Synthesis, Characterization and Attenuation of Strychnine-Induced Epilepsy on 3-(3-Aminophenyl)- 1-[3-(2-Hydroxyphenyl)-3-Oxopropanoyl]-5,5-Diphenylimidazolidine-2,4-Dione Derivatives on Experimental Rats

The nucleus of imidazolidine was found in 1954. It has an imidazolidine ring and dibenzene bonded together. The medication phenytoin and its structure are similar.¹ Because 5, 5-diphenylimidazolidine has so many pharmacological uses, it has an essential heterocyclic nucleus (refer to Figure 1).² These days, 5, 5-diphenylimidazolidine is the preferred moiety due to its many pharmacological characteristics.

Although there are over forty different anti-epileptic medications on the Indian market,³ barely thirty percent of individuals with uncontrollable seizures have found relief.⁴ Thus, a lot of research is being done on antiepileptic compounds these days. Its primary goal is to investigate novel anticonvulsant medications.⁵ Based on the kind of seizure, in vivo screening assays were used to identify these compounds.⁶ Seizures are defined as aberrant electrical activity in the brain and are characterised by the physical alterations in a patient’s behaviour that take place during therapy.⁷ When a patient experiences a seizure, there is an issue with disorganised brain activity. Generally speaking, an excess of patient brain cells becoming activated at the same moment causes a seizure. Seizures can be divided into two categories: partial and generalised.⁸ While partial seizures occur when electrical activity spikes in only one area of the brain, generalised seizures involve aberrant electrical activity on both sides of the patient’s brain.⁹ There are several causes of seizures, including elevated blood sugar or salt levels, brain damage after a stroke, or issues related to head trauma.¹⁰ Patients may occasionally have brain tumours from birth. Alzheimer’s disease, elevated fevers, illicit drug usage and alcohol or drug withdrawal are some conditions that might result in seizures.¹¹

2-chloromethyl benzene; 1-phenyl methanone; 4-oxo-4-phenoxybutanoic acid; 1-phenyl ethanone; phenol acetate; 4-aminophenol; oxalic acid etc., were used for the synthesis. Every chemical was of the analytical variety. All of the chemicals were bought from Modern Chemicals in Nashik, while others are offered by the college.

The standard approach was utilised to synthesise all 5, 5-diphenylimidazolidine derivatives. Through the use of thin layer chromatography techniques, the compounds’ purity was examined (TLC). KBr pellets were used to produce IR spectra using the Perkin Elmer Spectrum FTIR instrument, 1H-NMR spectra. The synthetic routes for (BD) derivatives were shown in Scheme 1A and Scheme 1B.

4 g of 2-hydroxy-1,2-diphenylethanone and 14 mL of concentrated HNO₃ is heated in an RBF over a hot water bath for 11 min. Following the reaction, add 75 mL of water to the mixture, allow it to cool, recrystallize it using 10 mL of ethanol. To attain the cloud point, add water dropwise once the substance has dissolved. Permit the product to re-solidify. After the material has re-crystallized and allow it to dry.

Pour 100 mL of RBF with 5.3 g of benzoyl. 3.0 g of urea was added to that RBF. Next, add 15 mL of 30% aq. Sodium hydroxide, or NaOH Add 75 mL of C₂H₅OH (ethanol) last. Connect the reflux condenser and then use the heating mantle to boil under reflux for at least 2 hr. Bring the temperature down. After 10 min of standing, filter using a suction pump to get rid of any insoluble by product. Use concentrated HCl to render the product filtrate with very acidic acid. After cooling in ice water, remove PPT right away.

Scheme 1A:
Synthesis of 3-(3-aminophenyl)-1-[3-(2-hydroxyphenyl)-3-oxopropanoyl]]-5,5-diphenylimidazolidine-2,4-dione (BD).

Scheme 1B:
Synthesis of 3-(3-aminophenyl)-1-[3-(2-hydroxyphenyl)-3-oxopropanoyl]]-5,5-diphenylimidazolidine-2,4-dione (BE-BN).

Add 1 g of phenytoin to the flask with a round bottom. To the 100 mL RBF, add 1 mL of glacial acetic acid and 3 amino phenols. Refluxing the reaction mixture, heat it for 2 hr at a temperature between 80 and 100°C. Add 10 mL of crushed ice to the reaction mixture to cool it down. Pour in more ice-cold water. Gather the product after filtering the reaction mixture.

