Home Synthesis and bioactivity of novel C2-glycosyl triazole derivatives as acetylcholinesterase inhibitors
Article Open Access

Synthesis and bioactivity of novel C2-glycosyl triazole derivatives as acetylcholinesterase inhibitors

  • Long Yin , Lei Wang , Xiu-Jian Liu , Feng-Chang Cheng , Da-Hua Shi , Zhi-Ling Cao and Wei-Wei Liu EMAIL logo
Published/Copyright: June 9, 2017
Download Article (PDF)
Heterocyclic Communications
From the journal Heterocyclic Communications Volume 23 Issue 3

Abstract

New C2-glycosyl triazole derivatives 6a–l were synthesized by cyclization of glycosyl acylthiosemicarbazides 5 in refluxing 3 N sodium hydroxide aqueous solution. Substrates 5 were obtained by the reaction of glycosyl isothiocyanate 3 with various hydrazides. The acetylcholinesterase (AChE) inhibitory activities of compounds 6 were tested by Ellman’s method. Compounds that exhibited over 85% inhibition were subsequently evaluated for the IC50 values. Compound 6f possesses the best acetylcholinesterase-inhibition activity with IC50 of 1.46±0.25 μg/mL.

Keywords: acetylcholinesterase; C2-glycosyl triazole derivatives; synthesis

Introduction

Carbohydrates play an important role in biological and industrial applications [1], [2], [3], [4], [5], [6]. D-Glucosamine is a naturally occurring amino sugar [7], [8] that has been widely used for the prevention and treatment of rheumatoid arthritis and osteoarthritis [9], [10]. It also exhibits a broad variety of bioactivities including anti-inflammatory [11], antioxidant [12], antibacterial [13] and antitumor properties [14]. Modified naturally occurring amino sugars are used for the development of anti-proliferative [15], anti-acetylcholinesterase [16], anticandidal [17] and other active agents [18], [19], [20], [21].

In recent years, triazoles and their fused heterocyclic derivatives have received considerable attention owing to their importance in drug discovery [22], [23], [24]. 1,2,4-Triazoles and their derivatives are commonly utilized heterocyclic pharmacophores, which are an important class of heterocyclic molecules presenting numerous biological activities such as antimicrobial [25], antiproliferative [26], antiviral [27], anti-inflammatory [28] and anticonvulsant [29] activities. Recent studies have shown that many compounds containing the triazole skeleton act as choline esterase inhibitors for the treatment of Alzheimer’s disease [30], [31], [32].

Up to now, researchers have been interested in molecular hybrid-based approaches to find some new compounds of potential biological activities [33], [34], [35]. Based on these findings and our previous work, in an attempt to discover new potent acetylcholinesterase (AChE) inhibitors, we designed and synthesized a series of novel C2-glycosyl triazole derivatives. The synthesized compounds were screened by Ellman’s method to explore the influence of D-glucosamine for AChE-inhibition activity.

Results and discussion

Chemistry

The starting material, 1,3,4,6-tetra-O-benzyl-β-D-glucosamine hydrochloride (1), was synthesized as per the literature [36], [37]. Treatment of compound 1 with triethylamine in acetonitrile followed by addition of carbon disulfide to the mixture and stirring for 2 h furnished dithiocarbamic acid salt 2. Subsequent reaction of 2 with tosyl chloride (TsCl) yielded the key glycosyl isothiocyanate product 3 (Scheme 1) [38].

Scheme 1 Synthesis of 1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-isothiocyanate (3).Reagents and conditions: (i) NaOH, p-methoxybenzaldehyde, H2O, rt; (ii) NaH, BnBr, DMF, 0°C – rt; (iii) 5 N HCl, acetone, reflux; (iv) Et3N, CS2, 0°C, 1.5 h; (v) TsCl, 0.5 h.
Scheme 1

Synthesis of 1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-isothiocyanate (3).

Reagents and conditions: (i) NaOH, p-methoxybenzaldehyde, H2O, rt; (ii) NaH, BnBr, DMF, 0°C – rt; (iii) 5 N HCl, acetone, reflux; (iv) Et3N, CS2, 0°C, 1.5 h; (v) TsCl, 0.5 h.

The glycosyl isothiocyanate 3 was treated with various hydrazides 4 to yield the glycosyl acylthiosemicarbazide derivatives 5a–l. Compounds 5 were cyclized in 3 N sodium hydroxide solution for 5 h to furnish the glycosyl triazoles 6a–l in high yield (Scheme 2) [39].

Scheme 2 Synthesis of products 6.Reagents and conditions: (i) ArCONHNH2 (4a–l), acetonitrile, reflux; (ii) 3 N NaOH, reflux.
Scheme 2

Synthesis of products 6.

Reagents and conditions: (i) ArCONHNH2 (4a–l), acetonitrile, reflux; (ii) 3 N NaOH, reflux.

Biological activity

The AChE-inhibition activities of compounds 6 were evaluated in vitro by Ellman’s method [40], in which the AChE extracts from Electric eel were used. Their inhibitory potency is defined as the inhibition rate and the half of maximal inhibitory concentration, IC50. The results are summarized in Table 1.

Table 1

In vitro inhibitory activities of glycosyl triazoles against AchE.

CompoundArInhibition (%)aIC50 (μg/mL)
6aC6H594.07±1.365.64±0.86
6b2-C5H3S92.43±1.054.51±0.49
6c2-FC6H492.11±0.992.16±0.20
6d2-ClC6H485.51±0.489.14±0.41
6e4-OHC6H479.01±0.83–
6f4-CH3C6H494.43±1.601.46±0.25
6g4-NO2C6H464.41±3.41–
6h4-4-(N,N-di-Me)-C6H469.39±2.42–
6i4-FC6H498.38±1.053.41±0.54
6j4-ClC6H493.96±0.861.99±0.13
6k4-BrC6H587.23±0.899.68±0.89
6l4-IC6H574.42±1.55–
mb–14.46±1.49–
nc–19.80±1.84–
Tacrine98.46±0.130.0533±0.0008
Galantamine92.17±0.170.767±0.043

  1. aThe inhibition activities at the concentration of 50 μg/mL.

