Pd‐initiated polymerization of diazo compounds bearing dialkoxyphosphinyl group and hydrolysis of the resulting polymers and oligomers to afford phosphonic acid‐containing products

Pd‐initiated polymerization and oligomerization of diazo compounds containing a dialkoxyphosphinyl group are described. Polymerization of 2‐dialkoxyphosphinylethyl diazoacetates with π‐allylPdCl‐based initiating systems afforded C? C main chain polymers bearing phosphonate on each main chain carbon atom. The quantitative transformation of the side chain phosphonate to phosphonic acid resulted in the formation of water soluble polymers having the acid groups accumulated around their main chains, although the carbonyl ester linkage in the side chain was cleaved via intramolecular acid‐assisted hydrolysis in water at 80 °C. Pd‐initiated oligomerization of diethyl diazomethylphosphonate yielded an oligomeric product bearing diethoxyphosphiny groups directly attached to its main chain carbons, with unexpected incorporation of azo group in the main chain framework. Hydrolysis of the phosphonate of the oligomer afforded a water‐soluble product, which was revealed to show higher proton conductivity than poly(vinylphosphonic acid) under certain conditions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1742–1751     

Dynamic recording of a digital hologram with single exposure by a wave-splitting phase-shifting method

The wave-splitting phase-shifting digital holography using a pixelated microretarder array is proposed. By using four intensity images recorded by the pixelated microretarder array, Stokes parameters of the incident wave can be calculated. The fully complex amplitude distribution of the object wave can be obtained by using Stokes parameters, if the polarization states of the object and reference waves are linear and orthogonal. Two sets of experimental results are provided to verify the feasibility of the proposed method. One is the result for a movie recording using a CW laser and the other is the result for instant recording using a single pulsed laser.     

Drug–tea polyphenol interaction

Propericiazine (PCZ) is an antipsychotic agent used for the treatment and the prevention of relapse of schizophrenia. We found that when an oral solution containing PCZ was mixed with a green tea drink, the residual content of PCZ was reduced by forming an insoluble complex between PCZ and tea polyphenol. In this study, the mechanism underlying the incompatibility of PCZ with green tea polyphenol (GTP) in the solution was clarified by isothermal titration microcalorimetry (ITC). Both solutions of 27.4 mM PCZ and 2.2 mM (?)-epigallocatechin gallate (EGCg), which is a main ingredient of GTP, were mixed and then PCZ in the filtrate was reduced to approximately 60 %. According to measurement at 298 K by ITC, PCZ formed an insoluble complex with EGCg at an associate constant (K) of 4.75 × 10² M^?1 exothermically, ΔH = ?40.0 kJ mol^?1. When (?)-epicatechin gallate (ECg) was used as the GTP, PCZ interacted with ECg with K and ΔH values of 3.74 × 10² M^?1 and ?22.1 kJ mol^?1, respectively. On the other hand, little heat of the reaction between PCZ and (?)-epigallocatechin or (?)-epicatechin was observed. The results indicated that the main reason for this incompatibility was the formation of an insoluble complex by PCZ and a gallate-type GTP such as EGCg and ECg in the aqueous solution.     

Hydrochlorothiazide Enhances UVA‐Induced DNA Damage

The UVA is currently thought to be carcinogenic because, similar to UVB, it induces the formation of cyclobutane pyrimidine dimers (CPDs). Various drugs have been reported to cause photosensitive drug eruptions as an adverse effect. Although the precise mechanism of photosensitive drug eruption remains to be elucidated, it is generally accepted that free radicals and other reactive molecules generated via UV‐irradiated drugs play important roles in the pathogenesis of photosensitive drug eruptions. The waveband of concern for photo‐reactive drugs is UVA‐visible light, but some extend into the UVB region. We tested whether photosensitive drugs could enhance CPD formation after UVA exposure by using isolated DNA in the presence of several reported photosensitive drugs using high‐performance liquid chromatography. We found that the diuretic agent hydrochlorothiazide (HCT) significantly enhanced the production of TT dimers over a wide range of UVA. Furthermore, we investigated whether UVA plus HCT could enhance CPD production in xeroderma pigmentosum model mice defective in nucleotide excision repair. Immunofluorescence studies showed that CPD formation in the skin significantly increased after 365 nm narrow‐band UVA irradiation in the presence of HCT, compared with that in wild‐type mice. HCT could be used with caution because of its enhancement of UVA‐induced DNA damage.     

Photoswitchable organocatalysis in acylation of alcohol using dithienylethene-linked azoles

Three novel dithienylethenes bearing azole derivatives were synthesized and found to undergo reversible photocyclization of the dithienylethene units upon alternate irradiation with UV and visible light. Among them, the dithienylethene-linked imidazole and N-phenylimidazole exhibited a relatively high organocatalytic activity for the acylation of 2-decanol with acetic anhydride, and the catalytic activity of the dithienylethene-linked imidazole could be switched by reversible photoinduced cyclization/cycloreversion of the dithienylethene unit.     

First total synthesis of prunustatin A

In this study, we achieved the first total synthesis of natural prunustatin A (1), a novel inhibitor of glucose-regulated protein 78 (GRP78) expression. A key feature included a 15-membered ring macrocyclization, which was successfully accomplished by employing Shiina macrolactonization using 2-methyl-6-nitrobenzoic anhydride (MNBA) and 4-dimethylaminopyridine (DMAP).     

Copper‐Catalyzed CH Bond Direct Chalcogenation of Aromatic Compounds Leading to Diaryl Sulfides,Selenides, and Diselenides by Using Elemental Sulfur and Selenium as Chalcogen Sources Under Oxidative Conditions

The reactions of aromatic compounds and elemental chalcogens catalyzed by a copper salt with molecular oxygen as an oxidant were carried out. The reaction of 3‐substituted imidazo[1,5‐a]pyridines and elemental sulfur in the presence of CuTC (copper(I) thiophenecarboxylate) gave the corresponding bisimidazopyridyl sulfides in good to quantitative yields. The reaction proceeded even under aerobic oxidation conditions. The use of a polar solvent was crucial for the reaction, and DMSO (dimethyl sulfoxide) in particular stimulated the reaction. The reaction could be applied to common aromatic compounds, such as N‐methyl indole and dialkyl anilines. The reaction of indole proceeded at the nucleophilic C3 position rather than at the acidic C2 position. In addition, the reaction of dialkyl anilines proceeded with an ortho, para orientation. The reactions of imidazopyridines and elemental selenium under similar conditions gave the corresponding bisimidazopyridyl diselenides along with bisimidazopyridyl monoselenides. The resulting diselenides were readily converted to the corresponding monoselenides with unreacted imidazopyridines under the same conditions. The reaction could be applied to the copolymerization of bifunctional bisimidazopyridines and elemental sulfur to give oligomeric copolymers in quantitative yield.