INTRODUCTION:

Aziridines are three-membered ring heterocycles that include nitrogen and are well-known for their employment as reactive intermediates in the production of chiral amino alcohols, azomethine ylides, and derivatives of amino acids¹. Furthermore, they find application as chiral ligands and auxiliaries in asymmetric synthesis² and fused heterocycles³.

Aziridine-containing compounds are important as reactive intermediates, but because of the aziridine ring, they also have a variety of biological actions, particularly antibacterial and anticancer ones⁴. Stabilized ethyleneimine has a flash point of 12°F, is colorless and clear, and is less thick than water. It smells like ammonia. It can catch fire at several different amounts of vapor in the air. Its vapor irritates the throat, nose, eyes, and skin. By prolonged inhalation, skin absorption, or ingestion, aziridine may be harmful. It causes cancer. gases that are denser than air. Perhaps polluted or heated to an exothermic polymerization. A container may suddenly burst if the polymerization occurs inside of it⁵.

Figure 1. Chemical structure of Aziridine: Ethyleneimine

Molecular formula: CH₂NHCH₂

Molecular weight: 43.07 g/mol

Strong alkylating agents, aziridine’s in-vivo potency is mostly determined by toxicity as opposed to particular activity. Aziridine derivatives' toxicity is based on their structural makeup. Several significant natural products, including carzinophilin A, porfiromycin, and mitomycin C⁶, are well-known in the literature as biologically active substances. Aziridine ring opening and contact with DNA's guanine nucleobase during the alkylation reaction are necessary for mitomycin C's physiological effects. This causes the production of covalent interstrand DNA–DNA crosslinks, replication inhibition, and ultimately cell death. Currently, aziridines possessing the amide function are of particular interest, with Imexon being a well-known example. Imexon is an anticancer drug that is particularly effective against human myeloma cells. It works by attaching to cellular thiols and lowering glutathione and cysteine levels in the target cells, which raises reactive oxygen species (ROS). Consequently, the cells begin an apoptotic pathway, caspase 3 and 9 are activated, mitochondria enlarge, and cytochrome c is released⁷. It is also known that imexon alters the endoplasmic reticulum's redox balance, which prevents protein translation and halts cell growth. It has been effectively used in combination with docetaxel in the experimental treatment of several malignancies⁸. Additional research linking Imexon's action to the inhibition of B-lymphocyte activation revealed that it could be helpful in treating B-cell or plasma cell lymphomas or neoplasias, some autoimmune diseases, and viral infections of the Rauscher leukemia virus⁹.

MATERIALS AND METHODS:

Materials:

Substituted-2-imine, DMSO, glacial acetic acid, ethanol, sulfuric acid, distilled water and paraffin. Spectrophotometer, NMR Spectrophotometer, Mass Spectrophotometer, ChemDraw software, SwissDock software.

Synthesis of novel derivatives of aziridine:

Figure 2. Scheme for synthesis of aziridine derivatives

All the 12 novel derivatives were synthesized using above scheme. These were evaluated for physiochemical parameters, spectroscopy and docking.

A. Identification of physicochemical properties:

Boiling point:

Invert a capillary tube into the liquid and heat it. As the temperature increases, the liquid's vapor pressure increases and pushes out the air in the tube, causing bubbles to form at the bottom. When the vapor pressure inside the tube equals the atmospheric pressure, liquid will begin to enter the tube. The temperature at which this happens is the boiling point¹⁰.

Rf value:

Thin layer chromatography, or TLC for short, is a technique in synthetic chemistry that uses a compound's variable Rf value to deduce the molecule's synthesis. It also helps to validate the reaction's advancement¹¹.

Infrared Spectroscopy:

One classifies the infrared spectrum as a vibrational-rotational spectrum. For solid compounds, the KBr pellet technique is utilized; for liquid compounds, the Nujol mull method is employed. It is a very useful document that provides details about the functional groups found in organic molecules. When electromagnetic radiation with a wavelength spanning from 500 cm-1 to 4000 cm-1 passes through a sample, the mechanism of bond stretching and bending occurs¹².

NMR Spectroscopy:

Proton NMR is the most widely utilized NMR method due to its high sensitivity and extensive characteristic information. The chemical shift (δ) range is 0–14 ppm. The test unknown compound's chemical shift was compared to TMS protons, which had an attribution of 0 ppm. However, the shift extends to the component for the organic compound range δ 0–14¹³.

Mass Spectroscopy:

An essential physico-chemical tool for determining the structures of chemicals found in natural goods, such as medicinal herbs, is mass spectrometry. The application of various physical techniques for sample ionization and ion generation based on mass to charge ratio (m/z) is the fundamental idea of mass spectrometry. Electrospray ionization, air pressure chemical ionization, electron ionization, chemical ionization, rapid atom bombardment, and matrix analysis laser desorption ionization are among the ionization techniques that are accessible. Compared to NMR, which has a sensitivity limit of the nanogram range and above, mass spectrometry has a high sensitivity with a detection limit of the fentogram. MS is a versatile analytical tool because to its sensitivity and versatility for hypenation with other chromatographic techniques¹⁴.