  2. bm stands for D-glucosamine hydrochloride.

  3. cn stands for 5-(4-methylphenyl)-1,2,4-triazole-3-thione.

As shown in Table 1, all compounds are better inhibitors of AChE than D-glucosamine hydrochloride (m). Eight of the 12 tested compounds that exhibited over 85% inhibition were subsequently evaluated for the IC50 value with tacrine and galantamine used as reference drugs. The best compound 6f shows the IC50 value of 1.461 and inhibit AChE with a dose-dependent relationship (Figure 1). Other compounds are much less active than tacrine and galantamine.

Figure 1 Dose-dependent inhibition of AChE by compound 6f. Values are means±SD, n=3.
Figure 1

Dose-dependent inhibition of AChE by compound 6f. Values are means±SD, n=3.

Conclusion

New C2-glycosyl triazole derivatives were designed, synthesized and subjected to biological evaluation. The AChE inhibitor activity data revealed that most of the synthesized compounds are active against acetyl cholinesterase enzymes. The present study finds that it is ineffective to remove the benzyl group by catalytic hydrogenation using Pd/C or Pd(OH)2/C due to the poisoning of the catalyst by the sulfur atom in the molecule. In the following work, we will be searching for other methods to solve this problem.

Experimental

Chemistry

All chemicals were purchased from commercial sources and used without further purification. All reactions were monitored by thin layer chromatography (TLC) using plates and visualized with 254 nm ultra violet (UV) light. Melting points were determined on a Yanaco melting point apparatus and are uncorrected. Infra red (IR) spectra were recorded on a Bruker Tensor 27 spectrometer with KBr pellets. 1H NMR spectra were recorded with a Bruker Avance spectrometer at 500 Hz using tetramethylsilane (TMS) as an internal standard and DMSO-d6 as a solvent. ESI-HRMS analysis was performed on an Agilent 6500 mass spectrometer. Flash column chromatography was performed using a silica gel 200–300 mesh.

Preparation of 2-amino-1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose hydrochloride (1)

Sodium hydroxide (1.86 g, 46.5 mmol) was added to a solution of D-glucosamine hydrochloride (10 g, 46.4 mmol) in water (70 mL) at room temperature with stirring followed by dropwise addition of p-methoxybezaldehyde (5.7 mL, 46.6 mmol) 15 min later. The mixture was stirred at ambient temperature for an additional 24 h, after which time the resulting white solid was filtrated and washed with 500 mL water to afford 2-(4-methoxy benzylidene)-2-deoxy-β-D-glucopyranose (11.4 g, 83%). A mixture of this product (6.6 g, 22.2 mmol) and BnBr (14 mL, 117.9 mmol) in DMF (50 mL) was treated portion-wise at 0°C with NaH (60%, 5 g, 125 mmol) and then stirred at room temperature for 12 h. After addition of a large amount of water, the mixture was extracted with dichloromethane (3×50 mL). The extract was concentrated under reduced pressure and the resultant yellow viscous liquid was dissolved in acetone (100 mL). Treatment of this solution with hydrochloric acid (7 mL, 5 N) and heating under reflux for 1 h afforded a white solid of 1. The product was filtered off and washed with acetone: yield 7.9 g, (62%).

Synthesis of 2-isothiocyanato-1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose (3)

To a solution of 1,3,4,6-tetra-O-benzyl-β-D-glucosamine hydrochloride (1,1 mmol) in acetonitrile (15 mL) was added triethylamine (3 mmol). The mixture was cooled in an ice bath, treated dropwise via a syringe pump with carbon disulfide (1 mmol) and stirred for 2 h. Then tosyl chloride (TsCl) (1 mmol) was added and the mixture was stirred for an additional 0.5 h. Product 3 was crystallized from ethanol; yield 90%, white amorphous powder; mp 55–56°C; IR: v 3433, 3030, 2873, 2078, 1454, 1359, 1313, 1068 cm−1; 1H NMR: δ 7.48–7.19 (m, 20H), 4.81 (dd, J=10.0 Hz and 5.0 Hz, 4H), 4.74–4.63 (m, 2H), 4.61–4.48 (m, 3H), 3.94–3.86 (m, 2H), 3.68–3.47 (m, 3H), 3.54 (t, J=9.0 Hz, 1H). ESI-HRMS. Calcd for C35H35NNaO5S, [M+Na]+: m/z 604.2128. Found: m/z 604.2130.

General procedure for the preparation of compounds 6a–l

Glycosyl isothiocyanate 3 (0.581 g, 1 mmol) was added in one portion to a stirred solution of hydrazide 4a–l (1 mmol) in MeCN (10 mL). The mixture was heated under reflux for 3–4 h and then concentrated under reduced pressure to give 5a–l. Without purification, 5a–l was added to 3 N sodium hydroxide aqueous solution (20 mL). The mixture was heated under reflux for 5–6 h and then extracted with dichloromethane (3×10 mL). The extract was washed with water, dried over anhydrous sodium sulfate and concentrated. Compound 6a–l was purified by silica gel column chromatography eluting with AcOEt/petroleum ether.

