Polyaniline-Induced Arylation with Arenediazonium Salts Derived from Anilines.

A catalytic amount of a reduced form of polyaniline (a redox-active π-conjugated polymer) was found to induce C-H direct arylation of (hetero)arenes with arenediazonium salts prepared from anilines with methanesulfonic acid (MeSO3 H) and tert-butyl nitrite (tBuONO). The difficult part of this method is the coexistence of an oxidant and a reductant in this sequential diazotization and arylation system; diazotization requires weak oxidants such as alkyl nitrites, whereas the arylation is induced by a reductant. This was achieved by the careful control of the amount of tBuONO (1.0 equivalent) for the diazotization step, and sequential arylation using 5 mol % of the polyaniline. The reaction took place under mild conditions without any metals or strong bases at room temperature, and the amino group is a formal leaving group. The scope of the substrates demonstrates the versatility in the combination of anilines with a variety of functional groups and several (hetero)arenes. Two-directional arylation for the synthesis of an unsymmetrical 1,4-diarylated (furyl and pyrrolyl groups) benzene was achieved, using mono-Boc-protected 1,4-phenylenediamine as a substrate. This shows potential for the synthesis of more complicated oligoarene compounds.

Polyaniline-Induced C-H Arylation of Arenes with Arenediazonium Salts.

A reduced form of polyaniline has been shown to induce direct arylation of an arenediazonium salt with an arene (Gomberg-Bachmann reaction) to give the cross-coupling product in moderate to good yields under mild conditions. Various arenediazonium salts and arenes, including heteroarenes such as furans, thiophenes, and pyrroles, are employed for the reaction. The most favorable combination of substrates is an electron-poor arenediazonium salt with an electron-rich heteroarene. Investigation of the mechanism by reactions with radical scavengers and experiments on kinetic isotope effects indicated the occurrence of a radical chain reaction initiated by one-electron reduction of an arenediazonium salt by the polyaniline. Only 1 mol % (based on aniline tetramer) of the polyaniline is required for the cross-coupling reaction to occur. This reaction proceeds under metal-free conditions and with no need for photonic activation.

Synthesis of tertiary alkylphosphonate oligonucleotides through light-driven radical-polar crossover reactions.

Chemical modification of nucleotides can improve the metabolic stability and target specificity of oligonucleotide therapeutics, and alkylphosphonates have been employed as charge-neutral replacements for naturally-occurring phosphodiester backbones in these compounds. However, at present, the alkyl moieties that can be attached to phosphorus atoms in these compounds are limited to methyl groups or primary/secondary alkyls, and such alkylphosphonate moieties can degrade during oligonucleotide synthesis. The present work demonstrates the tertiary alkylation of the phosphorus atoms of phosphites bearing two 2'-deoxynuclosides. This process utilizes a carbocation generated via a light-driven radical-polar crossover mechanism. This protocol provides tertiary alkylphosphonate structures that are difficult to synthesize using existing methods. The conversion of these species to oligonucleotides having charge-neutral alkylphosphonate linkages through a phosphoramidite-based approach was also confirmed in this study.

Absence seizures with myoclonic seizures as an early manifestation of dentato-rubro-pallido-luysian atrophy (DRPLA): a follow-up clinical course of twelve years.

Typical absence seizures and isolated myoclonic seizures are both classified as age-related generalized seizures and are considered to be benign neurological manifestations. Concomitance of the two types of seizure is considered benign if it does not accompany other types of seizures or other neurological problems. We followed up a ten-year-old girl with isolated absence and myoclonic seizures whose family history of mental and neurological signs was initially not disclosed. After several years, the family history of neurological and mental problems was finally disclosed, and the diagnosis of dentato-rubro-pallido-luysian atrophy (DRPLA) was confirmed. The patient's clinical course was slowly progressive, and by age 21 she was in a nearly vegetative state. We would like to alert clinicians to consider DRPLA when diagnosing patients with absence and/or myoclonic seizures, even when they present the clinical features of benign epilepsies in the early stage.

[A case of deep cerebral venous thrombosis with sudden convulsion after delivery].

A 25-year-old woman was admitted to our hospital because of convulsions after delivering a baby. Her neurological examination revealed a disturbance of consciousness and weakness in both arms. A brain magnetic resonance imaging scan (MRI) showed thrombosis of the left transverse sinus and many patchy high signals at bilateral basal ganglia and subcortical areas. A digital subtraction angiogram (DSA) of the brain revealed a defect at the left transverse sinus, congestion of the cerebral venous flow at the vein of Galen and vasospastic changes at both posterior cerebral arteries. After treating the patient with a venous infusion of heparin, nicardipine and phenytoin, her neurological deficits improved within a day. When MRI and DSA were repeated 2 weeks later, the abnormal lesions had disappeared. These findings suggest that venous thrombosis and vasospasm had the pathogenesis of eclampsia in this case.

An autopsy case of Sjögren's syndrome with acute encephalomyelopathy.

OBJECTIVE: This study was to clarify the neuropathological findings of acute encephalomyelopathy with Sjögren's syndrome. METHODS: We examined an autopsied case of acute encephalomyelopathy with Sjögren's syndrome. CASE REPORT: A 40-year-old woman developed acute myelopathy and brainstem dysfunction. Magnetic resonance imaging (MRI) revealed high-intensity lesions on T2-weighted axial images (T2WI) in the medulla oblongata and cervical spinal cord. We established a diagnosis of Sjögren's syndrome (SjS) according to the European Community criteria. The patient was treated with intravenous methylprednisolone (500 mg/day) for three days, followed by oral prednisolone. Although her neurological symptoms improved, her general condition deteriorated after the onset of acute colonic pseudo-obstruction and she died of multiple organ failure associated with hemophagocytosis. RESULTS: Autopsy showed atrophy of the secretory glands and an accumulation of lymphocytes around the ducts, confirming the diagnosis of Sjögren's syndrome. Neuropathological examination revealed multifocal lesions in the cervical spinal cord and medulla, along with scattered perivascular lymphocytic infiltration. In addition, there was demyelination, spongy change and axonal swelling in the white matter, but no remarkable vasculitic changes were seen in the central nervous system. CONCLUSION: Although the steroid therapy may have had a significant influence, the main pathological finding in this case was not vasculitis, but rather axonal degeneration with spongy change and axonal swelling.