Semicarbazone, thiosemicarbazone tailed isoxazoline-pyrazole: synthesis, DFT, biological and computational assessment.

Aim: A series of semicarbazone and thiosemicarbazone-tailed hybrids comprising pyrazole and acetylisoxazoline were prepared from (R)-carvone and characterized by technique spectroscopies Nuclear Magnetic Resonance (NMR), IR and High-Resolution Mass Spectrometry. Density Functional Theory (DFT) determined the structural parameters. Their cytotoxic activity was evaluated in vitro against four human cancer cell lines.Methods & results: All the studied semi and thiosemicarbazone demonstrate a promising potential as anticancer agents. The mechanism of action of these compounds involves apoptosis in HT-1080 cells, supported by an increase in the level of caspase-3/7 activity, which also arrests the cell cycle in the G0/G1 phase. Molecular docking studies were performed to establish the potential of the most active compounds 4a and 5a. ADMET analysis showed appropriate pharmacokinetic properties, allowing structure prediction for anticancer activity.

[Box: see text].

Thiazolidinone-linked-1,2,3-triazoles with (R)-Carvone as new potential anticancer agents.

Aim: This study explores the cytotoxic and apoptotic effects of novel thiazolidinone-1,2,3-triazole hybrids on HT-1080, A-549, and MDA-MB-231 cancer cell lines.Methods & results: The synthesized compounds underwent comprehensive characterization (NMR and HRMS) to confirm their structures and purity. Subsequent anticancer activity screening across diverse cancer cell lines revealed promising antitumor potential notably, compounds 6f and 6g. Mechanistic investigations unveiled that compound 6f triggers apoptosis through the caspase-3/7 pathway. In terms of in silico studies, the compound 6f was identified as a potent inhibitor of caspase-3 and caspase-7.Conclusion: The present study underscores the therapeutic potential of thiazolidinone-1,2,3-triazole hybrids against certain cancer cells. These findings highlight a promising avenue for the development of cancer treatment strategies utilizing these (R)-Carvone-based derivatives.

[Box: see text].

Multitargeted molecular docking and dynamics simulation studies of 1,3,4-thiadiazoles synthesised from (R)-carvone against specific tumour protein markers: An In-silico study of two diastereoisomers.

In the present work, we describe the synthesis of new 1,3,4-thiadiazole derivatives from natural (R)-carvone in three steps including, dichloro-cyclopropanation, a condensation with thiosemicarbazide and then a 1,3-dipolar cycloaddition reaction with various nitrilimines. the targeted compounds were structurally identified by 1H & 13C NMR and HRMS analyses. The cytotoxic assay demonstrated that some synthesized novel compounds were potent on certain cancer cell lines. Molecular modeling studies were undertaken to rationalize the wet lab study results. Furthermore, molecular docking was performed to unveil the binding potential of the most active derivatives, 3a and 6c, to caspase-3 and COX-2. The stabilities of the protein-compound complexes obtained from the docking were evaluated using MD simulation. Furthermore, FMO and related parameters of the active compounds and their stereoisomers were examined through DFT studies. The docking study showed compound 6c had a higher binding potential than caspase-3. However, the binding strength of 6c was found to be less than that of the standard drug, doxorubicin, as it formed lower conventional hydrogen bonds. On the other hand, compound 3a had a higher binding potential to COX-2. However, the binding potential 3a was much lower than that of the standard COX-2 inhibitor, celecoxib. The MD simulation demonstrated that the caspase-3-6c complex was less stable than the caspase-3-doxorubicin complex. In contrast, the COX-2-3a complex was stable, and 3a was anticipated to remain inside the protein's binding pocket. The DFT study showed that 3a had higher chemical stability than 6c. The electron exchange capacity, chemical stability, and molecular orbital distributions of the stereoisomers of the active compounds were also found to be alike.

New (S)-verbenone-isoxazoline-1,3,4-thiadiazole hybrids: synthesis, anticancer activity and apoptosis-inducing effect.

Background: This study aimed to develop novel isoxazoline-1,3,4-thiadiazole hybrids from (S)-verbenone for potential anticancer treatment, particularly focusing on cytotoxic and apoptotic effects in hormone-sensitive MCF-7 and triple-negative MDA-MB-231 breast cancer cells. Methods & results: (S)-verbenone was used to synthesize hybrids through 1,3-dipolar cycloaddition, followed by thorough characterization. The compounds were screened across cancer cell lines, showing significant anticancer effects. Compound 8b notably induced apoptosis via the caspase-3/7 pathway and cell cycle arrest, displaying noteworthy cytotoxicity against MCF-7 and MDA-MB-231 cells. Conclusion: These findings underscore the potential of (S)-verbenone isoxazoline-1,3,4-thiadiazole derivatives for breast cancer therapy due to their remarkable apoptotic activity. This study highlights a promising avenue for advancing breast cancer treatment using these derivatives, founded on (S)-verbenone, showcasing their distinct potential for inducing apoptosis.