5-Phenyl-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6a)

Yield 88%, white solid; mp 139–140°C; IR: v 3431 (NH), 3088 (C-H, Ph), 2927 (CH2-Ph), 1557 (C=N), 1359 (C=S), 1048 cm−1 (C-O-C); 1H NMR: δ 14.08 (s, 1H), 7.57–7.44 (m, 5H, Ar-H), 7.36–7.24 (m, 14H, Ar-H), 7.23–7.19 (m, 2H, Ar-H), 7.18–7.12 (m, 2H, Ar-H), 7.07–7.03 (m, 2H, Ar-H), 6.21 (d, J=8.0 Hz, 1H, HGlu-1), 5.65 (dd, J=10.0 Hz and 8.0 Hz, 1H, HGlu-3), 4.82 (d, J=12.0 Hz, 1H, PhCH2), 4.71 (dd, J=11.0 Hz and 4.0 Hz, 2H, PhCH2), 4.59–4.48 (m, 4H, PhCH2), 4.41 (d, J=11.0 Hz, 1H, PhCH2), 3.93 (t, J=9.0 Hz, 1H, HGlu-4), 3.75–3.63 (m, 3H, HGlu-5,6,6), 3.50 (t, J=8.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H42N3O5S, [M+H]+: m/z 700.2840. Found: m/z 700.2832.

5-(2-Thienyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6b)

Yield 93%, pale yellow solid; mp 145–146°C; IR: v 3447 (NH), 3073 (C-H, Ph), 2929 (CH2-Ph), 1582 (C=N), 1359 (C=S), 1076 cm−1 (C-O-C); 1H NMR: δ 14.13 (s, 1H, -NH), 7.86 (d, J=5.0 Hz, 1H, thiophene), 7.46 (d, J=5.0 Hz, 1H, thiophene), 7.39–7.31 (m, 7H, Ar-H), 7.30–7.20 (m, 10 H, Ar-H), 7.15–7.10 (m, 2H, Ar-H, thiophene ), 7.02 (s, 2H, Ar-H), 6.18 (d, J=8.5 Hz, 1H, HGlu-1), 5.59 (t, J=9.0 Hz, 1H, HGlu-3), 4.82 (d, J=12.0 Hz, 1H, PhCH2), 4.74–4.68 (m, 2H, PhCH2), 4.60–4.51 (m, 4H, PhCH2), 4.39 (d, J=11.5 Hz, 1H, PhCH2), 4.15 (t, J=9.0 Hz, 1H, HGlu-4 ), 3.77–3.64 (m, 4H, HGlu-5,6,6′), 3.58 (t, J=9.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C40H40N3O5S2, [M+H]+: m/z 706.2406. Found: m/z 706.2405.

5-(2-Fluorophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6c)

Yield 91%, white solid; mp 112–113°C; IR: v 3433 (NH), 3089 (C-H, Ph), 2925 (CH2-Ph), 1560 (C=N), 1359 (C=S), 1059 cm−1 (C-O-C); 1H NMR: δ 14.25 (s, 1H, -NH), 7.68–7.60 (m, 1H, Ar-H), 7.42 (t, J=9.0 Hz, 1H, Ar-H), 7.38–7.25 (m, 16H, Ar-H), 7.20 (d, J=7.0 Hz, 2H, Ar-H), 7.15 (d, J=7.0 Hz, 2H, Ar-H), 7.10 (d, J=4.5 Hz, 2H, Ar-H), 6.12 (d, J=8.0 Hz, 1H, HGlu-1), 5.61 (t, J=9.0 Hz, 1H, HGlu-3), 4.80 (d, J=12.5 Hz, 1H, PhCH2), 4.73–4.65 (m, 2H, PhCH2), 4.58–4.43 (m, 5H, PhCH2), 3.73–3.58 (m, 4H, HGlu-4,5,6,6′), 3.47 (t, J=9.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H41FN3O5S, [M+H]+: m/z 718.2745. Found: m/z 718.2744.

5-(2-Chlorophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6d)

Yield 84%, white solid; mp 106–107°C; IR: v 3421 (NH), 3063 (C-H, Ph), 2926 (CH2-Ph), 1604 (C=N), 1361 (C=S), 1061 cm−1 (C-O-C); 1H NMR: δ 14.18 (s, 1H, -NH), 7.62–7.34 (m, 3H, Ar-H), 7.33–7.24 (m, 15H, Ar-H), 7.23–7.16 (m, 4H, Ar-H), 7.15–7.13 (m, 2H, Ar-H), 6.11 (d, J=8.0 Hz, 1H, HGlu-1), 5.63 (t, J=9.0 Hz, 1H, HGlu-3), 4.88–4.73 (m, 2H, PhCH2), 4.71–4.61 (m, 1H, PhCH2), 4.56–4.45 (m, 5H, PhCH2), 3.69 (t, J=9.0 Hz, 1H, HGlu-4), 3.68–3.47 (m, 3H, HGlu-5,6,6′), 3.45 (t, J=9.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H40ClN3NaO5S, [M+Na]+: m/z 756.2269. Found: m/z 756.2265.

5-(4-Hydroxyphenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6e)

Yield 82%, white solid; mp 96–97°C; IR: v 3418 (NH), 3201 (O-H), 3062 (C-H, Ph), 2924 (CH2-Ph), 1513 (C=N), 1386 (C=S), 1053 cm−1 (C-O-C); 1H NMR: δ 13.92 (s, 1H, -NH), 10.07 (s, 1H, OH), 7.38–7.24 (m, 16H, Ar-H), 7.21 (d, J=7.0 Hz, 2H, Ar-H), 7.14 (d, J=7.0 Hz, 2H, Ar-H), 7.03 (d, J=7.0 Hz, 2H, Ar-H), 6.83 (d, J=8.0 Hz, 2H, Ar-H), 6.20 (d, J=8.0 Hz, 1H, HGlu-1), 5.62 (t, J=9.0 Hz, 1H, HGlu-3), 4.81 (d, J=12.5 Hz, 1H, PhCH2), 4.68 (dd, J=11.0, 7.5 Hz, 2H, PhCH2), 4.59–4.49 (m, 4H, PhCH2), 4.38 (d, J=11.0 Hz, 1H, PhCH2), 3.95 (t, J=9.0 Hz, 1H, HGlu-4), 3.75–3.62 (m, 3H, HGlu-5,6,6′), 3.50 (t, J=9.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H42N3O6S, [M+H]+: m/z 716.2789. Found: m/z 716.2785.

