Androgen receptor antagonists and anti-prostate cancer activities of some newly synthesized substituted fused pyrazolo-, triazolo- and thiazolo-pyrimidine derivatives

Biological Evaluation of Anti-Cholinesterase Activity, in Silico Molecular Docking Studies, and DFT Calculations of Green Synthesized Thiadiazolo[3,2-a]pyrimidine Derivatives

A series of [1,3,4] thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives 4(a-n) have been designed and synthesized as inhibitors of acetylcholinesterase (AChE). Synthesizing of thiadiazolo[3,2-a] pyrimidines was carried out in a single step, one-pot reaction using aromatic aldehydes, ethyl acetoacetate and different derivatives of 1,3,4-thiadiazoles (with molar ratio of 1 : 2 : 1, respectively) in conjunction with the catalyst, anhydrous iron(III) chloride by a grinding method under solvent-free conditions at room temperature. The in-vitro studies exhibited good potency for inhibiting AChE comparable with donepezil as the reference drug. The best results were obtained by Ethyl 2-(4-nitroophenyl)-7-methyl-5-(pyridin-3-yl)-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate 4n with IC50 value of 0.082±0.001 μM which was comparable with AChE inhibitory effects of donepezil (IC50 =0.079 μM).

Access and modulation of substituted 1-methyl-1,6-dihydropyrazolo[3,4-c]pyrazoles

Despite the pharmacological potential of the pyrazolo[3,4-c]pyrazoles, only a few methods of preparation and direct functionalization of this moiety have been described. We report herein a convenient design of new pyrazolo[3,4-c]pyrazoles with a high therapeutic impact. The effective chosen strategy consists of hydrazine condensations and C–N Ullmann-type cross-coupling reactions with microwave activation. Moreover, chemoselective bromination of the newly formed bipyrazoles followed by Suzuki–Miyaura cross-coupling reactions allowed the synthesis of a variety of modulated heterobicycles.

A convenient design of pyrazolo[3,4-c]pyrazoles is reported through hydrazine condensations and C–N Ullmann-type cross-coupling reactions. Chemoselective bromination followed by Suzuki–Miyaura cross-coupling reactions access to a variety of modulated heterobicycles.

Design, Synthesis, and Biological Evaluation of (E)-N'-((1-Chloro-3,4-Dihydronaphthalen-2-yl)Methylene)Benzohydrazide Derivatives as Anti-prostate Cancer Agents

Prostate Cancer (PCa) is the most frequently diagnosed cancer in men in their late '50s. PCa growth is mainly due to the activation of the androgen receptor by androgens. The treatment for PCa may involve surgery, hormonal therapy, and oral chemotherapeutic drugs. A structural based molecular docking approach revealed the findings of (E)-N'-((1-chloro-3,4-dihydronaphthalen-2-yl)methylene)benzohydrazide derivatives, where the possible binding modes of the compounds with protein (PDB ID: 3V49) are shown. The compounds (6a-k) were synthesized and characterized by using conventional methods. The compounds, 6g, 6j, and 6k were reconfirmed through single crystal X-ray diffraction (XRD). Further, the compounds (6a-k) and standard drug were evaluated against human prostate cancer cell lines, LNCaP and PC-3 and the non-cancerous cell line, 3T3. Among these compounds, 6g and 6j showed higher cytotoxicity, and 6g exhibited dose-dependent activity and reduced cell viability. The mechanism of action was observed through the induced apoptosis and was further confirmed by western blot and ELISA. Molecular dynamics simulation studies were carried out to calculate the interaction and the stability of the protein-ligand complex in motion. ADME properties were predicted for all the tested compounds. These findings may give vital information for further development.

Umpolung cyclization reaction of N-cinnamoylthioureas in the presence of DBU

A novel regioselective cyclization reaction of N-cinnamoylthioureas leading to six- or five-membered heterocyclic compounds was developed. N-Cinnamoylthioureas in the presence of trifluoroacetic acid (TFA) underwent the well-established intramolecular cycloaddition reaction to give 2-imino-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones in good yields. On the other hand, the reaction with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) proceeded in an unprecedented "umpolung" cyclization fashion to afford five-membered 2-imino-1,3-thiazolidin-4-ones and/or 2-thioxoimidazolidine-4-ones. The reaction was considered to occur via a cycloadduct of DBU with the cinnamoyl moiety followed by intramolecular attack of the thiourea group.

Synthesis and Antimicrobial Evaluation of a New Series of Heterocyclic Systems Bearing a Benzosuberone Scaffold

A series of novel benzosuberone derivatives were synthesized and evaluated as antimicrobial agents by using substituted benzosuberone derivatives 1a,b as starting materials. Treatment of 1a,b with phenyl isothiocyanate in dimethylformamide was followed by treatment with cold HCl solution to afford the thioamides 4a,b, which was reacted with methyl iodide to obtain methylated products 5a,b. Cyclocondensation of 4a,b with chloroacetone 6 and phenacyl chloride 7 gave the corresponding thiophene derivatives 9a-c. Reaction of 4a,b with C-acetyl-N- arylhydrazonoyl chlorides 14a and 14b in boiling EtOH in the presence of triethylamine, afforded the corresponding 1,3,4-thiadiazoline derivatives 16a-d. The thioamides 4a,b were reacted with C-ethoxycarbonyl-N-arylhydrazonoyl chlorides 18a,b which afforded 1,3,4-thiadiazoline derivatives 19a-d. The benzosuberones 1a,b were treated with 3-mercaptopropanoic acid to give compounds 21a,b, which were cyclized to tricyclic thiopyran-4(5H)-one derivatives 22a,b. The latter compounds 22a,b were reacted with 3-mercaptopropanoic acid to give compounds 23a,b, which were cyclized tetracyclic ring systems 24a,b. Finally, compounds 24a,b were oxidized using hydrogen peroxide under reflux conditions to afford the oxidized form of the novel tetracyclic heterogeneous ring systems 25a,b. The newly synthesized compounds were screened for antimicrobial activities. The structures of new compounds were characterized by ¹H-NMR, 13C-NMR, IR, and EI-MS.