Discovery of a new Bcl-2 inhibitor through synthesis, anticancer activity, docking and MD simulations.

A database of 300 compounds was virtually screened and docked against Bcl-2 protein; the stability of the best-formed complex was evaluated through Molecular dynamics, the top ten compounds with the best in-silico complexation affinities were synthesized, and their In-vitro cytotoxic activity was examined. Thiazolidinone (4e) and isoxazoline (4a-d) were evaluated in-silico. For further evaluation and examination, we designed and synthesized from naturally occurring (R)-carvone and characterized it via spectroscopic analysis, as well as tested for their anticancer activities towards human cancer cell lines such as HT-1080 (fibrosarcome cancer), MCF-7 and MDA-MB-231 (breast cancer) and A-549 (lung cancer) by using MTT method with Doxorubicin as standard drug. Among them, compound 4d showed the most promising anticancer activity against HT-1080, A-549, MCF-7, and MDA-MB-231 cell lines with IC50 values of 15.59 ± 3.21 µM; 18.32 ± 2.73 µM; 17.28 ± 0.33 µM and 19.27 ± 2.73 µM respectively.Communicated by Ramaswamy H. Sarma.

Hybrids of thiazolidinone with 1,2,3-triazole derivatives: design, synthesis, biological evaluation, in silico studies, molecular docking, molecular dynamics simulations, and ADMET profiling.

A new series of thiazolidinone linked 1,2,3-triazole hybrids 5a-h was designed and synthesized using the copper-catalyzed Huisgen azide-alkyne cycloaddition (CuAAC) between thiazolidinone linked alkyne and aromatic azides. The structures of the newly synthesized compounds were established by NMR (1H and 13C) and HRMS. The targeted thiazolidinone-1,2,3-triazole hybrids were evaluated for their cytotoxic activity against four human cancer cell lines, including fibrosarcoma (HT-1080), lung carcinoma (A-549), and breast carcinoma (MCF-7 and MDA-MB-231) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliun bromide (MTT). The obtained data showed that most of these compounds have moderate anti-proliferative activity with IC50 values between 10.26 ± 0.71 and 53.93 ± 1.20 µM. The compound 5a exhibited higher activity with an IC50 value of 10.26 ± 0.71 µM, compared to 5d with an IC50 value of 11.56 ± 1.98 µM for the HT-1080 and MCF-7 cancer cells line, respectively. Moreover, Annexin-V apoptosis was assessed by flow cytometry for hybrid compounds 5a and 5d against HT-1080 and MCF-7 competitor cell lines, as they increase the level of active caspase 3/7. The experimental results were further confirmed by docking studies followed by molecular dynamic simulations. Both the potent derivatives i.e. 5a and 5d have comparable docking scores and MD simulations results showed that the docked complex of 5a is somewhat more stable than 5d primarily for protein p53. The ADMET profile of both derivatives established their safety zone and drug-like potential.Communicated by Ramaswamy H. Sarma.

Cytotoxic and apoptotic effects of some (R)-carvone-isoxazoline derivatives on human fibrosarcoma and carcinoma cells: experimental evaluation for cytotoxicity, molecular docking and molecular dynamics studies.

This study aimed to analyze the cytotoxic and apoptotic effects of isoxazoline derivatives with monoterpene scaffold 9a-e in HT-1080 fibrosarcoma, MCF-7, and MDA-MB-231 breast carcinoma, and A-549 lung carcinoma. The cytotoxic effects data revealed that compounds 9a-e generally induced significant cell growth inhibition in all cell lines, with IC50 ranging from 10 to 30 µM. However, for compounds 9c and 9e, the IC50 reached a value of 100 µM in HT-1080 cells. Compounds 9a, 9b, and 9d could induce apoptosis in HT-1080 cells as demonstrated by Annexin-V labeling and Caspase-3/7 activity. The apoptotic effect was accompanied by cell cycle arrest in the S phase. Molecular docking and molecular dynamics confirmed the empirical assay results and confirmed the stability of the complex with the inhibition of the anti-apoptotic protein, leading to cancer cell death. Overall, these data suggest that the proposed isoxazoline derivatives may be potential candidates for further investigation to evaluate their efficacy and optimal use in cancer treatment.Communicated by Ramaswamy H. Sarma.

