One-Pot Sequential [3 + 3] Dipolar Cycloaddition of Aldehyde or Ketone and Hydroxylamine with Spirocyclopropyl Oxindole.

A Sc(OTf)3-catalyzed highly diastereoselective one-pot sequential [3 + 3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine, and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxindole-tetrahydro-1,2-oxazines with sufficient structural diversity. The corresponding catalytic enantioselective one-pot protocol of aldehydes is also reported, affording the desired adducts in up to 97% ee. The biological evaluation of selected oxindole-based spirocyclic tetrahydro-1,2-oxazines revealed that they exerted cytotoxic effects on human prostate cancer cells with the capacity to inhibit NFκB signaling in prostate cancer cells.

Rauwolfia vomitoria extract suppresses benign prostatic hyperplasia by reducing expression of androgen receptor and 5α-reductase in a rat model.

OBJECTIVE: Herbal medicine is an important therapeutic option for benign prostatic hyperplasia (BPH), a common disease in older men that can seriously affect their quality of life. Currently, it is crucial to develop agents with strong efficacy and few side effects. Herein we investigated the effects of the extract of Rauwolfia vomitoria, a shrub grown in West Africa, on BPH. METHODS: Rats with testosterone-induced BPH were treated with R. vomitoria. Prostates were histologically analyzed by Hematoxylin and eosin staining. Proliferation index and the expression levels of androgen receptor and its associated proteins were quantified through immunohistochemistry and immunoblotting. Androgen receptor target genes were examined by quantitative real-time polymerase chain reaction. The sperm count and body weight of rats were also measured. RESULTS: The oral administration of R. vomitoria extract significantly reduced the prostate weight and prostate weight index in BPH rats, supported by the decreased thickness of the prostate epithelial layer and increased lumen size. Similar effects were observed in the BPH rats treated with the reference drug, finasteride. R. vomitoria extract significantly reduced the testosterone-induced proliferation markers, including proliferating cell nuclear antigen and cyclin D1, in the prostate glands of BPH rats; it also reduced levels of androgen receptor, its associated protein steroid 5α-reductase 1 and its downstream target genes (FK506-binding protein 5 and matrix metalloproteinase 2). Notably, compared with the finasteride group, R. vomitoria extract did not significantly reduce sperm count. CONCLUSION: R. vomitoria suppresses testosterone-induced BPH development. Due to its milder side effects, R. vomitoria could be a promising therapeutic agent for BPH.

Diastereo- and enantioselective [3 + 3] cycloaddition of spirocyclopropyl oxindoles using both aldonitrones and ketonitrones.

Optically active spirocyclic compounds play an important role in drug discovery, and new synthetic strategies for the efficient generation of spiro stereocenters are in much demand. Here we report a catalytic enantioselective cycloaddition using spirocyclic donor-acceptor cyclopropanes as a promising approach for the generation of spiro stereocenters. A diastereo- and enantioselective [3 + 3] cycloaddition of spirocyclopropyl oxindoles with both aldonitrones and ketonitrones is developed. The key to reaction development is the activation of spirocyclopropyl oxindoles by a suitable electron-withdrawing N-protecting group. This activation approach offers the promise of a general solution to enable spirocyclopropyl oxindoles as synthons for catalytic enantioselective synthesis of spirocyclic oxindoles featuring a C3 spiro stereocenter, a prominent structural motif in drugs and pharmaceutically active compounds. This protocol also constitutes the catalytic enantioselective reaction using unactivated achiral ketonitrones to construct tetrasubstituted carbon stereocenters.