Synthesis of bioactive spiro-2-[3′-(2′-phenyl)-3H-indolyl]-1-aryl-3-phenylaziridines and SAR studies on their antimicrobial behavior

Spiro-β-lactam BSS-730A Displays Potent Activity against HIV and Plasmodium

The high burden of malaria and HIV/AIDS prevents economic and social progress in developing countries. A continuing need exists for development of novel drugs and treatment regimens for both diseases in order to address the tolerability and long-term safety concerns associated with current treatment options and the emergence of drug resistance. We describe new spiro-β-lactam derivatives with potent (nM) activity against HIV and Plasmodium and no activity against bacteria and yeast. The best performing molecule of the series, BSS-730A, inhibited both HIV-1 and HIV-2 replication with an IC₅₀ of 13 ± 9.59 nM and P. berghei hepatic infection with an IC₅₀ of 0.55 ± 0.14 μM with a clear impact on parasite development. BSS-730A was also active against the erythrocytic stages of P. falciparum, with an estimated IC₅₀ of 0.43 ± 0.04 μM. Time-of-addition studies showed that BSS-730A potentially affects all stages of the HIV replicative cycle, suggesting a complex mechanism of action. BSS-730A was active against multidrug-resistant HIV isolates, with a median 2.4-fold higher IC₅₀ relative to control isolates. BSS-730A was equally active against R5 and X4 HIV isolates and displayed strong synergism with the entry inhibitor AMD3100. BSS-730A is a promising candidate for development as a potential therapeutic and/or prophylactic agent against HIV and Plasmodium.

Design, Construction, and Characterization of a New Regioisomer and Diastereomer Material Based on the Spirooxindole Scaffold Incorporating a Sulphone Function

The 1,3-dipolar cycloaddition reaction is one of the most rapid, and efficient protocols to access, and construct highly divergent heterocycle chiral auxiliaries. Free catalyst synthesis of spirooxindole scaffold incorporating sulphone moiety via one pot–three component reaction of 6-chloro-isatin, L-proline, and the phenylvinylsulphone as dienophile is presented. The new regioisomer and diastereomer was isolated by precipitation without the tedious purification step, and then characterized via NMR and single crystal X-ray diffraction analysis. Using Hirshfeld analysis, the analysis of molecular packing was performed. It depended mainly on strong O…H and N…H interactions, and weak H…H, C…H, and Cl…H interactions as well. DFT calculations were used to optimize the experimental X-ray structure, which was found well matched with the calculated one. Reactivity descriptors based on the energies of the highest occupied (HOMO) and lowest unoccupied (LUMO) molecular orbitals were calculated. Additionally, the donor–acceptor interactions which stabilized the system via σ–σ*, π→π*, n→σ* and n→π* electron delocalization processes were also computed using NBO calculations. The net interaction energies are 49.96, 235.38, 179.66 and 107.06 kJ/mol, respectively. Additionally, the calculated NMR chemical shifts correlated well with the experimental data (R2=0.99).

Synthesis, Anticancer Activity, and Molecular Modeling of New Halogenated Spiro[pyrrolidine-thiazolo-oxindoles] Derivatives

A one-pot, single-step, and an atom-economical process towards the synthesis of highly functionalized spirooxindoles analogues was efficiently conducted to produce a satisfactory chemical yields (70–93%) with excellent relative diastereo-, and regio-selectivity. An in vitro antiproliferative assay was carried out on different cancer cell lines to evaluate the biological activity of the synthesized tetrahydro-1’H-spiro[indoline-3,5’-pyrrolo[1,2-c]thiazol]-2-one 5a–n. The prepared hybrids were then tested in vitro for their antiproliferative effects against three cancer cell lines, namely, HepG2 (liver cancer), MCF-7 (breast cancer), and HCT-116 (colon cancer). The spirooxindole analogue 5g exhibited a broad activity against HepG2, MCF-7, and HCT-116 cell lines of liver, breast, and colorectal cancers when compared to cisplatin. Modeling studies including shape similarity, lipophilicity scores, and physicochemical parameters were calculated. The results of this study indicated that spirooxindole analogue 5g retained a good physiochemical parameters with acceptable lipophilicity scores.

Nickel-Catalyzed C(2)-H Arylation of Indoles with Aryl Chlorides under Neat Conditions

Nickel-catalyzed regioselective C(2)-H arylation of indoles and pyrroles with aryl chlorides is achieved under neat conditions. This method allows the efficient coupling of diverse aryl chlorides employing a user-friendly and inexpensive Ni(OAc)₂/dppf catalyst system at 80 °C. Numerous functionalities, such as halides, alkyl ether, fluoro-alkyl ether, and thioether, and substituted amines, including heteroarenes like benzothiazolyl, pyrrolyl, indolyl, and carbazolyl, are well tolerated under the reaction conditions. The preliminary mechanistic study highlights a single-electron transfer (SET) pathway for the arylation reaction.

A One-Pot Ring-Opening/Ring-Closure Sequence for the Synthesis of Polycyclic Spirooxindoles

One-pot ring-opening/ring-closure process of combining methyleneindolinone with 3-aminooxindole has been developed in this work. Novel polycyclic spirooxindoles were efficiently assembled under mild conditions in high yields (up to 95 %) with moderate to good diastereoselectivities (up to >95:5 d.r.) through simple filtration.

Dearomatizing Spiroannulation Reagents: Direct Access to Spirocycles from Indoles and Dihalides

Unfunctionalized indoles can be directly converted into 3,3'-spirocyclic indolenines and indolines upon reaction with electrophilic dihalides in the presence of t-BuOK/BEt₃. This double C-C bond forming reaction, which simultaneously generates a quaternary spirocyclic center, typically proceeds in high yield and has good functional group tolerance. In contrast to existing dearomatizing spirocyclization approaches, there is no need to prepare a prefunctionalized aromatic precursor, enabling faster access to valuable spirocyclic products from simple, commercially available aromatics in one step.

Biomedical importance of indoles

The indole nucleus is an important element of many natural and synthetic molecules with significant biological activity. This review covers some of the relevant and recent achievements in the biological, chemical and pharmacological activity of important indole derivatives in the areas of drug discovery and analysis.