5-(4-Methylphenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6f)

Yield 88%, white solid; mp 136–137°C; IR: v 3439 (NH), 3089 (C-H, Ph), 2948 (CH2-Ph), 1516 (C=N), 1360 (C=S), 1057 cm−1 (C-O-C); 1H NMR: δ 14.02 (s, 1H, NH), 7.39–7.32 (m, 7H, Ar-H), 7.31–7.25 (m, 11H, Ar-H), 7.24–7.20 (m, 2H, Ar-H), 7.17–7.12 (m, 2H, Ar-H), 7.07–7.02 (m, 2H, Ar-H), 6.20 (d, J=8.0 Hz, 1H, HGlu-1 ), 5.63 (t, J=8.5 Hz, 1H, HGlu-3), 4.82 (d, J=12.0 Hz, 1H, PhCH2), 4.71 (d, J=11.0 Hz, 2H, PhCH2), 4.58–4.48 (m, 4H, PhCH2), 4.40 (d, J=11.0 Hz, 1H, PhCH2), 3.92 (t, J=8.5 Hz, 1H, HGlu-4), 3.75–3.63 (m, 3H, HGlu-5,6,6′), 3.49 (t, J=8.0 Hz, 1H, HGlu-2), 3.30 (s, 3H, CH3). ESI-HRMS. Calcd for C43H44N3O5S, [M+H]+: m/z 714.2996. Found: m/z 714.2999.

5-(4-Nitrophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6g)

Yield 79%, yellow solid; mp 103–104°C; IR: v 3424 (NH), 3090 (C-H, Ph), 2924 (CH2-Ph), 1559 (C=N), 1347 (C=S), 1057 cm−1 (C-O-C); 1H NMR: δ 14.28 (s, 1H, -NH), 8.41–8.31 (m, 2H, Ar-H), 7.82–7.69 (m, 2H, Ar-H), 7.44–6.99 (m, 20H, Ar-H), 6.19 (t, J=8.0 Hz, 1H, HGlu-1), 5.63 (t, J=8.5 Hz, 1H, HGlu-3), 4.81 (t, J=11.0 Hz, 1H, PhCH2), 4.77–4.67 (m, 2H, PhCH2), 4.60–4.48 (m, 4H, PhCH2), 4.41 (t, J=10.0 Hz, 1H, PhCH2), 3.89 (t, J=8.5 Hz, 1H, HGlu-4), 3.75–3.63 (m, 3H, HGlu-5,6,6), 3.56 (t, J=8.5 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H41N4O7S, [M+H]+: m/z 745.2690. Found: m/z 745.2694.

5-(4-N,N-Dimethylphenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6h)

Yield 81%, pale yellow solid; mp 131–132°C; IR: v 3423 (NH), 3087 (C-H, Ph), 2868 (CH2-Ph), 1614 (C=N), 1362 (C=S), 1058 cm−1 (C-O-C); 1H NMR: δ 13.87 (s, 1H), 7.37–7.25 (m, 16H, Ar-H), 7.25–7.21 (m, 2H, Ar-H), 7.17–7.13 (m, 2H, Ar-H), 7.06–7.02 (m, 2H, Ar-H), 6.75 (d, J=9.0 Hz, 2H, Ar-H), 6.22 (d, J=8.0 Hz, 1H, HGlu-1), 5.64 (dd, J=10.5 Hz and 8.0 Hz, 1H, HGlu-3), 4.83 (d, J=12.5 Hz, 1H, PhCH2), 4.69 (t, J=10.0 Hz, 2H, PhCH2), 4.59–4.49 (m, 4H, PhCH2), 4.40 (d, J=11.0 Hz, 1H, PhCH2), 4.03 (dd, J=10.5, 8.5 Hz, 1H, HGlu-4), 3.75–3.63 (m, 3H, HGlu-5,6,6′), 3.49 (t, J=8.0 Hz, 1H, HGlu-2), 2.95 (s, 6H, -CH3). ESI-HRMS. Calcd for C44H45N4NaO5S, [M+Na]+: m/z 765.3081. Found: m/z 765.3072.

5-(4-Fluorophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6i)

Yield 87%, white solid; mp 127–128°C; IR: v 3429 (NH), 3063 (C-H, Ph), 2869 (CH2-Ph), 1611 (C=N), 1361 (C=S), 1058 cm−1 (C-O-C); 1H NMR: δ 14.25 (s, 1H, -NH), 7.68–7.60 (m, 1H, Ar-H), 7.42–7.25 (m, 17H, Ar-H), 7.20–7.10 (m, 6H, Ar-H), 6.12 (d, J=8.0 Hz, 1H, HGlu-1), 5.61 (dd, J=10.0, 8.5 Hz, 1H, HGlu-3), 4.80 (d, J=12.0 Hz, 1H, PhCH2), 4.73–4.65 (m, 2H, PhCH2), 4.58–4.43 (m, 5H, PhCH2), 3.75–3.58 (m, 4H, HGlu-4,5,6,6′), 3.47 (t, J=8.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H41FN3O5S, [M+H]+: m/z 718.2745. Found: m/z 718.2748.

