49.10 (CH-NH), 125.70 (C-4 pyridazinone), 145.77 (C-5 pyridazinone), 154.35 (C¼O pyridazinone), 155.66 (C¼N pyridazinone), 156.35 (C¼O uriedo group). ESI-MS (m/z):546 [M + 2], 544 [M+], 545 [M + 1]. CHNS Analysis for C24H25BrN4O4S Found (Calculated): C: 52.88 (52.86), H:4.7 (4.71), Br: 14.61 (14.60), N: 10.28 (10.29), O: 11.71 (11.73), S: 5.87 (5.88). 3-{4-[3–(4-Iodophenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl) urea (XXVIII) Yellow crystals, yield ¼ 47%, m.p. 253–2545  C, Rf ¼ 0.63 (TEF). IR  max (KBr, in cm1): 3312, 3182 and 2997 (NHCO-NH), 1752 and 1545 (C¼O) of urea, 1617 (C¼N), 1354 and 1166 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.90 (3H, d, J ¼ 6.3 Hz, cyclohexyl-CH3), 0.96–1.91 (9H, m, cyclohexyl ring), 3.2 (1H, m, proton at C-1 of cyclohexyl), 5.52 (1H, d, J ¼ 7.8 Hz, -NH-cyclohexyl ring), 6.03 (1H, brs, SO2-NH-C¼O), 7.28 (1H, d, J ¼ 6.9 Hz, H-5), 7.62 (2H, d, J ¼ 9.6 Hz, H-20 , H-60 ), 7.80 (2H, d, J ¼ 8.4 Hz, H-30 , H-50 ), 7.87–8.05 (4H, m, H-200 , H-300 , H-500 , H-600 ), 8.23 (1H, d, J ¼ 5.4 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 50.13 (CH-NH), 125.66 (C-4 pyridazinone), 146.55 (C-5 pyridazinone), 154.17 (C¼O pyridazinone), 155.45 (C¼O uriedo group), 156.22 (C¼N pyridazinone). ESI-MS (m/z): 592 [M+], 593 [M + 1], 591 [M-1], 590 [M-2]. CHNS Analysis for C24H25IN4O4S Found (Calculated): C: 48.65 (48.63), H: 4.27 (4.26), I: 21.57 (21.55), N: 9.43 (9.41), O: 10.76 (10.75), S: 5.39 (5.41). 3-{4-[3–(4-Hexylphenyl)-6-oxopyridazin-1-yl] benzenesulphonyl}-1–(4-methylcyclohexyl) urea (XIXX) White crystals, yield ¼ 53%, m.p. 281–282  C, Rf ¼ 0.65 (TEF). IR  max (KBr, in cm 1): 3325, 3101 and 2989 (NHCO-NH), 1744 and 1538 (C¼O) of urea, 1609 (C¼N), 1341 and 1150 (SO2N), 1H NMR (300 MHz, DMSO-d6, d): 0.80 (3H, t, -Ph-(CH2)5-CH3), 0.90 (3H, d, J ¼ 6.3 Hz, cyclohexyl ring -CH3), 0.96–1.33 (9H, m, cyclohexyl ring), 1.33 (6H, s, -Ph-CH2-CH2-(CH2)3-CH3), 1.74 (2H, q, -Ph-CH2-CH2-(CH2)3CH3), 2.68 (2H, t, -Ph-CH2-(CH2)4-CH3), 3.24 (1H, m, proton at C-1 of cyclohexyl), 5.51 (1H, d, J ¼ 7.8 Hz, -NH-cyclohexyl ring), 6.50 (1H, brs, SO2-NH-C¼O), 7.25 (1H, d, J ¼ 9.6 Hz, H-5), 7.37 (2H, d, J ¼ 8.4 Hz, H-30 , H-50 ), 7.88–8.05 (6H, m, H-20 , H-60 , H-300 , H-500 , H-200 , H-600 ), 8.18 (1H, d, J ¼ 9.6 Hz, H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 48.35 (CH-NH), 125.64 (C-4 pyridazinone), 146.22 (C-5 pyridazinone), 155.25 (C¼O uriedo group), 155.30 (C¼N pyridazinone), 156.80 (C¼O pyridazinone). ESI-MS (m/z): 550 [M+], 551 [M + 1], 549 [M-1], 548 [M-2]. CHNS Analysis for C30H38N4O4S Found (Calculated): C: 65.73 (65.75), H: 6.97 (6.96), N: 10.13 (10.11), O: 11.51 (11.50), S: 5.69 (5.71).