B. Docking study:

Melanoma inhibitory activity protein (PDB ID: 1F9G) molecular docking calculations performed using the docking software EADock DSS and the SwissDock (http://swissdock.vital-it.ch/) online service. This web-based service was chosen due to its easy-to-use interface, which allows users to alter docking parameters, enter necessary protein and ligand structures straight from databases, and view the most advantageous clusters online. Chemsketch was used to depict the structure of the compounds, and energy minimization was applied. Binding modes were grouped after being given a FullFitness score. Next, based on the average FullFitness of their constituent parts, clusters were ordered. The UCSF Chimera package was used to visualize the SwissDock results¹⁵.

RESULT:

Synthesis of novel derivatives of aziridine:

A10

A11

A12

Identification of novel derivatives of aziridine

Physicochemical properties:

Following table 1. summarizes the physicochemical properties:

Table 1. Physicochemical properties of aziridine derivatives

Compound	Yield (%)	Rf Value	Boiling point
A 1	43.52	0.69	182ºC
A 2	46.26	0.72	176ºC
A 3	44.65	0.74	194ºC
A 4	48.24	0.72	210ºC
A 5	47.49	0.76	192ºC
A 6	44.28	0.72	218ºC
A 7	49.72	0.77	166ºC
A 8	42.56	0.74	172ºC
A 9	45.29	0.69	189ºC
A 10	48.39	0.72	186ºC
A 11	43.78	0.74	206ºC
A 12	49.12	0.72	196ºC

Mass Spectroscopy:

A1: ESI-MS: m/z (% rel. abundance): 239 (10) [M+2]⁺, 238 (16) [M+1]⁺, 237 (100) [M]⁺, 127 (20), 99 (10), 71(20), 43 (12).

A2: ESI-MS: m/z (% rel. abundance): 249 (16) [M+1]⁺, 248 (100) [M]⁺, 127 (12), 99 (10), 71(12), 43 (8).

A3: ESI-MS: m/z (% rel. abundance): 282 (16) [M+1]⁺, 281 (100) [M]⁺, 127 (33), 99 (32), 71(11), 43 (6).

A4: ESI-MS: m/z (% rel. abundance): 222 (17) [M+1]⁺, 221 (100) [M]⁺, 127 (13), 99 (22), 71(24), 43 (12).

A5: ESI-MS: m/z (% rel. abundance): 330 (20) [M+1]⁺, 329 (100) [M]⁺, 127 (40), 99 (32), 71(32), 43 (18).

A6: ESI-MS: m/z (% rel. abundance): 334 (12) [M+1]⁺, 333 (100) [M]⁺, 127 (37), 99 (32), 71(32), 43 (26).

A7: ESI-MS: m/z (% rel. abundance): 220 (16) [M+1]⁺, 219 (100) [M]⁺, 127 (36), 99 (35), 71(11), 43 (8).

A8: ESI-MS: m/z (% rel. abundance): 218 (16) [M+1]⁺, 217 (100) [M]⁺, 127 (22), 99 (12), 71(21), 43 (15).

A9: ESI-MS: m/z (% rel. abundance): 204 (16) [M+1]⁺, 203 (100) [M]⁺, 127 (19), 99 (16), 71(18), 43 (14).

A10: ESI-MS: m/z (% rel. abundance): 229 (16) [M+1]⁺, 228 (100) [M]⁺, 127 (16), 99 (24), 71(17), 43 (14).

A11: ESI-MS: m/z (% rel. abundance): 261 (16) [M+1]⁺, 260 (100) [M]⁺, 127 (37), 99 (36), 71(14), 43 (10).

A 12: ESI-MS: m/z (% rel. abundance): 219 (16) [M+1]⁺, 218 (100) [M]⁺, 127 (18), 99 (26), 71(28), 43 (16).

FTIR Spectroscopy:

A1: IR (KBr)n: 2939 (Aromatic C-H str.), 2817 (Aliphatic C-H str.), 1799 (C=O str.), 1674 (Aromatic CC str.), 1583 (Aromatic C-C Str.), 1419 (Cyclic Aliphatic C-N str.), 1174 (Aliphatic C-N str.), 761 (Aromatic C-Cl str.), 844 (C-H p-disubstituted benzene (def.)).

A2: FTIR spectrum analysis: IR (KBr)n: 3070 (Aromatic C-H str.), 2937 (Aliphatic C-H str.), 1708 (C=O str.), 1610 (Aromatic CC str.), 1505 (Aromatic C-C Str.), 1348 (N-O str.), 1276 (Cyclic Aliphatic C-N str.), 1180 (Aliphatic C-N str.), 744 (C-H p-disubstituted benzene).