New 1,3,4-thiadiazoles derivatives: synthesis, antiproliferative activity, molecular docking and molecular dynamics.

Aim: A series of 1,3,4-thiadiazole himachalene hybrids were prepared from the treatment of a himachalen-4-one thiosemicarbazone derivative with N-aryl-C-ethoxycarbonyl-nitrilimines and diarylnitrilimines via a 1,3-dipolar cycloaddition reaction. Materials & methods: The structures were confirmed by NMR, IR and high-resolution mass spectroscopy (HRMS). Results & conclusion: The newly synthesized hybrid compounds were tested for their in vitro antitumor activities against a panel of cancer cell lines including fibrosarcoma (HT-1080), lung carcinoma (A-549) and breast carcinoma (MCF-7 and MDA-MB-231). Among the tested products, 4a showed excellent activity against the HT-1080 and MCF-7 cell lines with IC50 values of 11.18 ± 0.69 and 12.38 ± 0.63 µm, comparable to that of the reference drug. Docking results confirmed that the active inhibitors were well accumulated in the mushroom tyrosinase active site. Flow cytometry analysis indicated that hybrid 4a induced apoptosis and cell cycle arrest in the G0/G1 phase. Molecular modeling studies affirmed the intercalative binding of compound 4a in the active site.

Novel Hydrazono-2-Iminothiazolidin-4-Ones Based on a Monoterpenic Skeleton as Potential Antitumor Agents: Synthesis, DFT Studies, in†Vitro Cytotoxicity, Apoptosis Inducing Properties and Molecular Docking.

A series of novel 2-iminothiazolidin-4-one analogs have been synthesized from limonaketone, and structurally characterized by HR-MS, 1 H-NMR and 13 C-NMR spectroscopy techniques, and the structure of compound 4 was elucidated by XRD. The newly synthesized products were biologically evaluated in vitro for their cytotoxic activity against human cancer cell lines HT-1080, A549, and MCF-7. Thiazolidinones 9 and 10 were the most active compounds in HT-1080 cell lines (IC50 =15.85±1.75 and 16.13±1.55 µM, respectively). The apoptosis induction of the derivatives 9 and 10 were studied using annexin V staining, caspase-3/7 activity and cell cycle analysis. Compound 10 showed the highest ability of apoptosis induction and caspase-3/7 activation associated with S-phase growth arrest in HT-1080. Meanwhile, compound 9 has a moderate apoptotic effect and G0/G1-phase arrest in the after-mentioned cell. The molecular docking suggested that compounds 9 and 10 formed stable ligand-caspase-3 complexes. Besides, the presence of phenyl moiety in ligand 10 is responsible for the enhancement of the caspase-3 activation by the apparition of two additional hydrogen bonds with Cys163 and Gln161amino acids.

Novel isoxazoline-linked 1,3,4-thiadiazole hybrids as anticancer agents: Design, synthesis, biological evaluation, molecular docking, and molecular dynamics simulation.

In the current study, natural (R)-carvone was utilized as a starting material for the efficient synthesis of two series of isoxazoline derivatives bearing the 1,3,4-thiadiazole moiety. The new compounds were obtained in good yields and were characterized by 1 H and 13 C NMR and HRMS analysis. The newly synthesized monoterpenic isoxazoline 1,3,4-thiadiazole and their thiosemicarbazone intermediate derivatives were evaluated for their anticancer activity in four cancer cell lines (HT-1080, A-549, MCF-7, and MDA-MB-231). Most of the synthesized compounds exhibited moderate to high anticancer effects. Compound 13c showed the highest anticancer activity with IC50 values ranging from 19.33 ± 1.81 to 34.81 ± 3.03 µM. Further investigation revealed that compounds 12e and 13c could inhibit the cell growth of HT-1080 and MCF-7 cells by inducing apoptosis through caspase-3/7 activation. The apoptotic effect was accompanied by an S phase and G2/M cell cycle arrest for 13c and 12e, respectively. Compounds 12e and 13c were assessed in silico using molecular docking and molecular dynamics. We found that compound 13c is moderately active against the caspase-3 protein, which triggers apoptosis via intrinsic and extrinsic routes, making compound 13c a promising candidate to activate the proapoptotic protein (caspase-3).

