We have developed a new strategy for the generation of phosphenium dication equivalents from readily available phosphinic acids and Tf 2 O. The in situ-generated dication equivalents can be readily coupled with simple (hetero)biaryls to form the corresponding dibenzophospholes directly. This protocol can also be applied to the concise synthesis of six-and seven-membered phosphacycles as well as the largely π-extended heteroacene derivatives, which are of great interest in the field of organic functional materials.
A phosphenium-cation-mediated formal [3+2]-cycloaddition reaction of internal alkynes is reported. The reaction proceeds under metal-free conditions to give the corresponding C-P rearranged benzophospholes regioselectively, even when ortho- and para-substituted arylphosphine oxides are starting substrates. Mechanistic studies by P{ H} NMR analysis suggest an involvement of three-membered phosphirenium cation species and C-P rearrangement prior to a ring closure for benzophosphole skeleton formation.
A Tf2O-mediated
intramolecular phospha-Friedel–Crafts-type
reaction of secondary biarylphosphine oxides has been developed. The
reaction is promoted simply by Tf2O to form the corresponding
dibenzophospholes under metal-free conditions. The starting substrates
are readily available and easy-to-handle phosphine oxides, and the
regioselectivity is controlled by the innate electronic nature. Thus,
this newly developed protocol can provide concise and complementary
approach to the highly π-conjugated dibenzophospholes of potent
interest in material chemistry.
Autosomal dominant hypocalcemia can be caused by activating mutations of the calcium-sensing receptor (CaSR) gene. We experienced two patients (proband and her daughter) with hypocalcemia caused by a missense mutation of the CaSR gene. The proband, aged 25, showed hypocalcemia and hypoparathyroidism from infancy. She had been diagnosed as having idiopathic hypoparathyroidism and had been treated with calcitriol. She gave birth to a female infant at age 24 years. Her daughter was found to have hypocalcemia (Ca, 6.6 mg/dl), without seizure or tetany, when she was 7 months old. DNA analysis of their CaSR genes showed a novel heterozygous mutation at codon 129 (TGC-to-AGC) with substitution of cysteine for serine (C129S). Familial examination revealed that this mutation had occurred de-novo in the proband. Wild-type and mutant (C129S) CaSR cDNA were transfected into HEK293 cells, and intracellular calcium concentrations were measured with a fluorescent calcium indicator. HEK cells transfected with the C129S mutant CaSR gene showed a larger increase in intracellular calcium concentration in response to the change in the extracellular calcium concentration than HEK cells transfected with the wild-type receptor. We conclude that the C129S mutation in the CaSR gene observed in these patients causes autosomal dominant hypocalcemia.
This study provides an analysis of the clinical efficacy of influenza vaccination in a large cohort of nursing home residents in JAPAN: Annual influenza vaccine administration requires the attention of all nursing home attendants, physicians, and public health organizations.
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