3D-Printing of Capsule Devices as Compartmentalization Tools for Supported Reagents in the Search of Antiproliferative Isatins

The application of high throughput synthesis methodologies in the generation of active pharmaceutical ingredients (APIs) currently requires the use of automated and easily scalable systems, easy dispensing of supported reagents in solution phase organic synthesis (SPOS), and elimination of purification and extraction steps. The recyclability and recoverability of supported reagents and/or catalysts in a rapid and individualized manner is a challenge in the pharmaceutical industry. This objective can be achieved through a suitable compartmentalization of these pulverulent reagents in suitable devices for it. This work deals with the use of customized polypropylene permeable-capsule devices manufactured by 3D printing, using the fused deposition modeling (FDM) technique, adaptable to any type of flask or reactor. The capsules fabricated in this work were easily loaded "in one step" with polymeric reagents for use as scavengers of isocyanides in the work-up process of Ugi multicomponent reactions or as compartmentalized and reusable catalysts in copper-catalyzed cycloadditions (CuAAC) or Heck palladium catalyzed cross-coupling reactions (PCCCRs). The reaction products are different series of diversely substituted isatins, which were tested in cancerous cervical HeLa and murine 3T3 Balb fibroblast cells, obtaining potent antiproliferative activity. This work demonstrates the applicability of 3D printing in chemical processes to obtain anticancer APIs.

Design, Synthesis, and Biological Evaluation of 2-Mercaptobenzoxazole Derivatives as Potential Multi-Kinase Inhibitors

A series of 12 compounds was designed and synthesized, based on 2-mercaptobenzoxazole derivatives containing either the substituted benzenes 4a-d, substituted isatins 5a-f, or heterocycles 6a-b. The in vitro antiproliferative activity of the compounds was evaluated against hepatocellular carcinoma (HepG2), mammary gland cancer (MCF-7), breast cancer (MDA-MB-231), and the epithelioid cervix carcinoma (HeLa) cancer cell lines. Compounds 4b, 4d, 5d, and 6b had the most potent antiproliferative activity, with IC₅₀ values ranging from 2.14 to 19.34 µM, compared to the reference drugs, doxorubicin and sunitinib. Compound 6b revealed a remarkably broad antitumor activity pattern against HepG2 (IC₅₀ 6.83 µM), MCF-7 (IC₅₀ 3.64 µM), MDA-MB-231 (IC₅₀ 2.14 µM), and HeLa (IC₅₀ 5.18 µM). In addition, compound 6b showed potent inhibitory activities against EGFR, HER2, VEGFR2, and the CDK2 protein kinase enzymes, with IC₅₀ values of 0.279, 0.224, 0.565, and 0.886 µM, respectively. Moreover, compound 6b induced caspase-dependent apoptosis and cell cycle arrest at the G2/M phase. Finally, a molecular docking simulation was performed for compound 6b to predict the potential ligand-protein interactions with the active sites of the EGFR, HER2, and VEGFR2 proteins.

Synthesis and antiproliferative activity characterization of new imidazothiazolotriazine oxindolylidene derivatives containing various substituents in the oxindole ring

Condensation of 1,3-diethyltetrahydroimidazo[4,5-е]thiazolo[3,2-b][1,2,4]triazine-2,7-dione with isatins followed by framework rearrangement in the thiazolotriazine moiety was used to synthesize two new series of oxindolylidenetetrahydroimidazo[4,5-е]thiazolo- [3,2-b][1,2,4]triazine-2,7-diones and oxindolylidenetetrahydroimidazo[4,5-е]thiazolo[2,3-c][1,2,4]triazine-2,8-diones containing various substituents in the oxindole moiety. The obtained compounds were tested for antiproliferative activity. The greatest activity was observed in the case of 1-alkyl-7-methyloxindolylidene derivatives of imidazo[4,5-е]thiazolo[2,3-c]triazine, which not only inhibited the growth of more than half of the studied cell lines, but also caused cell death in the SF-539 cell line (central nervous system cancer, mean growth percent –7.82%) and MDA-MB-435 (melanoma, –30.97 and –13.64%).

Urea-Derivative Catalyzed Enantioselective Hydroxyalkylation of Hydroxyindoles with Isatins

The enantioselective transformations of indoles preferentially take place in the more-reactive azole ring. However, the methods for the enantioselective functionalization of the indole benzene ring are scarce. In this paper, a series of bifunctional (thio)urea derivatives were used to organocatalyze the enantioselective Friedel-Crafts hydroxyalkylation of indoles with isatins. The resulting products were obtained in good yields (65-90%) with up to 94% enantiomer excess (ee). The catalyst type and the substrate scope were broadened in this methodology.

Catalytic Enantioselective Ynamide Additions to Isatins: Concise Access to Oxindole Alkaloids

The highly enantioselective addition of terminal ynamides to a variety of isatins, catalyzed by a bisoxazolidine copper complex under mild, base-free reaction conditions, is described. The reaction is broad in scope, scalable, applicable to unprotected isatins, and provides efficient access to 3-hydroxyoxindoles carrying a tetrasubstituted chiral center with excellent yields and enantioselectivities. Synthetically versatile, multifunctional 3-hydroxyindolinones are obtained by hydration, partial hydrogenation, or hydroxyacyloxylation of the ynamide moiety at room temperature and exhaustive hydrogenation followed by reductive detosylation and spontaneous cyclization affords cinchonamidine alkaloids.