A3:FTIR spectrum analysis: IR (KBr)n: 3134 (Aromatic C-H str.), 2947(Aliphatic C-H str.), 1608 (C=O str.), 1548 (Aromatic CC str.), 1499 (Aromatic C-C Str.), 1296 (Cyclic Aliphatic C-N str.), 1180 (Aliphatic C-N str.), 690 (C-H p-disubstituted benzene (def.)), 549 (Ar. C-Br str.).

A4: FTIR spectrum analysis: IR (KBr)n: 3109 (Aromatic C-H str.), 2933(Aliphatic C-H str.), 1595 (C=O str.), 1550 (Aromatic CC str.), 1500 (Aromatic C-C Str.), 1254 (Cyclic Aliphatic C-N str.), 1157 (Aliphatic C-N str.), 1026 (Ar. C-F str.), 831 (C-H p-disubstituted benzene.

A5: FTIR spectrum analysis: IR (KBr)n: 3060 (Aromatic C-H str.), 2904(Aliphatic C-H str.), 1654(C=O str.), 1579 (Aromatic CC str.), 1473 (Aromatic C-C Str.), 1238(Cyclic Aliphatic C-N str.), 1153 (Aliphatic C-N str.), 838 (C-H p-disubstituted benzene (def.)), 453 (Ar. C-I str.).

A6: FTIR spectrum analysis: IR (KBr)n: 3076 (Aromatic C-H str.), 2933(Aliphatic C-H str.), 1722 (C=O str.), 1613 (Aromatic CC str.), 1506 (Aromatic C-C Str.), 1276(Cyclic Aliphatic C-N str.), 1180 (Aliphatic C-N str.), 1070 (C-O-C str.), 847 (C-H p-disubstituted benzene).

A7: FTIR spectrum analysis: IR (KBr)n: 3414 (Aromatic O-H str.), 3093 (Aromatic C-H str.), 2977 (Aliphatic C-H str.), 1618 (C=O str.), 1540 (Aromatic CC str.), 1461 (Aromatic C-C Str.), 1274 (Cyclic Aliphatic C-N str.), 1182 (Aliphatic C-N str.), 721 (C-H p-disubstituted benzene).

A8: FTIR spectrum analysis: IR (KBr)n: 3070 (Aromatic C-H str.), 2937 (Aliphatic C-H str.), 1708 (C=O str.), 1610 (Aromatic CC str.), 1508 (Aromatic C-C Str.), 1276 (Cyclic Aliphatic C-N str.), 1180 (Aliphatic C-N str.), 744 (C-H p-disubstituted benzene).

A 9: FTIR spectrum analysis: IR (KBr)n: 3056 (Aromatic C-H str.), 2995 (Aliphatic C-H str.), 1760 (C=O str.), 1620 (Aromatic CC str.), 1556 (Aromatic C-C Str.), 1271 (Cyclic Aliphatic C-N str.), 1209 (Aliphatic C-N str.).

A 10: FTIR spectrum analysis: IR (KBr)n: 3037 (Aromatic C-H str.), 2935 (Aliphatic C-H str.), 1664 (C=O str.), 1623 (Aromatic CC str.), 1454 (Aromatic C-C Str.), 1282 (Cyclic Aliphatic C-N str.), 1244 (Aliphatic C-N str.), 829 (C-H p-disubstituted benzene).

A 11: FTIR spectrum analysis: IR (KBr)n: 3380 (N-H str.), 3049 (Aromatic C-H str.), 2831 (Aliphatic C-H str.), 1772 (C=O str.), 1664 (Aromatic CC str.), 1498 (Aromatic C-C Str.), 1332 (Cyclic Aliphatic C-N str.), 1226 (Aliphatic C-N str.), 834 (C-H p-disubstituted benzene).

A 12: FTIR spectrum analysis: IR (KBr)n: 3337 (N-H str.), 3075 (Aromatic C-H str.), 2925 (Aliphatic C-H str.), 1680 (C=O str.), 1623 (Aromatic CC str.), 1454 (Aromatic C-C Str.), 1325 (Cyclic Aliphatic C-N str.), 1282 (Aliphatic C-N str.), 806 (C-H p-disubstituted benzene).

NMR Spectroscopy

A1: ¹H NMR (DMSO-d₆): d 1.10-1.12 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.32-7.38 (m, 2H, Ar–H), 7.83-7.89 (m, 2H, Ar–H).

A2: ¹H NMR (DMSO-d₆): d 1.11-1.18 (m, 6H, CH₃), 1.54 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 8.03-8.19 (m, 2H, Ar–H), 8.21-8.89 (m, 2H, Ar–H).

