Facile synthesis of phthalidyl fused spiro thiohydantoins through silica sulfuric acid induced oxidative rearrangement of ninhydrin adducts of thioureas

Moisture-Assisted Hydroboration of Nitriles and Conversion Thereof to N-Heterocyles and N-Containing Derivatives

The recent revelation of hidden-borane catalysis has revolutionized the field of catalytic hydroboration in organic synthesis. Many nucleophilic reaction promoters, previously believed to be the catalysts, in fact primarily facilitated the formation of borane (BH3), which subsequently acted as the true catalyst. This revelation prompted us to explore the untapped potential of these unexpected transformations, with a view to simplify hydroboration using more cost-effective and environmentally friendly nucleophilic precatalysts. Via computational studies, we were able to identify that water can actually undertake that role. Herein, we report a study on the simple hydroboration of nitriles, a notoriously challenging yet synthetically valuable class of substrates, using nothing more than moisture as an activating agent. This moisture-assisted nitrile hydroboration process can seamlessly integrate with a range of downstream transformations in a one-pot fashion to produce valuable N-containing products such as symmetrical imines, thioureas, and bis(alcohol)amines as well as N-heterocycles such as pyrroles, pyridines, pyridinium salts, 2-iminothiazolines, and carbazoles.

Novel imino-thiazoloquinoxaline derivatives against renal cell carcinoma: less radiation-damaging approach

Renal cell carcinoma (RCC) is the most fatal tumor in the urinary system. Resistance development and unmet effective responses, request new anticancer agents with better therapeutic index. Ten new imino-thiazolo-quinoxaline derivatives (5a-j) were synthesized and preliminary evaluated for downregulation of Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) activity taking sorafenib as a reference drug. Compounds 5d & 5h showed potent inhibition to VEGFR-2 activity at IC50 89.35 nM & 60.64 nM, respectively, then they both were further evaluated in-vitro against urinary bladder cancer cell line T-24 taking sorafenib as a reference drug. Compound 5h displayed nearly anticancer activity to sorafenib against T-24 cell line in all concentrations tested except at concentration 10 µM where it highly suppressed cell viability to 6.71 % compared to 15.15% of sorafenib. Compound 5h was then evaluated for its ameliorative efect against radiation induced renal tissue injury. Assessment of pro-angiogenic (VEGFR-2), pro-fibrotic (transforming growth factor-beta 1 (TGF-β1)) and apoptotic (caspase-3) markers, as well as histopathological examinations were performed on kidney of irradiated mice. Results showed ability of compound 5h to downregulate VEGFR-2 activity and its cytotoxic effect against RCC, in addition to mitigation of radiation induced renal tissue injury. Ethyl imino-thiazoloquinoxaline carboxylate derivative 5h showed a potential cytotoxic activity against RCC and could be considered a promosing alleviative candidate when employed post radiotherapy regimen.

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Silica–sulfuric acid and alumina–sulfuric acid: versatile supported Brønsted acid catalysts

–SO3H functionalized silica and alumina have emerged as efficient and eco-compatible heterogeneous solid acid catalysts for the construction of various important molecular skeletons.