5-(4-Chlorophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6j)

Yield 85%, white solid; mp 123–124°C. IR: v 3446 (NH), 3088 (C-H, Ph), 2941 (CH2-Ph), 1606 (C=N), 1361 (C=S), 1057 cm−1 (C-O-C); 1H NMR: δ 14.12 (s, 1H, -NH), 7.53–7.48 (m, 2H, Ar-H), 7.38–7.26 (m, 16H, Ar-H), 7.25–7.21 (m, 2H, Ar-H), 7.17–7.12 (m, 2H, Ar-H), 7.07–7.03 (m, 2H, Ar-H), 6.19 (d, J=8.0 Hz, 1H, HGlu-1), 5.63 (dd, J=10.0, 8.0 Hz, 1H, HGlu-3), 4.82 (d, J=12.5 Hz, 1H, PhCH2), 4.71 (dd, J=11.0 Hz and 5.0 Hz, 2H, PhCH2), 4.60–4.48 (m, 4H, PhCH2), 4.40 (d, 1H, J=11.0 Hz, PhCH2), 3.87 (dd, J=10.5, 8.0 Hz, 1H, HGlu-4), 3.75–3.63 (m, 3H, HGlu-5,6,6), 3.52 (t, J=8.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H41ClN3O5S, [M+H]+: m/z 734.2450. Found: m/z 734.2447.

5-(4-Bromophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6k)

Yield 90%, white solid; mp 132–133°C. IR: v 3427 (NH), 3086 (C-H, Ph), 2941 (CH2-Ph), 1602 (C=N), 1357 (C=S), 1058 cm−1 (C-O-C); 1H NMR: δ 14.17 (s, 1H, NH), 7.75 (d, J=7.0 Hz, 2H, Ar-H), 7.40–7.24 (m, 18H, Ar-H), 7.16–6.95 (m, 4H, Ar-H), 6.19 (d, J=7.0 Hz, 1H, HGlu-1), 5.62 (t, J=8.5 Hz, 1H, HGlu-3), 4.82 (d, J=11.5 Hz, 1H, PhCH2), 4.76–4.64 (m, 2H, PhCH2), 4.57–4.47 (m, 4H, PhCH2), 4.40 (d, J=10.5 Hz, 1H, PhCH2), 3.88 (t, J=8.0 Hz, 1H, HGlu-4), 3.71–3.65 (m, 3H, HGlu-5,6,6′), 3.54 (t, J=8.0 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H41BrN3O5S, [M+H]+: m/z 778.1945. Found: m/z 778.1942.

5-(4-Iodophenyl)-4-(1,3,4,6-tetra-O-benzyl-2-deoxy-β-D-glucopyranose-2-yl)-1,2,4-triazole-3-thione (6l)

Yield 77%; pale yellow solid; mp 127–128°C; IR: v 3428 (NH), 3087 (C-H, Ph), 2928 (CH2-Ph), 1600 (C=N), 1360 (C=S), 1027 cm−1 cm−1 (C-O-C); 1H NMR: δ 14.12 (s, 1H, NH), 7.90 (d, J=7.5 Hz, 2H, Ar-H), 7.40–7.21 (m, 18H, Ar-H), 7.14 (d, J=7.5 Hz, 2H, Ar-H), 7.04 (d, J=7.0 Hz, 2H, Ar-H), 6.19 (d, J=8.0 Hz, 1H, HGlu-1), 5.61 (t, J=8.5 Hz, 1H, HGlu-3), 4.81 (d, J=12.5 Hz, 1H, PhCH2), 4.70 (d, J=11.0 Hz, 2H, PhCH2), 4.60–4.47 (m, 4H, PhCH2), 4.39 (d, J=11.0 Hz, 1H, PhCH2), 3.88 (t, J=9.0 Hz, 1H, HGlu-4), 3.75–3.60 (m, 3H, HGlu-5,6,6), 3.54 (t, J=8.5 Hz, 1H, HGlu-2). ESI-HRMS. Calcd for C42H4IN3NaO5S, [M+Na]+: m/z 848.1626. Found: m/z 848.1621.

In vitro cholinesterase activity assay

Acetylcholinesterase (AChE), acetylthiocholine iodide (ATCI), 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB), galantamine and tacrine were purchased from Sigma-Aldrich (USA). AChE activities were measured using Ellman’s colorimetric method with a slight modification [38] with galantamine and tacrine as the reference compounds. An electric eel AChE was dissolved in 0.1 m phosphate-buffered saline (PBS, pH 8.0) to obtain a solution of 0.35 U/mL. In assays, 20 μL of AChE was incubated with 10 μL of tested compounds and 130 μL of 0.1 m PBS (pH 8.0) for 10 min in 96-well microplates before the addition of 20 μL of 3.33 mm DTNB solution and 20 μL of 5.30 mm ATCI solution. After the addition of DTNB and ATCI, the 96-well microplates were read at 412 nm with a microplate reader (Spectrafluor, Austria) for 15 min. One triplicate sample without inhibitors was always present to yield 100% of AChE activity. The reaction rates were compared and the percentage inhibition due to the presence of tested compounds was calculated. Galantamine and tacrine were applied as positive controls. All samples were assayed in triplicate. The 50% inhibitory concentration (IC50) was calculated from a dose-response curve obtained by plotting the percentage of inhibition vs. the log concentration with the use of Origin 8.0 software. The results were described as the mean±standard deviation.

Acknowledgments

This work was supported by the Priority Academic Development Program of Jiangsu Higher Education Institutions, Natural Science Foundation of Jiangsu Province (BK20151281), Open-end Funds of Jiangsu Key Laboratory of Marine Biotechnology (HS2014007), the Science and Technology Project of Lianyungang (CG1415) and Public Science and Technology Research Funds Projects of Ocean (201505023).