Put 2 g of (BC)-(scheme 1A) with 100 mL RBF, add 50 mL ethanol and 1 g 2-hydroxy benzoic acid. For two and a half hour, reflux the reaction mixture between 80 and 100^oC. Crushed ice water (5 mL) is added to cool the reaction mixture. Gather the product after filtering the reaction mixture.

Put 2 g of BD (scheme 1A) in a flask with a round bottom, 25 mL of ethanol and 2 mL of nitro aniline, the reaction mixture is heated for an hour while experiencing reflux. To obtain the product, filter it and then recrystallize it using ethanol.

Put 1 g of BD (scheme 1A) in a flask with a round bottom, to which 25 mL of ethanol and 1 mL of 4-nitro aniline are added. After heating the reaction cool. To get the product, filter the reaction mixture and then dry it and recrystallize it using ethanol.

Put 2 g of BD (Scheme 1A) in a flask with a round bottom, reflux the reaction mixture after adding 30 mL of ethanol (used as a solvent) and 5 mL of 2-chloromethyl benzene. After heating the reaction cool. To get the product, filter the reaction mixture and then dry it and recrystallize it using ethanol.

Put 2 g of BD (scheme 1A) in a flask with a round bottom in 30 mL of ethanol with 2 g of 1-phenyl methanone. Give it a good shake. For 1 hr, heat the reaction mixture cool to room temperature after an hour. Let it stand for 5 min. To obtain the product, filter it, then dry it and recrystallize it using ethanol.

Put 2 g of 3 BD (scheme 1A) in a flask with a round bottom and include 30 mL of ethanol and 2 mL of 4-oxo-4-phenoxybutanoic acid. For 1 hr, heat the reaction mixture to allow it to cool when the reaction is finished. After the result has been filtered, dried and recrystallized with ethanol.

Put 2 g of BD (Scheme 1A) in a flask with a round bottom and add 2 mL of 1-phenyl ethanone. Heat the reaction mixture under reflux conditions for 30 min at a constant 50 degrees. Set the RBF aside for a few minutes when the response is finished. Incorporate ice water into the blend. To get the product, filter, dry and then recrystallize.

Put 2 g of BD (scheme 1A) in a flask with a round bottom, together with 30 mL of ethanol, 2 g of aniline. For 1 hr, the reaction mixture is heated. After the result has been filtered, dried and recrystallized with ethanol

Put 2 g of 3 BD (scheme 1A) in a flask with a round bottom and include 30 mL of ethanol and 2 g of phenol acetate. For one and a half hours, heat the mixture to allow it to cool when the reaction is finished. After filtering, dry the item combined it with ethanol to form a crystal to produce.

Put 2 g of BD (scheme 1A) in a flask with a round bottom together with 30 mL of ethanol, 2 g of oxalic acid. For 1 hr, the reaction mixture is heated, when the reaction is finished. After the product has been filtered, dried and recrystallized with ethanol.

Put 2 g of BD (scheme 1A) in a flask with a round bottom and combine with 30 mL of ethanol and 2 g of 4-aminophenol. For one and a half hours, heat the mixture then cool when the reaction is finished. After filtering, dry the item. Using ethanol recrystallized it to produce a product.

FTIR (KBr) ν cm^-1: 1957.39 C=C Stretch (Aromatic), 1186.01 C-C Stretch (Aromatic), 1341.88 C-N Stretch (Aromatic), 3275.55 N-H Stretch (Aromatic), 1712.26 C=O Stretch (Aryl ketone) 728.13 O-H (Bend); 1H NMR (400 MHz, DMSO): δ 12.17 Ar N-H (s, 1H), δ 8.721-7.158 Ar C-H (m, 19H), δ 3.3 CH₃ Group (s, 3H), 5.2 O-H Group (s,1H).

FTIR (KBr) ν cm^-1: 1949.68 C=C Stretch (Aromatic), 1020.16 C-C Stretch (Aromatic), 1340.18 C-N Stretch (Aromatic), 3275.5 N-H Stretch (Aromatic), 1715.98 C=O Stretch (Aryl ketone), 700.99 O-H (Bend), 1409.71 S=O Stretch, 1183.11 O-H sulfonic acid; 1H NMR (400 MHz, DMSO): δ 11.506 Ar N-H (s, 1H), δ 5.1 O-H (s, 1H), δ 8.717-7.158 Ar C-H (m, 20H), δ 4.348 CH₂ Group (s, 2H), δ 3.3 CH₃ Group (s, 3H).