Design, synthesis, evaluation of new 3-acetylisoxazolines and their hybrid analogous as anticancer agents: In vitro and in silico analysis.

3-Acetylisoxazolines were synthesized by the reaction of natural (R)-limonene and (R)-carvone with acetone in the presence of iron (III) nitrate. The reaction showed to be highly peri- and regioselective. Next, using a 1,3-dipolar cycloaddition reaction, the mono-3-acylisoxazolines derived from these monoterpenes were evaluated for their reactivity with nitrilimines. Only the enone of carvone-isoxazoline was regioselectively reactive, providing a new fused isoxazoline-carvone-pyrazolines. The structure of all the newly synthesized mono-cycloadducts (3 & 5) and bis-cycloadducts (4 & 7a-c) were fully identified based on their HRMS and NMR spectral data. They have also been screened for their cytotoxic activity against four human cancer cell lines: fibrosarcoma (HT-1080), lung carcinoma (A-549), and breast (MCF-7 and MDA-MB-231) cell lines. The obtained results showed that compound 4 was a potent cytotoxic agent against all selected cells. The possible mechanism of apoptosis induction by compound 4 was investigated using Annexin-V binding assay, caspase-3/7 activity and analysis cell cycle progression. The compound 4 induced the early apoptosis of both MCF-7 and MDA-MB-231 through caspase-3/7 activation, and the compound 4 have elicited S and G2/M phase arrest in MCF-7and MDA-MB-231 cancer cells, respectively. For further target investigations, a molecular docking study was employed and it showed that compound 4 has an inhibitory activity against Pim-1 protein kinase. Molecular dynamics study showed that compound 4/Pim-1 complex was stable during the simulation run at different time intervals. In-Silico ADMET predicted that compound 4 has good pharmacokinetic properties with high estimated oral bioavailability.

New 1,2,3-Triazoles from (R)-Carvone: Synthesis, DFT Mechanistic Study and In Vitro Cytotoxic Evaluation.

Aseries of novel 1,4-disubstituted 1,2,3-triazoles were synthesized from an (R)-carvone terminal alkyne derivative via a Cu (I)-catalyzed azide-alkyne cycloaddition reaction using CuSO4,5H2O as the copper (II) source and sodium ascorbate as a reducing agent which reduces Cu (II) into Cu (I). All the newly synthesized 1,2,3-triazoles 9a-h were fully identified on the basis of their HRMS and NMR spectral data and then evaluated for their cell growth inhibition potential by MTS assay against HT-1080 fibrosarcoma, A-549 lung carcinoma, and two breast adenocarcinoma (MCF-7 and MDA-MB-231) cell lines. Compound 9d showed notable cytotoxic effects against the HT-1080 and MCF-7 cells with IC50 values of 25.77 and 27.89 µM, respectively, while compound 9c displayed significant activity against MCF-7 cells with an IC50 value of 25.03 µM. Density functional calculations at the B3LYP/6-31G* level of theory were used to confirm the high reactivity of the terminal alkyne as a dipolarophile. Quantum calculations were also used to investigate the mechanism of both the uncatalyzed and copper (I)-catalyzed azide-alkyne cycloaddition reaction (CuAAC). The catalyzed reaction gives complete regioselectivity via a stepwise mechanism streamlining experimental observations. The calculated free-energy barriers 4.33 kcal/mol and 29.35 kcal/mol for the 1,4- and 1,5-regioisomers, respectively, explain the marked regioselectivity of the CuAAC reaction.

Investigating novel thiazolyl-indazole derivatives as scaffolds for SARS-CoV-2 MPro inhibitors.

COVID-19 is a global pandemic caused by infection with the SARS-CoV-2 virus. Remdesivir, a SARS-CoV-2 RNA polymerase inhibitor, is the only drug to have received widespread approval for treatment of COVID-19. The SARS-CoV-2 main protease enzyme (MPro), essential for viral replication and transcription, remains an active target in the search for new treatments. In this study, the ability of novel thiazolyl-indazole derivatives to inhibit MPro is evaluated. These compounds were synthesized via the heterocyclization of phenacyl bromide with (R)-carvone, (R)-pulegone and (R)-menthone thiosemicarbazones. The binding affinity and binding interactions of each compound were evaluated through Schrödinger Glide docking, AMBER molecular dynamics simulations, and MM-GBSA free energy estimation, and these results were compared with similar calculations of MPro binding various 5-mer substrates (VKLQA, VKLQS, VKLQG) and a previously identified MPro tight-binder X77. From these simulations, we can see that binding is driven by residue specific interactions such as π-stacking with His41, and S/π interactions with Met49 and Met165. The compounds were also experimentally evaluated in a MPro biochemical assay and the most potent compound containing a phenylthiazole moiety inhibited protease activity with an IC50 of 92.9 â€‹µM. This suggests that the phenylthiazole scaffold is a promising candidate for the development of future MPro inhibitors.