References

[1] Yamada, K.; Kakehi, K. Recent advances in the analysis of carbohydrates for biomedical use. J. Pharm. Biomed. Anal.2011, 55, 702–727.10.1016/j.jpba.2011.02.003Search in Google Scholar PubMed

[2] Dingjan, T.; Spendlove, I.; Durrant, L. G.; Scott, A. M.; Yuriev, E.; Ramsland, P. A. Structural biology of antibody recognition of carbohydrate epitopes and potential uses for targeted cancer immunotherapies. Mol. Immunol.2015, 67, 75–88.10.1016/j.molimm.2015.02.028Search in Google Scholar PubMed

[3] Delbianco, M.; Bharate, P.; Varela-Aramburu, S.; Seeberger, P. H. Carbohydrates in supramolecular chemistry. Chem. Rev.2016, 116, 1693–1752.10.1021/acs.chemrev.5b00516Search in Google Scholar PubMed

[4] Ernst, B.; Magnani, J. L. From carbohydrate leads to glycomimetic drugs. Nat. Rev. Drug Discov.2009, 8, 661–677.10.1038/nrd2852Search in Google Scholar PubMed PubMed Central

[5] Lin, C. I.; McCarty, R. M.; Liu, H. W. The biosynthesis of nitrogen-, sulfur-, and high-carbon chain-containing sugars. Chem. Soc. Rev.2013, 42, 4377–407.10.1039/c2cs35438aSearch in Google Scholar PubMed PubMed Central

[6] Bertozzi, C. R.; Kiessling, L. L. Chemical glycobiology. Science2001, 291, 2357–2364.10.1126/science.1059820Search in Google Scholar PubMed

[7] Xu, C.; Hall, R.; Cummings, J.; Raushel, F. M. Tight binding inhibitors of N-acyl amino sugar and N-acyl amino acid deacetylases. J. Am. Chem. Soc.2006, 128, 4244–4245.10.1021/ja0600680Search in Google Scholar PubMed

[8] Azuma, K.; Osaki, T.; Wakuda, T.; Tsuka, T.; Imagawa, T.; Okamoto, Y.; Minami, S. Suppressive effects of N-acetyl-D-glucosamine on rheumatoid arthritis mouse models. Inflammation2012, 35, 1462–1465.10.1007/s10753-012-9459-0Search in Google Scholar PubMed

[9] Bottegoni C.; Muzzarelli R. A. A.; Giovannini F.; Busilacchi A.; Gigante A. Oral chondroprotection with nutraceuticals made of chondroitin sulphate plus glucosamine sulphate in osteoarthritis. Carbohyd. Polym.2014, 109, 126–138.10.1016/j.carbpol.2014.03.033Search in Google Scholar PubMed

[10] Chu, S. C.; Yang, S. F.; Lue, K. H.; Hsieh, Y. S.; Lee, C. Y.; Chou, M. C.; Lu, K. H. Glucosamine sulfate suppresses the expressions of urokinase plasminogen activator and inhibitor and gelatinases during the early stage of osteoarthritis. Clin. Chim. Acta2006, 372, 167–172.10.1016/j.cca.2006.04.014Search in Google Scholar PubMed

[11] Hua, J.; Suguro, S.; Hirano, S.; Sakamoto, K.; Nagaoka, I. Preventive actions of a high dose of glucosamine on adjuvant arthritis in rats. Inflamm. Res.2005, 54, 127–132.10.1007/s00011-004-1333-6Search in Google Scholar PubMed

[12] Xing, R.; Liu, S.; Guo, Z.; Yu, H.; Li, C.; Ji, X.; Feng, J.; Li, P. The antioxidant activity of glucosamine hydrochloride in vitro. Bioorg. Med. Chem.2006, 14, 1706–1709.10.1016/j.bmc.2005.10.018Search in Google Scholar PubMed

[13] Blagodatskikh, I. V.; Kulikov, S. N.; Vyshivannaya, O. V.; Bezrodnykh, E. A.; Yamskov, I. A.; Tikhonov, V. E. Influence of glucosamine on oligochitosan solubility and antibacterial activity. Carbohydr. Res.2013, 381, 28–32.10.1016/j.carres.2013.08.012Search in Google Scholar PubMed

[14] Quastel, J. Inhibition of tumour growth by D-glucosamine. Nature1953, 171, 252–254.10.1038/171252a0Search in Google Scholar PubMed

[15] Lee, J.; Katzenmaier, E. M.; Kopitz, J.; Gebert, J. Reconstitution of TGFBR2 in HCT116 colorectal cancer cells causes increased LFNG expression and enhanced N-acetyl-d-glucosamine incorporation into Notch1. Carbohydr. Res.2016, 28, 1105–1113.10.1016/j.cellsig.2016.04.012Search in Google Scholar PubMed

[16] Liu, W. W.; Li, Q. X.; Shi, D. H. Synthesis, characterization, and biological evaluation of some novel glycosyl 1,3,4-thiadiazole derivatives as acetylcholinesterase inhibitors. Heterocycles2015, 91, 275–286.10.3987/COM-14-13134Search in Google Scholar

[17] Pawlak, D.; Stolarska, M.; Wojciechowski, M.; Andruszkiewicz, R. Synthesis, anticandidal activity of N3-(4-methoxyfumaroyl)-(S)-2,3-diaminopropanoic amide derivatives–Novel inhibitors of glucosamine-6-phosphate synthase. Eur. J. Med. Chem.2015, 90, 577–582.10.1016/j.ejmech.2014.12.007Search in Google Scholar PubMed

[18] Kun, S.; Nagy, G. Z.; Tóth, M.; Czecze, L.; Van Nhien, A. N.; Docsa, T.; Gergely, P.; Charavgi, M. D.; Skourti, P. V.; Chrysina, E. D. Synthesis of variously coupled conjugates of D-glucose, 1,3,4-oxadiazole, and 1,2,3-triazole for inhibition of glycogen phosphorylase. Carbohydr. Res.2011, 346, 1427–1438.10.1016/j.carres.2011.03.004Search in Google Scholar PubMed

[19] Bera, S.; Linhardt, R. J. Design and synthesis of unnatural heparosan and chondroitin building blocks. J. Org. Chem.2011, 76, 3181–3193.10.1021/jo200076zSearch in Google Scholar PubMed PubMed Central

[20] Jung, M. E.; Dong, T. A.; Cai, X. Improved synthesis of 4-amino-7-nitrobenz-2,1,3-oxadiazoles using NBD fluoride (NBD-F). Tetrahedron Lett.2011, 52, 2533–2535.10.1016/j.tetlet.2011.02.111Search in Google Scholar