FTIR (KBr) ν cm^-1: 1953.54 C=C Stretch (Aromatic),1068.59 C-C Stretch (Aromatic), 1266.75 C-N Stretch (Aromatic), 3267.49 N-H Stretch (Aromatic), 1710.69 C=O Stretch (Aryl ketone), 778.13 O-H (Bend), 1402.0 S=O Stretch, 1173.11 O-H sulfonic acid; 1H NMR (400 MHz, DMSO): δ 12.075 Ar N-H (s, 1H), δ 8.471-6.949 Ar C-H (m, 20H), δ 5.4 O-H (s, 1H).

FTIR (KBr) ν cm^-1: 1934.25 C=C Stretch (Aromatic), 1124.3 C-C Stretch (Aromatic),3238.7 N-H Stretch (Aromatic), 1714.55 C=O (Aryl Ketone), 886.13 O-H (Bend), 1433.12 S=O Stretch, 1128.1 O-H sulfonic acid; 1H NMR (400 MHz, DMSO): δ 10.695 Ar N-H (s, 1H), δ 8.464-7.927 Ar C-H (m, 19H), δ 5.0 O-H (s, 1H).

FTIR (KBr) ν cm^-1: 1880.26 C=C Stretch (Aromatic), 3298.64 N-H Stretch (Aromatic), 1714.27 C=O Stretch (Aryl ketone), 887.09 O-H (Bend), 1428.32 S=O Stretch, 1147.44 O-H sulfonic acid; 1H NMR (400 MHz, DMSO): δ 12.955 Ar N-H (s, 1H), δ 8.266-7.483 Ar C-H (m, 19H), δ 5.334 O-H (s, 1H).

FTIR (KBr) ν cm^-1: 1872.54 C=C Stretch (Aromatic), 1139.72 C-C Stretch (Aromatic), 1270.86 C-N Stretch (Aromatic), 3306.36 N-H Stretch (Aromatic), 1718.38 C=O Stretch (Aryl ketone), 908.30 O-H (Bend), 1140.14 O-H sulfonic acid; 1H NMR (400 MHz, DMSO): δ 13.088 Ar N-H (s, 1H), δ 7.893-7.236 Ar C-H (m, 18H), δ 5.589 O-H (s, 1H).

FTIR (KBr) ν cm^-1:1886.60 C=C Stretch (Aromatic), 1138.90 C-C Stretch (Aromatic), 1319.60 C-N Stretch (Aromatic), 3398.4 N-H Stretch (Aromatic), 1718.60 C=O (Aryl ketone), 1319.60 C-O Stretch (Aromatic), 948.57 O-H (Bend), 1129.34 O-H Stretch sulfonic acid;; 1H NMR (400 MHz, DMSO): δ 12.955 Ar N-H (s, 1H), δ 8.266-7.483 Ar C-H (m, 19H), δ 5.33 O-H (s, 1H).

FTIR (KBr) ν cm^-1: 1951.54.06 C=C Stretch (Aromatic),1065.59 C-C Stretch (Aromatic), 1261.75 C-N Stretch (Aromatic), 3260.49 N-H Stretch (Aromatic), 1710.69 C=O Stretch (Aryl ketone), 1735.31 C=O Stretch (Ester), 779.13 O-H (Bend), 1401.0 S=O Stretch, 1171.11 O-H sulfonic acid; 1H NMR (400 MHz, DMSO): δ 11.075 Ar N-H (s, 1H), δ 8.471-6.949 Ar C-H (m, 19H), δ 5.1 O-H (s, 1H).

The anti-convulsant properties of newly synthesised 5,5-diphenylimidazolidin-1-yl derivatives were examined. Eleven compounds in total three step products and eight 5,5-diphenylimidazolidin-1-yl derivatives were assessed for biological screening. The anticonvulsant action is briefly described in the section that follows.

Several 5,5-diphenylimidazolidin-1-yl derivatives are useful in treating tonic-clonic (grand mal) seizures, which are characterised by widespread seizures.¹² Because strychnine is such a potent toxin, a minimal dose is required to cause convulsions. Using an intravenous Strychnine paradigm, the synthetic compounds’ anticonvulsant efficacy was assessed by screening them against Strychnine.¹³ The fundamental idea behind the anti-convulsant test is to compare the produced molecules to the reference drug, phenytoin. Comparing the duration of convulsions, the start of action in seconds (sec.), the percentage of protection (%protection) and other factors should be done to draw a conclusion.¹⁴ This sc Strychnine model uses strychnine as a negative control. In order to choose the dose for the standard and negative control, the S.K. Kulkarni practical book was used. The Wistar Rats will be divided into six groups. Each group consists of six animals (n = 6) who receive therapy for 10 days.¹⁵ The first group will get distilled water as the control vehicle, while the second group will receive the traditional medication. Phenytoin 100 mg/kg is used in it. On the 10^th day, 60 min preceding the previous dosage, 85 mg/kg of strychnine was administered into each group to cause convulsions in the rats.¹⁶ The results of the anticonvulsant activity tests of the generated compounds were shown in Table 1 and Figure 2.

