CHEMISTRY OF ANTI-HIV ACTIVE TRIMERIC PYRANONAPHTHO-QUINONE CONOCURVONE: SYNTHETIC STUDIES TOWARDS MONOMERIC TERETIFOLIONE B AND RELATED COMPOUNDS

Pyranonaphthoquinone natural products are widely distributed in plants and microorganisms and have diverse biological activities. Angular benzochromenes are a small class of natural products isolated from Conospermum and Pentas plants. Of these, conocurvone was isolated from Conospermum as a trimeric pyranonaphthoquinone that has potent anti-HIV activity. We have focused on the total synthesis of compounds that exhibit biological activity or whose activity is enhanced upon oligomerization. This review describes the discovery and biological activities of the trimeric pyranonaphthoquinone conocurvone and related compounds, as well as our and other researchers’ synthetic studies toward monomeric pyranonaphthoquinones.This work was partially supported by The Uehara Memorial Foundation, a Grant from Musashino Joshi-Gakuin, and JSPS KAKENHI Grant Number JP19K06975

Soluble CD26 is inversely Associated with Disease Severity in Patients with Chronic Eosinophilic Pneumonia

Backgrounds: CD26, a multifunctional T cell surface glycoprotein, is a type II transmembrane protein containing only six amino acid residues in its cytoplasmic region. In addition to its membrane form, CD26 exists in plasma in a soluble form (sCD26), which is thought to be the extracellular domain of the molecule cleaved from the cell surface. Recent studies indicated CD26 have an important role in the pathogenesis of asthma, known as Th2 like disease. The function of CD26 in the esosinophlic lung disease is not well understood.Methods: Serum sCD26 was determined by enzyme-linked Immunosorbent assay in patients with acute eosinophilic pneumonia, chronic eosinophilic pneumonia (CEP), and sarcoidosis, and in healthy volunteers, to establish its value for discriminating between disease entities and as marker of disease activity.Results: Soluble CD26 was signifi cantly reduced in CEP and was related to disease severity. In particular, sCD26 was inversely correlated with arterial oxygen tension in CEP.Conclusion: Serum levels of sCD26 might appear to be useful as a new marker of CEP disease activity

OPTICAL TRAPPING AND ORIENTATION MANIPULATION OF 2D INORGANIC MATERIALS USING A LINEARLY POLARIZED LASER BEAM

Because inorganic nanosheets, such as clay minerals, are anisotropic, the manipulation of nanosheet orientation is an important challenge in order to realize future functional materials. In the present study, a novel methodology for nanosheet manipulation using laser radiation pressure is proposed. When a linearly polarized laser beam was used to irradiate a niobate (Nb6O 4-17) nanosheet colloid, the nanosheet was trapped at the focal point so that the in-plane direction of the nanosheet was oriented parallel to the propagation direction of the incident laser beam so as to minimize the scattering force. In addition, the trapped nanosheet was aligned along the polarization direction of the linearly polarized laser beam

Radiation-Pressure-Induced Hierarchical Structure of Liquid-Crystalline Inorganic Nanosheets

Although hierarchical assemblies of colloidal particles add novel structure-based functions to systems, few local and on-demand colloidal structures have been developed. We have combined the colloidal liquid crystallinity of two-dimensional inorganic particles and laser radiation pressure to obtain a large hierarchical and local structure in a colloidal system. The scattering force of the laser beam converted the parallel nanosheet alignment to the direction of the incident laser beam. At the focal point, the nanosheet orientation depends on the electric field of the polarized laser beam. In contrast, a giant tree-ring-like nanosheet texture of more than 100 μm, and which is independent of the polarization direction, was organized at the periphery of the focal point. This organization resulted from a cooperative effect between the liquid-crystalline nanosheets, which indicates an effectiveness of optical manipulation to construct hierarchical colloidal structures with the aid of interparticle interactions

Highly diastereoselective silyl-modified Sakurai multicomponent reaction

Highly diastereoselective silyl-modified Sakurai multicomponent reactio

Diels-Alder reactions using 4,7-dioxygenated indanones as dienophiles for regioselective construction of oxygenated 2,3-dihydrobenz[f]indenone skeleton

Regioselective construction of 4,8,9-trioxygenated 2,3-dihydrobenz[f]indenones, key intermediates for the synthesis of kinamycin antibiotics, was achieved via Diels-Alder reactions (DAR) using 4,7-dioxygenated indanone-type compounds as dienophiles. Reaction of indanetrione with 1-methoxybutadiene gave a 1 : 1 mixture of undesired 4,5,9-trioxygenated 2,3-dihydrobenz[f]indenone and [4.4.3]propellane. The addition of Lewis acid did not affect the product ratio, whereas the use of the 6-bromoindanetrione exclusively afforded the latter propellane. On the other hand, DAR of benzyne derived from bromoindan and furan gave 5,8-epoxy-2,3-dihydrobenz[f]indene, which was subjected to acid-induced ring opening to give 2,3-dihydrobenz[f]indenone with undesired 4,5,9-trioxy functions

PREPARATION OF OPTICALLY ACTIVE 2,2－DISUBSTITUTED 5-HYDROXYCHROMENES BY ENZYMATIC RESOLUTION OF RACEMIC ESTERS

Enzymatic kinetic resolution of racemic esters of 2,2-disubstituted 5-hydroxychromenes was examined. Transesterification of acetate using Amano Lipase PS in the presence of t-BuOH was most effective to give the corresponding optically active acetate in 18% yield and 95% ee. The absolute configuration of the acetate was determined as R based on the conversion to teretifolione B with natural absolute configuration

Asymmetric Total Synthesis of Brasiliquinones B and C via Oxidative Cyclization of a Hydroquinone-Silyl Enol Ether Hybrid

The asymmetric total synthesis of angucycline antibiotics (S)-brasiliquinones B and C was accomplished. The benz[a]anthraquinone core was constructed via oxidative cyclization of a hydroquinone-silyl enol ether hybrid. The resultant pentacyclic acetal was converted to the silyl enol ether, which was treated with Pd(II)/O2 to afford brasiliquinone C, after multistep conversion including dehydrogenation, desilylation and deacetalization, and hydroquinone oxidation. The (S)-configuration of natural brasiliquinones was confirmed based on the stereochemical correlation with the synthetic products