[21] Garifullin, B. F.; Strobykina, I. Y.; Sharipova, R. R.; Kravchenko, M. A.; Andreeva, O. V.; Bazanova, O. B.; Kataev, V. E. Synthesis and antituberculosis activity of the first macrocyclic glycoterpenoids comprising glucosamine and diterpenoid isosteviol. Carbohydr. Res.2016, 431, 15–24.10.1016/j.carres.2016.05.007Search in Google Scholar PubMed

[22] Keemink, J.; Wuyts, B.; Nicolaï, J.; De Jonghe, S.; Stella, A.; Herdewijn, P.; Augustijns, P.; Annaert, P. In vitro disposition profiling of heterocyclic compounds. Int. J. Pharm.2015, 491, 78–90.10.1016/j.ijpharm.2015.05.080Search in Google Scholar PubMed

[23] Chen, Y.; Yu, K.; Tan, N. Y.; Qiu, R. H.; Liu, W.; Luo, N. L.; Tong, L.; Au, C.-T.; Luo, Z. Q.; Yin, S. F. Synthesis, characterization and anti-proliferative activity of heterocyclic hypervalent organoantimony compounds. Eur. J. Med. Chem.2014, 79, 391–398.10.1016/j.ejmech.2014.04.026Search in Google Scholar PubMed

[24] Dighe, S. U.; Khan, S.; Soni, I.; Jain, P.; Shukla, S.; Yadav, R.; Sen, P.; Meeran, S. M.; Batra, S. Synthesis of β-carboline-based N-heterocyclic carbenes and their antiproliferative and antimetastatic activities against human breast cancer cells. J. Med. Chem.2015, 58, 3485–3499.10.1021/acs.jmedchem.5b00016Search in Google Scholar PubMed

[25] Barbuceanu, S. F.; Saramet, G.; Almajan, G. L.; Draghici, C.; Barbuceanu, F.; Bancescu, G. New heterocyclic compounds from 1,2,4-triazole and 1,3,4-thiadiazole class bearing diphenylsulfone moieties. Synthesis, characterization and antimicrobial activity evaluation. Eur. J. Med. Chem.2012, 49, 417–423.10.1016/j.ejmech.2012.01.031Search in Google Scholar PubMed

[26] Li, B. L.; Li, B.; Zhang, R. L.; Zhao, J. J.; Wang, X. F.; Liu, Y. M.; Shi, Y. P.; Liu, J. B.; Chen, B. Q. Synthesis and antiproliferative evaluation of novel 1,2,4-triazole derivatives incorporating benzisoselenazolone scaffold. Bioorg. Med. Chem. Lett.2016, 26, 1279–1281.10.1016/j.bmcl.2016.01.017Search in Google Scholar PubMed

[27] Witkowski, J. T.; Robins, R. K.; Khare, G. P.; Sidwell, R. W. Synthesis and antiviral activity of 1,2,4-triazole-3-thiocarboxamide and 1,2,4-triazole-3-carboxamidine ribonucleosides. J. Med. Chem.1973, 16, 935–937.10.1021/jm00266a014Search in Google Scholar PubMed

[28] Sarigol, D.; Uzgoren-Baran, A.; Tel, B. C.; Somuncuoglu, E. I.; Kazkayasi, I.; Ozadali-Sari, K.; Unsal-Tan, O.; Okay, G.; Ertan, M.; Tozkoparan, B. Novel thiazolo [3,2-b]-1,2,4-triazoles derived from naproxen with analgesic/anti-inflammatory properties: Synthesis, biological evaluation and molecular modeling studies. Bioorg. Med. Chem.2015, 23, 2518–2528.10.1016/j.bmc.2015.03.049Search in Google Scholar PubMed

[29] Siddiqui, N.; Alam, M.; Ahsan, W. Synthesis, anticonvulsant and toxicity evaluation of 2-(1H-indol-3-yl) acetyl-N-(substituted phenyl) hydrazine carbothioamides and their related heterocyclic derivatives. Acta Pharmaceut.2008, 58, 445–454.10.2478/v10007-008-0025-0Search in Google Scholar PubMed

[30] Munawar, M. A.; Chattha, F. A.; Kousar, S.; Munir, J.; Ismail, T.; Ashraf, M.; Khan, M. A. Synthesis of novel triazoles and a tetrazole of escitalopram as cholinesterase inhibitors. Bioorg. Med. Chem.2015, 23, 6014–6024.10.1016/j.bmc.2015.06.051Search in Google Scholar PubMed

[31] Mohammadi-Khanaposhtani, M.; Mahdavi, M.; Saeedi, M.; Sabourian, R.; Safavi, M.; Khanavi, M.; Foroumadi, A.; Shafiee, A.; Akbarzadeh, T. Design, synthesis, biological evaluation, and docking study of acetylcholinesterase inhibitors: new acridone-1,2,4-oxadiazole-1,2,3-triazole hybrids. Chem. Biol. Drug Des.2015, 86, 1425–1432.10.1111/cbdd.12609Search in Google Scholar PubMed

[32] Mohammadi-Khanaposhtani, M.; Saeedi, M.; Zafarghandi, N. S.; Mahdavi, M.; Sabourian, R.; Razkenari, E. K.; Alinezhad, H.; Khanavi, M.; Foroumadi, A.; Shafiee, A. Potent acetylcholinesterase inhibitors: design, synthesis, biological evaluation, and docking study of acridone linked to 1, 2, 3-triazole derivatives. Eur. J. Med. Chem.2015, 92, 799–806.10.1016/j.ejmech.2015.01.044Search in Google Scholar PubMed

