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Abstract We introduce a versatile metal-organic framework (MOF) for encapsulation and immobilization of various guests using highly ordered internal water network. The unique water-mediated entrapment mechanism is applied for structural elucidation of 14 bioactive compounds, including 3 natural product intermediates whose 3D structures are clarified. The single-crystal X-ray diffraction analysis reveals that incorporated guests are surrounded by hydrogen-bonded water networks inside the pores, which uniquely adapt to each molecule, providing clearly defined crystallographic sites. The calculations of host-solvent-guest structures show that the guests are primarily interacting with the MOF through weak dispersion forces. In contrast, the coordination and hydrogen bonds contribute less to the total stabilization energy, however, they provide highly directional point interactions, which help align the guests inside the pore.

For exploring general routes to the pluramycinclass of antibiotics, including congeners with epoxide-bearing side chains, syntheses of kidamycinone and its epoxide (epoxykidamycinone) have been achieved. At the stage of the A-ring cyclization with alkene-bearing side chain, the desired 6-endo product was obtained as a major compound, although the corresponding undesired 5-exo product was also formed. [ABSTRACT FROM AUTHOR]

Photoinduced intramolecular redox reaction of naphthoquinone derivatives is described, enabling C-H bond oxygenation at the a-position of the quinone nucleus and the quinone reduction under photoirradiation. The substrate scope and mechanistic insight are reported. [ABSTRACT FROM AUTHOR]

The first enantioselective total syntheses of engelharquinone (2) and its epoxide 3 have been achieved. The key steps include (1) catalytic asymmetric 1,4-addition of a naphthylboronic acid derivative to a masked naphthoquinone derivative by using a chiral Rh-complex and (2) thiolate-promoted stereospecific construction of the bicyclo[3.2.1]octadienone scaffold. [ABSTRACT FROM AUTHOR]

Background: Several nuclear imaging and cerebrospinal fluid (CSF) biomarkers are under investigation, aimed at facilitating the differential diagnosis of dementias.Objective: To quantitatively synthesize data on test performance in differentiating dementia with Lewy bodies (DLB) from other dementias.Methods: We searched PubMed (January 2000- March 2015) for English-language publications that assessed a selected set of five imaging and three CSF biomarkers for this purpose. We meta-analyzed measures of agreement between biomarker results and clinical diagnosis.Results: Forty-five publications were eligible. The majority of evidence was based on studies that enrolled representative disease populations. For differentiating between DLB and Alzheimer's disease (AD) or other dementias, metaiodobenzylguanidine scintigraphy and dopamine transporter (DAT) single photon emission computed tomography (SPECT) showed, respectively, excellent (summary kappa = 0.85; 95% confidence interval [95% CI], 0.74-0.96) and good (summary kappa = 0.71; 95% CI, 0.43-0.99) agreement. Metaiodobenzylguanidine scintigraphy appeared superior to fluorodeoxyglucose- positron emission tomography (summary kappa = 0.53; 95% CI, 0.36-0.69) and cerebral blood flow SPECT (summary kappa = 0.40; 95% CI, 0.33-0.47). For differentiating DLB from AD, CSF t-tau levels (summary kappa = 0.68; 95% CI, 0.55-0.82) performed comparably to metaiodobenzylguanidine scintigraphy and DAT SPECT. Sparse direct comparative evidence failed to corroborate these indirect comparisons.Conclusion: Metaiodobenzylguanidine scintigraphy and DAT SPECT are highly concordant with clinical diagnosis in differentiating DLB from other dementias. However, given the limitations in the study design, the applicability of these results to real-world differential diagnosis remains unclear. Prospective studies targeting patients with atypical presentations that adopt gold standard tests would reliably estimate the true test performance of these promising biomarkers. [ABSTRACT FROM AUTHOR]

In connection with the total synthesisof naphthospironone A, amodel study has revealed a promising approach to construct a benzobicyclo[3.2.1]octeneskeleton possessing an oxaspirocycle by employing an intramolecularaldol cyclization. [ABSTRACT FROM AUTHOR]

A novel and efficient synthesis of xanthones is described. 2-(Trimethylsilyl)phenyl 2-fluorobenzoate derivatives undergo Fries-type rearrangement and intramolecular SNAr reaction in a one-pot sequential manner under fluoride ion-promoted mild conditions. The method provides efficient access to xanthones that have significant steric congestion around the C9 carbonyl, which are not readily available by conventional methods. [ABSTRACT FROM AUTHOR]