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R. Yaseen et al.

J Enzyme Inhib Med Chem, Early Online: 1–13

3-{4-[3–(4-Isopropylphenyl)-6-oxopyridazin-1-yl]benzenesulphonyl}-1–(4-methylcyclohexyl)urea (XXX)

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White crystals, yield ¼ 57%, m.p. 248–249 C, Rf ¼ 0.65 (TEF). IR  max (KBr, in cm 1): 3364, 3056 and 2978 (NH-CONH), 1729 and 1523(C¼O) of urea, 1607 (C¼N), 1343 and 1157 (SO2N). 1H NMR (300 MHz, DMSO-d6, d): 0.79 (3H, d, J ¼ 4.8 Hz, cyclohexyl ring -CH3), 0.86–1.17 (9H, m, cyclohexyl ring), 1.23 (6H, d, J ¼ 6 Hz, Ph-CH-(CH3)2), 2.86 (1H, h, Ph-CH-(CH3)2), 3.19 (1H, m, proton at C-1 of cyclohexyl), 3.20–3.31 (1H, m, -NH-CH-(CH3)2), 4.47 (1H, d, J ¼ 8.1 Hz, -NH-cyclohexyl ring), 7.08 (1H, d, J ¼ 9.9 Hz, H-5), 7.27 (2H, d, J ¼ 8.4 Hz, H-30 , H-50 ), 7.52 (1H, s, SO2-NH-C¼O), 7.75 (2H, d, J ¼ 8.4 Hz, H-20 , H-60 ), 7.86 (2H, d, J ¼ 6.9 Hz, H-300 , H-500 ), 7.93–8.04 (3H, m, H-200 , H-600 , H-4). 13C NMR (75 MHz, DMSO-d6, d, ppm): 47.80 (CH-NH), 125.44 (C-4 pyridazinone), 145.22 (C-5 pyridazinone), 154.21 (C¼O pyridazinone), 155.11 (C¼N pyridazinone), 155.33 (C¼O uriedo group). ESIMS (m/z): 508 [M+], 509[M + 1], 507 [M-1], 506 [M-2].CHNS Analysis for C27H32N4O4S Found (Calculated): C: 63.60 (63.59), H: 6.38 (6.39), N: 11.10 (11.09), O: 12.62 (12.63), S: 6.35 (6.33). Effect of synthesized compounds on oral glucose tolerance in normal rats All the experiments were performed utilizing albino rats of Wistar strain (either sex) weighing 210 ± 10 g which were provided by the Animal House of Department of Pharmacology, State Company for Drug Industries and Medical Appliances, Samarra/Baghdad (1871/SDI) and were housed in the same location under standardized conditions. Animals were fed commercial chaw and had free access to water ad libitum. The experiments were performed in congruence with the instructions for the care and use of laboratory animals, ordained by the State Company for Drug Industries and Medical Appliances SDI. Animals delineated as fasted were bereaved of food for at least 16 h but permitted free access to water. Carboxymethyl cellulose CMC (1%w/v) in distilled water was used as vehicle for dosing in all the experiments. All treatments were given orally using gauge. Fasted rats were divided into groups of six animals each. Animals of group I were fed with the vehicle (CMC 1% w/v in distilled water) in a volume of 10 ml/kg, while animals of group II were given gliclazide 0.05 mM/kg suspended in the vehicle. Animals of the experimental group (I–XXX) were administered the suspension of the test compounds at a dosage of 0.05 mM/kg b.w. A glucose load (3 g/kg) was given to each animal exactly after 30-min post-administration of the respective treatments. Blood samples were collected from retro-orbital plexus just prior to and 60 min after the glucose loading and blood glucose levels were measured with an autoanalyser (Accu Check Active glucose kit)27. Docking Docking studies were implemented utilizing Glide module of the Schrodinger-9 software on the aldose reductase (PDB id: 1EL3, 1USO, 2FZD and 2PDK). Receptor preparation was done using protein preparation wizard with defaults settings. The structures were sketched using maestro graphical user interface (GUI) and were energy minimized/cleaned up by Ligprep module of the same software using OPLS_2005 force field and proper protonation states were assigned with the ionizer subprogram at pH ˚ around cocrystallized ligand was 7.2 ±0.228. A grid space of 20 A set for the docking calculations. Glide XP module was used for final docking studies29.