[33] Singh, H.; Kumar, M.; Nepali, K.; Gupta, M. K.; Saxena, A. K.; Sharma, S.; Bedi, P. M. S. Triazole tethered C5-curcuminoid-coumarin based molecular hybrids as novel antitubulin agents: Design, synthesis, biological investigation and docking studies. Eur. J. Med. Chem.2016, 116, 102–115.10.1016/j.ejmech.2016.03.050Search in Google Scholar PubMed

[34] Ramprasad, J.; Nayak, N.; Dalimba, U. Design of new phenothiazine-thiadiazole hybrids via molecular hybridization approach for the development of potent antitubercular agents. Eur. J. Med. Chem.2015, 106, 75–84.10.1016/j.ejmech.2015.10.035Search in Google Scholar PubMed

[35] Caldwell, N.; Harms, J. E.; Partin, K. M.; Jamieson, C. Rational design of a novel AMPA receptor modulator through a hybridization approach. ACS Med. Chem. Lett.2015, 6, 392–396.10.1021/ml5004553Search in Google Scholar PubMed PubMed Central

[36] Liu, W.; Li, Q.; Cheng, F.; Shi, D.; Cao, Z. Synthesis of novel glycosyl 1,3,4-oxadiazole derivatives. Heterocycl. Commun.2014, 20, 333–338.10.1515/hc-2014-0166Search in Google Scholar

[37] Tao, C. Z.; Liu, F.; Liu, W. W.; Zhu, Y. M.; Li, Y. F.; Liu, X. L.; Zhao, J. Synthesis of N-aryl-d-glucosamines through copper-catalyzed C–N coupling. Tetrahedron Lett.2012, 53, 7093–7096.10.1016/j.tetlet.2012.10.069Search in Google Scholar

[38] Cheng, F. C.; Yin, L.; Liu, W. W.; Li, Q. X.; Tang, L. J.; Shi, D. H.; Cao, Z. L. Expedient synthesis of novel glycosyl thiazole derivatives. Heterocycles2015, 91, 2113–2125.10.3987/COM-15-13310Search in Google Scholar

[39] Li, C.; Liu, J. C.; Li, Y. R.; Gou, C.; Zhang, M. L.; Liu, H. Y.; Li, X. Z.; Zheng, C. J.; Piao, H. R. Synthesis and antimicrobial evaluation of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety. Bioorg. Med. Chem. Lett.2015, 25, 3052–3056.10.1016/j.bmcl.2015.04.081Search in Google Scholar PubMed

[40] Ellman, G. L.; Courtney, K. D.; Andres, V.; Featherstone, R. M. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem. Pharmacol.1961, 7, 88–95.10.1016/0006-2952(61)90145-9Search in Google Scholar PubMed

Received: 2016-9-28
Accepted: 2017-1-11
Published Online: 2017-6-9
Published in Print: 2017-6-27

©2017 Walter de Gruyter GmbH, Berlin/Boston

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. Carbohydrate chemistry/glycoscience
  4. Reviews
  5. Boron-based small molecules in disease detection and treatment (2013–2016)
  6. Impact of modified ribose sugars on nucleic acid conformation and function
  7. Preliminary Communication
  8. Crystallization-induced amide bond formation creates a boron-centered spirocyclic system
  9. Research Articles
  10. Anion and sugar recognition by 2,6-pyridinedicarboxamide bis-boronic acid derivatives
  11. Synthesis of biotinylated bivalent zanamivir analogs as probes for influenza viruses
  12. Synthesis of silodosin glucuronide and its deuterated counterpart: solving a problematic O-glycosylation of a nitrogen-containing molecule
  13. Synthesis and antimicrobial activity of 4-trifluoromethylpyridine nucleosides
  14. Synthesis of anti-inflammatory 2,3-unsaturated O-glycosides using conventional and microwave heating techniques
  15. Synthesis of various β-D-glucopyranosyl and β-D-xylopyranosyl hydroxybenzoates and evaluation of their antioxidant activities
  16. Synthesis of carbohydrate-substituted isoxazoles and evaluation of their antitubercular activity
  17. Synthesis and bioactivity of novel C2-glycosyl triazole derivatives as acetylcholinesterase inhibitors
  18. Modification of bovine serum albumin with aminophenylboronic acid as glycan sensor based on surface plasmon resonance and isothermal titration calorimetry
https://doi.org/10.1515/hc-2016-0163
Keywords for this article
acetylcholinesterase; C2-glycosyl triazole derivatives; synthesis
Creative Commons
BY-NC-ND 3.0

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. Carbohydrate chemistry/glycoscience
  4. Reviews
  5. Boron-based small molecules in disease detection and treatment (2013–2016)
  6. Impact of modified ribose sugars on nucleic acid conformation and function
  7. Preliminary Communication
  8. Crystallization-induced amide bond formation creates a boron-centered spirocyclic system
  9. Research Articles
  10. Anion and sugar recognition by 2,6-pyridinedicarboxamide bis-boronic acid derivatives
  11. Synthesis of biotinylated bivalent zanamivir analogs as probes for influenza viruses
  12. Synthesis of silodosin glucuronide and its deuterated counterpart: solving a problematic O-glycosylation of a nitrogen-containing molecule
  13. Synthesis and antimicrobial activity of 4-trifluoromethylpyridine nucleosides
  14. Synthesis of anti-inflammatory 2,3-unsaturated O-glycosides using conventional and microwave heating techniques
  15. Synthesis of various β-D-glucopyranosyl and β-D-xylopyranosyl hydroxybenzoates and evaluation of their antioxidant activities
  16. Synthesis of carbohydrate-substituted isoxazoles and evaluation of their antitubercular activity
  17. Synthesis and bioactivity of novel C2-glycosyl triazole derivatives as acetylcholinesterase inhibitors
  18. Modification of bovine serum albumin with aminophenylboronic acid as glycan sensor based on surface plasmon resonance and isothermal titration calorimetry
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 12.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/hc-2016-0163/html
Scroll to top button