Figure 3:
5, 5-diphenylimidazolidine heterocyclic nucleus.

Figure 4:
Comparison chart of Anticonvulsant Activity of 5,5-diphenylimidazolidin-1-yl derivative at different concentrations.

The technique 1B was followed in the synthesis of Novel Substituted 5,5-diphenylimidazolidin-1-yl derivatives from BE to BN. Additionally, the response mixture was mixed for the duration indicated in the table below at room temperature. After that, the strong product was cleaned with distilled water and dried to produce smooth goods in excellent yields, ranging from BE to BN. Table 2 presents a comparative chart, which shows the convulsion activity of novel substituted 5,5-diphenylimidazolidin-1-yl derivatives at varying concentrations. The methods include low, middle and high doses, with the aim of minimising seizure spread. The typical medication was phenytoin 100 mg/kg. For the following 30 min, each animal will be watched separately to see if it exhibits convulsions. Table 2 summarises the anti-convulsant results of the named compounds (BE to BN). Compounds BN and BJ demonstrated protection at a maximal dose level of 200 mg/Kg and for the following 30 min; each animal will be monitored separately for convulsion behaviour. At the highest dose level (100 mg/kg), compound BN and BJ showed protection and over the following 30 min, each animal will be watched separately for convulsion behaviour. At lower dosage levels (50 mg/kg), compounds BN and BJ containing aromatic groups demonstrated reduced protection against convulsions that were generated. Table 2 displayed the anti-convulsant test findings for the produced compounds. The anti-convulsant properties of recently synthesised compounds were investigated using the Strychnine Induced Convulsion Method. Oral administration at a dosage of 100 mg/kg was used to test each chemical. Table 2 displays the study’s findings. It’s noteworthy to note that every chemical in the current series exhibited some degree of anti-convulsion properties. The data suggest that all of the BN and BJ had stronger anti-convulsant effects than the ones that matched them. In comparison to their 5,5-diphenylimidazolidin-1-yl derivatives, nitro aniline derivatives showed reduced percentage suppression of convulsion but superior efficacy overall. The most active compounds were found to be BM, BG and BE, which have amino groups at the ortho, meta and para positions on the phenyl ring. These compounds were investigated at three different dosage levels (200 mg/kg orally). Of the newly synthesised compounds, compound BI demonstrated the most powerful and dose-dependent anti-convulsant action. The efficacy of novel substituted 5,5-diphenylimidazolidin-1-yl derivatives to prevent seizure spread at different concentrations, such as low, middle and high doses, is demonstrated by a comparison chart see Figure 2 and Table 2. For the following 30 min, each animal will be watched separately for convulsive behaviour. Table 2 summarises the anticonvulsant results of compounds named BE to BN. Compounds BM and BG demonstrated protection at a maximal dosage level of 200 mg/kg and for the following 30 min, each animal will be monitored separately for convulsive behaviour. Compounds BF and BE showed protection at the highest dose level (100 mg/kg) and for the following 30 min, each animal will be watched separately for convulsive behaviour. At lower dosage levels (50 mg/kg), compounds BF and BE containing aromatic groups demonstrated weaker protection against provoked seizures. Table 2 and Figure 2 display the findings of the produced compounds’ anticonvulsant activity testing.

The 5,5-diphenylimidazolidin-1-yl reported in this work, in conclusion, has remarkable drug-like properties, low neurotoxicity and strong anticonvulsive activity, all of which suggest their potential for use in the development of new anticonvulsant medications. More action was discovered when synthesised compounds were compared to other phenytoin at 100 mg/kg. Finally, it was demonstrated that a range of 5,5-diphenylimidazolidin-1-yl derivatives (BE to BN) and their more hydrophobic counterparts (BE to BN) were effective anticonvulsants in vivo. More than half of the chemicals in the BE to BN family showed anticonvulsant efficacy in models of induced seizures.

The authors are thankful to Dr. S.B. Bhawar, Pravara Rural College of Pharmacy, Pravaranagar.