Palladium-Catalyzed Skeletal Rearrangement of Substituted 2-Silylaryl Triflates via 1,5-C-Pd/C-Si Bond Exchange.

A palladium-catalyzed skeletal rearrangement of 2-(2-allylarylsilyl)aryl triflates has been developed to give highly fused tetrahydrophenanthrosilole derivatives via unprecedented 1,5-C-Pd/C-Si bond exchange. The reaction pathways can be switched toward 4-membered ring-forming C(sp2 )-H alkylation by tuning the reaction conditions to give completely different products, fused dihydrodibenzosilepin derivatives, from the same starting materials. The inspection of the reaction conditions revealed the importance of carboxylates in promoting the C-Pd/C-Si bond exchange.

Palladium-catalyzed synthesis of benzosilacyclobutenes via position-selective C(sp3)-H arylation.

A palladium-catalyzed synthesis of benzosilacyclobutenes has been developed via position-selective C(sp3)-H bond activation, including those having substituents at the methylene carbon on the 4-membered silacycle. The obtained products could be engaged in the palladium- or nickel-catalyzed ring-expansion reactions to give compounds possessing 6-membered silacycles.

85-year-old woman • insomnia • abdominal discomfort • urge to move at night • Dx?

►insomnia ► abdominal discomfort ► urge to move at night.

Heterogeneous interaction network of yeast prions and remodeling factors detected in live cells.

Budding yeast has dozens of prions, which are mutually dependent on each other for the de novo prion formation. In addition to the interactions among prions, transmissions of prions are strictly dependent on two chaperone systems: the Hsp104 and the Hsp70/Hsp40 (J-protein) systems, both of which cooperatively remodel the prion aggregates to ensure the multiplication of prion entities. Since it has been postulated that prions and the remodeling factors constitute complex networks in cells, a quantitative approach to describe the interactions in live cells would be required. Here, the researchers applied dual-color fluorescence cross-correlation spectroscopy to investigate the molecular network of interaction in single live cells. The findings demonstrate that yeast prions and remodeling factors constitute a network through heterogeneous protein-protein interactions. [BMB Reports 2017; 50(9): 478-483].

Synthesis and ABCG2 inhibitory evaluation of 5-N-acetylardeemin derivatives.

An efficient and versatile synthesis of 5-N-acetylardeemin (1a) and sixteen 2-, 3- and 13-substituted derivatives 1b-q was achieved through Ugi three-component reaction of 3,3a,8,8a-tetrahydropyrrolo[2,3-b]indole and cyclization/epimerization. Their inhibitory activity on the drug efflux of breast cancer resistance protein (ABCG2) was evaluated by flow cytometric analysis of accumulation of Hoechst 33342 stain in Flp-In-293/ABCG2 cells. Most of the derivatives exhibited a stronger ABCG2 inhibitory effect compared with natural product 1a. The derivative 1m with a 4-tolyl substituent at the C-13 position exhibited the most potent ABCG2 inhibition. This preliminary structure-activity relationship study indicates that an electron-rich aryl moiety as the 13-substituent is key to increasing the inhibitory activity.

[Tuberculous cranial pachymeningitis presenting with long-standing diffuse brain dysfunction].

We report a 59-year-old immunocompetent man presenting with slowly progressive gait unsteadiness, dysarthria, and clumsiness in writing over 6 months. There were bilateral pyramidal signs, pseudobulbar palsy, and attention deficits. Cerebrospinal fluid examination showed mild mononuclear pleocytosis, and magnetic resonance imaging revealed pachymeningeal pattern of contrast enhancement beneath the calvarium and the posterior cranial fossa. Interferon-gamma release assay in whole blood after stimulation by specific tuberculosis antigens was positive and repeat polymerase chain reaction assay detected Mycobacterium tuberculosis genome in the cerebrospinal fluid. After combination therapy with anti-tuberculous agents and corticosteroids, the patient's pachymeningitis regressed. Tuberculous cranial pachymeningitis may present with chronic diffuse brain dysfunction without headache, fever, or cranial nerve dysfunction.

[A 25-year-old woman with primary Sjögren syndrome who developed optic neuritis and encephalomyelitis associated with an anti-aquaporin 4 antibody].

We report a 25-year-old woman who developed optic neuritis and encephalomyelitis following primary Sjögren's syndrome (SjS). SjS began with Sicca syndrome when she was 8 years old, and neurological involvement subsequently developed at the age of 10 with right hemiparesis. Based on clinical symptoms, serum positive for SS-A and SS-B antibodies and pathological findings of the salivary gland, we confirmed a diagnosis of primary SjS. Magnetic resonance imaging (MRI) revealed multiple lesions in the brain and the spinal cord. These led diagnosis of SjS with central nervous system involvement (CNS-SjS) and initiated steroid therapy. At the age of 25, the patient developed left visual loss due to retrobulbar optic neuritis, left lower quadrantic hemianopia, numbness of the right upper limb, and weakness of both legs. Laboratory examinations showed that her serum was positive for SS-A and SS-B antibodies, and her cerebrospinal fluid had elevated levels of total protein and myelin basic protein without pleocytosis. Her brain MRI revealed multiple T2-high-intensity lesions bilaterally in the frontal subcortical white matter and in the right temporo-parietal subcortical white matter. The lesions included a tumefactive lesion and an active lesion. Additionally, the spinal MRI revealed a severely atrophied spinal cord with T2-high-intensity lesions extending longitudinally and centromedullary in the spinal cord. These findings led us to examine the patient's serum for anti-aquaporin (AQP) 4 antibodies and the test confirmed that her serum was positive for the antibodies. After administering intravenous high-dose methylprednisolone (1,000 mg/day for 3 days), her symptoms markedly improved with normalization of myelin basic protein. However, her serum remained positive for AQP 4 antibodies. We think that the patient's diagnosis belongs to the neuromyelitis optica (NMO) spectrum disorders associated with autoimmune disorders. This is a rare case in that the initial presentation was SjS and occurred at a very young age.