Newly synthesized (R)-carvone-derived 1,2,3-triazoles: structural, mechanistic, cytotoxic and molecular docking studies.

In the current study, natural (R)-carvone was used as starting material for the efficient synthesis of several 1,2,3-triazole derivatives. The produced products were obtained in good yields and characterized by 1H and 13C NMR and HRMS analysis. The newly synthesized monoterpenic 1,2,3-triazole 4 and derivatives were analyzed by viability tests (MTT) for their cytotoxic activity against three human cancer cells. Product 5 showed a medium antitumor activity, for which the IC50 values against selected cells HT-1080, A-549 and MCF-7 were 29.25 µM, 31.62 µM and 26.02 µM, respectively. The regioselectivity of the condensation reaction and the molecular structure of the title compounds were determined by Density Functional Theory (DFT) using B3LYP calculations at 6-311 + G(d,p) level. The orbitals HOMO and LUMO were studied to determine the electronic properties of the synthesized compounds. In addition, the global reactivity indices were used to explain the regioselectivity for the formation of compound 6, and the theoretical results agree well with the experimental results. Molecular docking and molecular dynamics confirmed the empirical test results and confirmed the stability of the complex during inhibition of the anti-apoptotic protein for killing cancer cells. Communicated by Ramaswamy H. Sarma.

New bis-isoxazole with monoterpenic skeleton: regioselective synthesis, spectroscopic investigation, electrochemical, and density functional theory (DFT) studies.

A novel bis-isoxazole was synthesized from (R)-Carvone and p-methylbenzaldoxime, via two successive [3+2] cycloaddition reactions (32CA). The newly obtained bis-isoxazole has been fully characterized by HRMS and NMR spectroscopy. The HMBC experiment was performed to determine the stereo and the regioselectivity of the reaction. The electrochemical behavior of the studied compound, in oxidation and reduction processes, was examined using the cyclic voltammetry technique. In addition, the regioselectivity of the [3+2] cycloaddition reaction and the molecular structure of the title compound was performed by density functional theory (DFT). The HOMO and LUMO orbitals were investigated to determine the electronic properties of the synthesized compound. Besides, the global reactivity indexes were used to explain the regioselectivity for the formation of the bis-isoxazole, the theoretical results are in good agreement with experimental findings.

Thiazolidinone-linked1,2,3-triazoles with monoterpenic skeleton as new potential anticancer agents: Design, synthesis and molecular docking studies.

A novel series of 1,2,3-triazole-thiazolidinone-carvone hybrid compounds has been designed and synthesized using the copper-catalyzed Huisgen azide-alkyne 1,3-dipolar cycloaddition (CuAAC) process based on (R)-Carvone-O-propargylated 5-hydroxybenzylidene-thiazolidin-4-one derivative as starting material. All compounds were characterized and identified based on their NMR and HRMS spectroscopic data. HMBC correlations confirm that under the CuAAC reaction conditions, only the 1,4-disubstituted triazole regioisomers were formed. The targeted 1,2,3-triazole-thiazolidinone-carvone hybrids and their precursors were evaluated for their cytotoxic activity against four human cancer cell lines, including fibrosarcoma (HT-1080), lung carcinoma (A-549), and breast carcinoma (MCF-7 and MDA-MB-231). The obtained data showed that most of these compounds have moderate anti-proliferative activity with IC50 values between 15.04 ± 0.71 and 42.22 ± 1.20 µM. The mechanism of action of the most active compounds 14e and 14f suggested that they induce apoptosis through caspase-3/7 activation, and the compound 14e elicited S-phase arrest, while compound 14f evoked G2/M phase blockade. The molecular docking confirmed that compounds 14e and 14f were nicely bonded with caspace-3 leading up to stable protein-ligand complexes.

Design, Hemiysnthesis, crystal structure and anticancer activity of 1, 2, 3-triazoles derivatives of totarol.