Urea derivative catalyzed enantioselective aldol reaction of isatins with ketones

Urea derivative has been used to catalyze the asymmetric aldol reaction of isatins with ketones. The resulting 3-alkyl-3-hydroxy-indolin-2-ones products were obtained in good yields (70%-94%) with high enantioselectivities (up to 87%ee).

Isatin-benzoazine molecular hybrids as potential antiproliferative agents: synthesis and in vitro pharmacological profiling

In continuation of our endeavor with respect to the development of potent and effective isatin-based anticancer agents, we adopted the molecular hybridization approach to design and synthesize four different sets of isatin-quinazoline (6a-f and 7a-e)/phthalazine (8a-f)/quinoxaline (9a-f) hybrids. The antiproliferative activity of the target hybrids was assessed towards HT-29 (colon), ZR-75 (breast) and A-549 (lung) human cancer cell lines. Hybrids 8b-d emerged as the most active antiproliferative congener in this study. Compound 8c induced apoptosis via increasing caspase 3/7 activity by about 5-fold in the A-549 human cancer cell line. In addition, it exhibited an increase in the G1 phase and a decrease in the S and G2/M phases in the cell cycle effect assay. Furthermore, it displayed an inhibitory concentration 50% value of 9.5 µM against multidrug-resistant NCI-H69AR lung cancer cell line. The hybrid 8c was also subjected to in vitro metabolic investigations through its incubation with rat liver microsomes and analysis of the resulting metabolites with the aid of liquid chromatography-mass spectrometry.

Enantioselective Assembly of Spirolactones through NHC-Catalyzed Remote γ-Carbon Addition of Enals with Isatins

A chiral N-heterocyclic carbene (NHC)-catalyzed formal [4 + 2] annulation of β-methyl substituted enals with isatins was developed to construct six-membered spirolactones bearing highly congested quaternary carbon stereocentersin good yields and high enantioselectivities. The strategy realized a challenging remote γ-carbon addition of enals and chiral control of β-methyl substituted enals in the presence of the NHC catalyst only.

Cross-Aldol Reaction of Isatin with Acetone Catalyzed by Leucinol: A Mechanistic Investigation

Comprehensive mechanistic studies on the enantioselective aldol reaction between isatin (1 a) and acetone, catalyzed by L-leucinol (3 a), unraveled that isatin, apart from being a substrate, also plays an active catalytic role. Conversion of the intermediate oxazolidine 4 into the reactive syn-enamine 6, catalyzed by isatin, was identified as the rate-determining step by both the calculations (ΔG(≠) =26.1 kcal mol(-1) for the analogous L-alaninol, 3 b) and the kinetic isotope effect (kH /kD =2.7 observed for the reaction using [D6 ]acetone). The subsequent reaction of the syn-enamine 6 with isatin produces (S)-2 a (calculated ΔG(≠) =11.6 kcal mol(-1) ). The calculations suggest that the overall stereochemistry is controlled by two key events: 1) the isatin-catalyzed formation of the syn-enamine 6, which is thermodynamically favored over its anti-rotamer 7 by 2.3 kcal mol(-1) ; and 2) the high preference of the syn-enamine 6 to produce (S)-2 a on reaction with isatin (1 a) rather than its enantiomer (ΔΔG(≠) =2.6 kcal mol(-1) ).

FeCl3-Catalyzed Combinatorial Synthesis of Functionalized Spiro[Indolo-3,10'-indeno [1,2-b]quinolin]-trione Derivatives

An efficient, inexpensive, environmentally friendly and high yield one-pot route to new spiro[indolo-3,10'-indeno [1,2-b]quinolin]-trione derivatives has been developed, involving three-component reaction of enaminones, N-substituted isatins and Indane-1,3-dione catalyzed by FeCl3. The approach to this spiro-heterocycle is noteworthy because it results in the formation of three new σ (two C-C and one C-N) bonds in a single operation, leading to the construction of novel spiro skeleton. This method works on a large scale in excellent yields.

Palladium(0)-catalyzed single and double isonitrile insertion: a facile synthesis of benzofurans, indoles, and isatins

A palladium(0)-catalyzed cascade process consisting of isonitrile insertion and α-Csp(3)-H cross-coupling can be achieved for the synthesis of benzofurans and indoles. The construction of isatins by a Pd-catalyzed cascade reaction incorporating double isonitrile insertion, amination, and hydrolysis has also been achieved. The key features of this work include diverse heterocycle synthesis, phosphine-ligand-free reaction conditions, a one-pot procedure, simple and commercially available starting materials, broad functional-group compatibility, and moderate to good reaction yields.

Facile creation of 3-substituted-3-hydroxy-2-oxindoles by arginine-catalyzed aldol reactions of α,β-unsaturated ketones with isatins

An efficient approach for the synthesis of 3-substituted-3-hydroxy-2-oxindoles has been achieved via an aldol reaction of α,β-unsaturated ketones and isatins using arginine as an organocatalyst. A range of 3-substituted-3-hydroxy-2-oxindoles were obtained in moderate to high (up to 99%) yields. These 3-substituted-3-hydroxy-2-oxindoles with an additional enone moiety provide an opportunity for further elaboration of the products and for potentially interesting biological activities. In addition, the formation of 3-substituted-3-hydroxy-2-oxindole 3a was confirmed by X-ray crystallography. The possible reaction mechanism reveals that the reaction proceeds via a double action process.