A3: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.41-7.52 (m, 2H, Ar–H), 7.72-7.79 (m, 2H, Ar–H).

A4: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.01-7.05 (m, 2H, Ar–H), 7.78-7.89 (m, 2H, Ar–H).

A5: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.62-7.69 (m, 2H, Ar–H), 7.69-7.78 (m, 2H, Ar–H).

A6: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 6.81-6.87 (m, 2H, Ar–H), 7.71-7.78 (m, 2H, Ar–H).

A7:¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 5.0 (s, 1H, OH), 6.81-6.87 (m, 2H, Ar–H), 7.71-7.78 (m, 2H, Ar–H).

A8: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.35 (s, 3H, CH₃), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.12-7.17 (m, 2H, Ar–H), 7.71-7.78 (m, 2H, Ar–H).

A9:¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.32-7.39 (m, 2H, Ar–H), 7.44 (s, 1H, CH), 7.81-7.89 (m, 2H, Ar–H).

A 10: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.51-7.59 (m, 2H, Ar–H), 8.01-8.09 (m, 2H, Ar–H).

A 11: ¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.02 (s, 3H, CH₃), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 7.71-7.7.78 (m, 2H, Ar–H), 7.82-7.89 (m, 2H, Ar–H), 8.0 (s, 1H, NH).

A 12:¹H NMR (DMSO-d₆): d 1.10-1.18 (m, 6H, CH₃), 1.53 (s, 2H, CH₂), 2.55 (t, 2H, CH₂), 2.65 (t, 2H, CH₂), 4.0 (s, 2H, NH₂), 7.51-7.59 (m, 2H, Ar–H), 7.61-7.69 (m, 2H, Ar–H).

Docking study:

Our molecular docking investigations for an aziridine derivative that has the antioxidant activity protein's active binding site finished have been completed. It is established how much binding energy is needed to generate an enzyme-ligand combination. The drugs' target-specific binding affinity towards the antioxidant inhibitory activity protein is derived from the molecular atomic level of interactions (Table 2). With a binding energy of -6 to -9 Kcal/mol, every chemical has demonstrated effective docking inside the antioxidant activity protein's active region. We contrasted the anticipated docking data with proteins known to have antioxidant action.

Table 2. Binding affinity of aziridine derivatives

Compound No.	R₁	R₂	R₃	Fullfitness (Kcal/mol)	Binding Energy (ΔG) (Kcal/mol)
A 1	-CH₃	-CH₃	-Cl	-1483.69	-9.05
A 2	-CH₃	-CH₃	-NO₂	-1472.45	-7.46
A 3	-CH₃	-CH₃	-Br	-1483.79	-7.17
A 4	-CH₃	-CH₃	-F	-1485.54	-8.23
A 5	-CH₃	-CH₃	-I	-1485.57	-7.23
A 6	-CH₃	-CH₃	-OCH₃	-1481.77	-7.30
A 7	-CH₃	-CH₃	-OH	-1493.40	-6.74
A 8	-CH₃	-CH₃	-CH₃	-1484.51	-7.19
A 9	-CH₃	-CH₃	-H	-1483.29	-7.02
A 10	-CH₃	-CH₃	-CN	-1500.65	-7.18
A 11	-CH₃	-CH₃	-NHCOCH₃	-1501.28	-7.06
A 12	-CH₃	-CH₃	-NH₂	-1490.79	-7.22
Standard	Ascorbic acid			-1985.42	-9.34

The % yield was observed as 48.24, 49.72, 48.39 and 49.12 in compound A4, A7, A10 and A12, respectively. Highest Rf values were observed in A3, A5, A7 and A 11 as 0.74, 0.76, 0.77, and 0.74, respectively. A4 showed boiling point 210ºC. Based on docking study, all the compounds were found active, however compound A1, and A4 were demonstrated the highest binding energy (Affinity). Derivatives of aziridine A2, A3, A5, A6, A8, A9, A10, A11, A12 were found also found active with some moderate binding affinity.

CONCLUSION:

Along with their potent anticancer properties, natural aziridine alkaloids and their lipophilic semi-synthetic and synthetic equivalents also have potent antibacterial properties. It concluded that 12 novel derivatives of aziridine were synthesized and characterized with their physicochemical properties and spectral analysis (NMR, Mass, FTIR). In docking study, compounds A1 and A4 demonstrated the highest binding affinity among all 12 aziridine derivatives. Thus, active aziridine derivatives might be used in the evaluation of the biological potential. It suggests to perform the acute oral toxicity of the synthesized aziridine derivatives and antioxidant activity.

CONFLICT OF INTEREST:

The authors have no conflicts of interest regarding this investigation.

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Received on 01.06.2024 Modified on 09.07.2024

Research J. Pharm. and Tech 2024; 17(8):3983-3991.

DOI: 10.52711/0974-360X.2024.00618