Preparation of rat lens aldose reductase Crude AR was prepared from rat lens through reported method30. Institutional and national guidelines for the care and use of animals were followed and all experimental procedures involving animals were approved by the IAEC (institutional animal ethical committee) of the National Institute of Nutrition. Lenses were homogenized in nine volumes of 100 mM potassium phosphate buffer, pH 6.2. The homogenate was centrifuged at 15 000  g for 30 min at 4  C and the resulting supernatant was used as the source of ALR2.

Aldose reductase activity assay Aldose reductase (AR) activity was assayed as described by Suryanarayana30. All the experiments were performed in triplicate. The assay mixture in 1 ml contained 50 mM potassium phosphate buffer, pH 6.2, 0.4 M lithium sulphate, 5 mM b-mercaptoethanol, 10 mM DL-glyceraldehyde, 0.1 mM NADPH and enzyme preparation. Appropriate blanks were employed for corrections. The assay mixture was incubated at 37  C and the reaction was initiated by the addition of NADPH at 37  C. The change in the absorbance at 340 nm due to NADPH oxidation was followed in a spectrophotometer.

Enzyme inhibition studies For inhibition studies, a concentrated stock of pyridazinonesubstituted benzenesulphonylurea derivatives (I–XXX) was prepared in DMSO. Aliquots drawn from a working solution were added to the enzyme assay mixture and incubated for 5 min before initiating the reaction by NADPH as described above. The per cent inhibition with test compound was calculated considering the enzyme activity in the absence of inhibitor as 100%. The concentration of each test sample giving 50% inhibition (IC50) was determined by non-linear regression analysis of log concentration of compound versus percentage inhibition.

Results and discussion Synthesis of compounds The synthetic route used to synthesize title compounds (I–XXX) is outlined in Scheme 1. The 4-aryl-pyridazinone-substituted benzenesulphonamides derivatives (2a–o) synthesized through reported method31 were converted to corresponding sulphonyl urea derivatives by refluxing with appropriate isocyanate in dry acetone containing K2CO3. The structure of synthesized pyridazinones-substituted benzenesulphonylurea derivatives (I–XXX) were determined on the basis of elemental analysis and various spectroscopic methods, such as IR, 1H NMR, 13C NMR and MS. Elemental analysis (C, H, N and S) data were within ±0.5% of the theoretical values. All the peaks corresponding to IR, 1H NMR and 13C NMR were observed at expected positions in respective spectra (for details see experimental section). Oral glucose tolerance test in normal rats (OGGT) In the current study, oral hypoglycaemic effects of 30 newly synthesized compounds (I–XXX) were assessed in glucose-fed hyperglycaemic normal rats at the dose of 0.05 mM/kg b.w. The clinically used sulphonyl urea drug gliclazide at the dose 0.05 mM/kg b.w. was used as positive control. Quantitative glucose tolerance of each animal was calculated by area under curve (AUC) method by using prism software. Comparing AUC of experimental and control groups determined the percentage antihyperglycaemic activity. Statistical comparison

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives

DOI: 10.3109/14756366.2016.1142986

9

NHNH2HCl

H

O O Ar

+

O O

a

O

S

Ar

O

O N

NH2

Ar

H

N

OH O

(1a-o)

b

S O

O NH2

(2a-o)