A new series of diverse triazoles linked to the hydroxyl group of totarol were synthesized using click chemistry approach. The structures of these compounds were elucidated by HRMS, IR and NMR spectroscopy. The structure of compound 3 g was also confirmed by x-ray single crystal diffraction. The cytotoxicity of these compounds was evaluated by the MTT method against four cancer cell lines, including fibrosarcoma HT-1080, lung carcinoma A-549 and breast adenocarcinoma (MDA-MB-231 and MCF-7), and the results indicated that all compounds showed weak to moderate activities against all cancer cell lines with IC50 values ranging from 14.44 to 46.25 µM. On the basis of our research the structure-activity relationships (SAR) of these compounds were discussed. This work provides some important hints for further structural modification of totarol towards developing novel and highly effective anticancer drugs respectively. It is interesting to note that compound 3 g indicated a very significant cytotoxicity against HT-1080 and A-549 cell lines. The molecular docking showed that compound 3 g activated the caspase-3 and inhibited tubulin by forming stable protein-ligand complexes.

Crystal structure of (R)-5-[(R)-3-(4-chloro-phen-yl)-5-methyl-4,5-di-hydro-isoxazol-5-yl]-2-methyl-cyclo-hex-2-enone.

The title compound, C17H18ClNO2, was prepared and isolated as a pure diastereoisomer, using column chromatography followed by a succession of fractional crystallizations. Its exact structure was fully identified via 1H NMR and confirmed by X-ray diffraction. It is built up from a central five-membered di-hydro-isoxazole ring to which a p-chloro-phenyl group and a cyclo-hex-2-enone ring are attached in the 3 and 5 positions. The cyclo-hex-2-one and isoxazoline rings each exhibit an envelope conformation. The crystal packing features C-H⋯O, C-H⋯N and C-H⋯π inter-actions, which generate a three-dimensional network.

Hemisynthesis, crystal structure and inhibitory effect of sesquiterpenic thiosemicarbazones and thiazolidin-4-ones on the corrosion behaviour of stainless steel in 1†M H2SO4 solution.

Treatment of thiosemicarbazones prepared from sesquiterpenes with ethyl 2-bromoacetate in the presence of sodium acetate afforded the corresponding thiazolidin-4-ones. The structures of all the newly synthesized compounds were established by considering spectral and single-crystal X-ray diffraction data. The title compound, ethyl 2-((Z)-2-{(Z)-[(1aR,5aR,9aS)-1,1-dichloro-1a,5,5,7-tetramethyl-1a,2,3,4,5,5a,8,9-octahydro-1H-benzo[a]cyclopropa[b][7]annulen-8-ylidene]hydrazono}-4-oxothiazolidin-3-yl)acetate, C23H31Cl2N3O3S, 5, crystallizes in the orthorhombic noncentrosymmetric space group P212121 with Z = 4. Within the molecule in the crystal structure, the cyclohexene ring has an envelope conformation and the cycloheptane ring, to which it is fused, has a boat conformation. In the crystal, molecules are linked by C-H...Cl hydrogen bonds forming chains propagating along the b-axis direction. The absolute configuration of the molecule in the crystal could be fully confirmed from anomalous dispersion effects [Flack parameter = -0.04 (2)]. Thiosemicarbazones 1 and 2 are efficient inhibitors for steel corrosion in 1 M H2SO4 solution, with a maximum efficiency of 92.28% at 10-3 M. Furthermore, thiosemicarbazone compounds were found to be more efficient than thiazolidin-4-one derivatives. In addition, cyclic voltammetry was used to characterize the tested molecules, as well to estimate the experimental value of the energy band gap.

New polysubstituted monoterpenic thiazolidinones: synthesis, spectroscopic and crystal structure studies.

The synthesis of three new polysubstituted monoterpenic thiazolidin-4-ones, namely (Z)-3-methyl-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C14H21N3OS (2), (2Z,5Z)-5-[(dimethylamino)methylidene]-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C16H24N4OS (3), and (2Z,5Z)-5-[(dimethylamino)methylidene]-3-methyl-2-{(E)-[(1R,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene]hydrazinylidene}thiazolidin-4-one, C17H26N4OS (4), is reported, starting from the corresponding thiosemicarbazones obtained from naturally occurring (R)-camphor. All the newly obtained thiazolidin-4-ones have been fully characterized by HRMS and 1H and 13C (1D and 2D) NMR spectroscopy. Two of them, i.e. 2 and 3, were identified by single-crystal X-ray crystallography, confirming the synthetic pathway and the spectroscopic analyses. In 3, there are two roughly identical molecules within the asymmetric unit with the same absolute configuration. These two molecules are linked through N-H...O hydrogen bonds, building an R22(8) graph-set motif.