The Teaching of Singing in Meiji Period : Mainly on the contents of teaching

Additional file 3: Fig. S4. Spontaneous gp120 shedding from cell surface. The susceptibility of gp41 mutants to spontaneously shed gp120 was determined by flow cytometry and ELISA as described previously [79]. Briefly, culture medium of transiently transfected envelope expressing cells was exchanged for fresh medium containing Brefeldin A (BioLegend) and 0.2 % Sodium azide. Cells were then incubated for 15 h at 37˚C, 5 % CO2. (a) Level of envelope expression before and after incubation was compared by staining with 2G12. (b) Amount of gp120 released during incubation was determined by gp120 capture ELISA. As a positive control, cells expressing WT envelope was incubated with 20 µg/ml sCD4, which trigger gp120 shedding. Cells expressing SIV Env (SIV) and no Env (No Env) were used as negative control. The results are shown as the means ± standard errors of four replicas

Gold-Catalyzed Cascade Cyclization of (Azido)ynamides: An Efficient Strategy for the Construction of Indoloquinolines

(Azido)ynamides were efficiently converted into indoloquinolines by the use of a gold catalyst. While ynamides bearing an allylsilane gave terminal alkenes, ynamides bearing a simple alkene gave cyclopropanes. This reaction proceeds through the formation of an α-amidino gold carbenoid

Gold-Catalyzed Cascade Reaction of Skipped Diynes for the Construction of a Cyclohepta[<i>b</i>]pyrrole Scaffold

A gold-catalyzed cascade reaction of skipped diynes (1,4-diynes) and pyrroles has been developed. This reaction proceeds by the consecutive regioselective hydroarylation of two alkynes with a pyrrole, followed by a 7-<i>endo</i>-<i>dig</i> cyclization to give 1,6-dihydrocyclo­hepta­[<i>b</i>]­pyrroles in good yields. The direct synthesis of cyclohepta­[<i>b</i>]­indoles using indole nucleophiles has also been reported

Total Synthesis and Stereochemical Revision of Stereocalpin A: Mirror-Image Approach for Stereochemical Assignments of the Peptide–Polyketide Macrocycle

Stereocalpin A is a cyclic depsipeptide with cytotoxic activity isolated from the Antarctic lichen <i>Stereocaulon alpinum</i>. Although a number of synthetic investigations of the unprecedented 12-membered macrocycle of stereocalpin A with a dipeptide segment and a polyketide substructure have been conducted, the configurational assignment has not been completed. In this study, we achieved the first total synthesis and stereochemical revision of stereocalpin A. To facilitate the comprehensive assessment of eight possible stereocalpin A isomers, four stereoisomers of polyketide precursors were conjugated with l-Phe-l-MePhe and d-Phe-d-MePhe dipeptides (MePhe: <i>N</i>-methylphenylalanine) to provide four possible isomers and four mirror-image structures of the remaining isomers, respectively. The comparative NMR analysis of a series of stereoisomers revealed that stereocalpin A possesses 2<i>R</i>,4<i>S</i>,5<i>R</i>-configurations, which is unique among the related 12-membered hybrid peptide–polyketide natural products reported recently. The NOE correlations in the polyketide substructure of stereocalpin A were also retrospectively analyzed among the eight possible stereoisomers

Gold(I)-Catalyzed Oxidative Cascade Cyclization of 1,4-Diyn-3-ones for the Construction of Tropone-Fused Furan Scaffolds

Gold­(I)-catalyzed cascade cyclization of 1,4-diyn-3-ones with a pyridine <i>N</i>-oxide enabled direct construction of a benzo­[6,7]­cyclohepta­[1,2-<i>b</i>]­furan scaffold with the formation of four bonds. This reaction would proceed through oxidative cyclization, alkynyl migration, and 5-<i>endo-dig</i> type cyclization. Synthesis of benzotropone-fused naphtho­[1,2-<i>b</i>]­furans through a two-step sequence, including epoxidation and In­(OTf)₃-catalyzed intramolecular carbon–carbon bond formation, is also presented

Total Synthesis of (+)-Conolidine by the Gold(I)-Catalyzed Cascade Cyclization of a Conjugated Enyne

A total synthesis of (+)-conolidine has been achieved via the gold­(I)-catalyzed cascade cyclization of a conjugated enyne. Remarkably, this strategy allowed for the simultaneous formation of the indole ring and the ethylidene-substituted piperidine moiety of (+)-conolidine under homogeneous gold catalysis in an enantioselective manner (88–91% ee)

Gold-Catalyzed Three-Component Annulation: Efficient Synthesis of Highly Functionalized Dihydropyrazoles from Alkynes, Hydrazines, and Aldehydes or Ketones

Polysubstituted dihydropyrazoles were directly obtained by a gold-catalyzed three-component annulation. This reaction consists of a Mannich-type coupling of alkynes with <i>N</i>,<i>N</i>′-disubstituted hydrazines and aldehydes/ketones followed by intramolecular hydroamination. Cascade cyclization using 1,2-dialkynylbenzene derivatives as the alkyne component was also performed producing fused tricyclic dihydropyrazoles in good yields

Synthesis of Fused Carbazoles by Gold-Catalyzed Tricyclization of Conjugated Diynes via Rearrangement of an <i>N</i>‑Propargyl Group

Various <i>N</i>-propargylanilines bearing a conjugated diyne moiety at the 2-position were converted to tetracyclic fused carbazoles by treatment with a homogeneous gold­(I) catalyst. This cascade reaction proceeds through indole formation with concomitant rearrangement of the <i>N</i>-propargyl group, intramolecular nucleophilic addition toward the resulting allene moiety, and subsequent hydroalkenylation. This transformation enables a one-pot synthesis of fused carbazoles from readily accessible substrates with 100% atom economy

Direct Construction of Fused Indoles by Gold-Catalyzed Cascade Cyclization of Conjugated Diynes

A gold-catalyzed cascade cyclization of aniline derivatives bearing a conjugated diyne moiety was developed. Following the 5-<i>endo-dig</i> indole formation, subsequent 7-<i>endo-dig</i> cyclization predominated over 6<i>-exo-dig</i> cyclization to give the indole fused with a seven-membered ring in good yields

Optimized Method of G‑Protein-Coupled Receptor Homology Modeling: Its Application to the Discovery of Novel CXCR7 Ligands

Homology modeling of G-protein-coupled seven-transmembrane receptors (GPCRs) remains a challenge despite the increasing number of released GPCR crystal structures. This challenge can be attributed to the low sequence identity and structural diversity of the ligand-binding pocket of GPCRs. We have developed an optimized GPCR structure modeling method based on multiple GPCR crystal structures. This method was designed to be applicable to distantly related receptors of known structural templates. CXC chemokine receptor (CXCR7) is a potential drug target for cancer chemotherapy. Homology modeling, docking, and virtual screening for CXCR7 were carried out using our method. The predicted docking poses of the known antagonists were different from the crystal structure of human CXCR4 with the small-molecule antagonist IT1t. Furthermore, 21 novel CXCR7 ligands with IC₅₀ values of 1.29–11.4 μM with various scaffolds were identified by structure-based virtual screening