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c

1a, 2a, I, XVI: Ar=Indanyl 1b, 2b, II, XVII: Ar=4-Isobutylphenyl 1c, 2c, III, XVIII: Ar=3,4-Difluorophenyl 1d, 2d, IV, XIX: Ar=4-Fluorolphenyl 1e, 2e, V, XX: Ar=Tetralinyl 1f, 2f, VI, XXI: Ar=4-Benzylphenyl 1g, 2g, VII, XXII: Ar=4-Propyllphenyl 1h, 2h, VIII, XXIII: Ar=4-Ethoxylphenyl 1i, 2i, IX, XXIV: Ar=4-(2-phenylethyl)phenyl 1j, 2j, X, XXV: Ar=4-Phenoxylphenyl 1k, 2k, XI, XXVI: Ar=4-Cyclohexylphenyl 1l, 2l, XII, XXVII: Ar=4-Bromolphenyl 1m, 2m, XIII, XXVIII: Ar=4-Iodolphenyl 1n, 2n, XIV, XXIX: Ar=4-Hexylphenyl 1o, 2o, XV, XXX: Ar= 4-Isopropylphenyl

H

H

5

4

Ar

O N

N 2" 3"

6" 5"

S O

O NH

O NH

I-XV: R= Isopropyl XVI-XXX: R=4-Methylcyclohexyl

R (I-XXX)

Scheme 1. Synthesis of pyridazinone-based benzenesulphonylurea derivatives. Reagents and conditions: (a) maleic anhydride, 1,1,2,2tetrachloroethane, AlCl3; (b) Absolute alcohol, reflux 12–18 h; (c) Appropriate isocyanate, K2CO3, dry acetone, reflux 24–72 h. Table 1. In vivo OGTT results for the compounds (I–XXX).

was made by Dunnett’s test. Samples showing significant inhibition (p50.05) on postprandial hyperglycaemia were considered as active samples. The results are summarized in Table 1. Twenty-three compounds (III–XI, XIV–XVII, XIX–XXIV, XXVI and XXVIII– XXX) out of 30 compounds showed more or comparable area under the curve (AUC) reduction percentage (ranging from 21.9% to 35.5%) as compared to the standard drug gliclazide (22.0%). The compound VIII is the most active compound and exhibited 35.5% AUC reduction. With regard to the SAR, it seems impossible to extract an obvious structure–activity relationship from the data shown in Table 1. Docking Docking studies of 30 synthesized compounds (I to XXX) were performed in order to get better comprehension of the aldose reductase inhibitory potency at molecular level and to shed light on the interactions in the active site of aldose reductase. Docking studies were performed using Glide module of the Schrodinger9.4 software on the Aldose reductase (ALR) receptor (PDB id: 1EL3, 1USO, 2FZD, 2PDK). The most relevant poses were obtained with PDBID: 1EL3. However, the docking studies were performed with PDB ID: 1El3 because this structure is bound with IDD384, which is a sulphonamide derivative and is relevant with our study. The re-docking of reference ligand (IDD384) into active site of aldose reductase enzyme reveals that it occupies the same binding pocket with root mean square deviation (RMSD) of 0.61A which further validates the present docking protocol (Figure 3).

Treatment 0.05 mmol/kg b.w. Control Gliclazide I II III IV V VI VII VIII IX X XI XII XIII XIV XV XVI XVII XVIII XIX XX XXI XXII XXIII XXIV XXV XXVI XXVII XXVIII XXIX XXX

AUC reduction %

Significance

– 22.0 3.6 10.5 26.8 30.5 25.8 30.1 25.5 35.5 32.4 34.9 27.3 20.2 21.7 33.4 25.7 24.3 27.8 15.0 21.9 26.0 22.0 28.6 26.5 31.0 17.8 24.9 19.8 20.5 30.5 30.0

– p50.01 p40.05 p40.05 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01 p50.01

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R. Yaseen et al.

J Enzyme Inhib Med Chem, Early Online: 1–13

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Figure 3. Binding interaction of cocrystallized ligand (IDD384) with ALR catalytic domain.

Figure 4. Compound III binding interaction with ALR catalytic domain (PDBID: 1El3).

Figure 5. Compound V binding interaction with ALR catalytic domain (PDBID: 1El3).

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DOI: 10.3109/14756366.2016.1142986

Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives

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Figure 6. superimposition of compounds V and III with cocrystallized ligand (1dd384) against ALR enzyme (A) with, V with (B) III.

Figure 7. Comparison of binding interaction of inactive X with (A) cocrystallized ligand, (B) with V, (C) with III.

Docking results reveal that the compounds III and V bound tightly in the active site of aldose reductase (ALR2). These compounds (III and V) well occupied in the receptor cavity and forms hydrogen bonds and hydrophobic interactions (Figures 4 and 5). The sulfonamide group of III and V is anchored into the anion-binding site formed by Ala299, Leu300 and Trp111 and

forms hydrogen-bonding with Trp111, which is key residue in binding and catalysis32,33. The 1,2,3,4-tetrahydronaphthalene ring core gets tightly trapped in the hydrophobic pocket formed by Phe122, Leu300, Leu301, Leu124 and Val130. Further docking analysis of compounds V and III with cocrystallized ligand (1DD384) by superimposition; it gives the same interaction

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R. Yaseen et al. Table 2. Aldose inhibitory data. Compounds

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III IV V VI X XII XIII XV XVI XVII XVIII XX XXI XXII XXV XXVII XXIX XXX Quercetin

J Enzyme Inhib Med Chem, Early Online: 1–13

reductase

(AR)

IC50 (mM)* 63 45 34 237 n.a.y 77 n.a. n.a. 119 187 75 n.a. 384 n.a. n.a. 242 n.a. n.a. 41

*IC50 values, represent the concentration required to produce 50% enzyme inhibition. yn.a.: Not active.

pattern of binding with catalytic domain of ALR enzyme. The fact is also validated by Figure 6 where III and V were superimposed on cocrystal ligand. The binding pose of compound X (Figure 7A–C) reveals why it is inactive. It does not fit well in the receptor binding site and does not show hydrogen bonding like III and V. This may be explained on the basis that the cyclohexyl attached to the sulphonamide moiety renders the configuration of molecule. Moreover, all other groups attached to the pyridazinone ring show different poses when compared to the III and V (Figure 7B and C). Therefore, it misses all the important interactions required for ALR inhibition. The fact is also validated by (Figure 7B), where X was superimposed on V and it is clear that compound V has more relaxed conformation that compound X. Aldose reductase inhibition Eighteen synthesized compounds were evaluated in vitro for their ability to inhibit activity of partially purified rat lens aldose reductase (AR). It has been shown that there is an approximately 85% sequence similarity between rat lens and human aldose reductase (ALR2), while the proposed active sites of both enzymes are identical32. The performed assay was based on a spectrometric measurement, which is proven to be a reliable method33, with DL-glyceraldehyde as the substrate and NADPH as the cofactor. Quercetin, a known ARI was used as a positive control. Results are presented in Table 2. Out of the tested 18 compounds, only ten compounds showed aldose reductase activity with IC50 ranging from 34 to 242 mM. Among these derivatives, compound IV (IC50 ¼ 45 mM) and V (IC50 ¼ 34 mM) were found comparable with the known ARI quercetin (IC50 ¼ 41 mM). As regards to the structural activity relationship, no definite SAR could be extracted from Table 2.

Conclusion In the present study, 30 new pyridazinone-substituted benzenesulphonylurea derivatives (I–XXX) were synthesized. The synthesized compounds are well supported by the spectroscopic data and elemental analysis. These compounds were screened for

their antihyperglycaemic activity using in vivo OGTT assay (albino rats of Wistar strain). Eighteen compounds displaying good docking results were screened for their in vitro ability to inhibit rat lens aldose reductase. As a result, two compounds (IV and V) were identified possessing significant dual action (antihyperglycaemic and aldose reductase inhibition) and may be used as lead compounds for developing new drugs.

Declaration of interest The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

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Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives

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Design and synthesis of pyridazinone-substituted benzenesulphonylurea derivatives as anti-hyperglycaemic agents and inhibitors of aldose reductase - an enzyme embroiled in diabetic complications.

Thirty new aryl-pyridazinone-substituted benzenesulphonylurea derivatives (I-XXX) were synthesized and evaluated for their anti-hyperglycaemic activit...
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