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This paper addresses the geometry distortion of orthoquinone-containing phenacene-type compounds by comparing the structures of phenanthrene-9,10-dione, chrysene-5,6-dione, and picene-13,14-dione. Interestingly, the calculated geometry of chrysene-5,6-dione under the isolated state was drastically different from the experimental one observed by single-crystal X-ray analysis. Theoretical calculations suggested that the molecular geometry of the o -quinone derivatives was sensitive not only to the sterically intramolecular proximity between the carbonyl oxygen and the hydrogen atoms of the benzene rings but also to intermolecular interactions. The twist distortion affects properties such as oscillator strength and 1-electron transitions, for low-lying excited states. [ABSTRACT FROM AUTHOR]

Author(s): Hiroaki Murata [sup.1], Akihiro Yokoyama [sup.1], Tetsuya Hara [sup.1] Author Affiliations: (1) grid.174567.6, 0000 0000 8902 2273, Department of Anesthesiology and Intensive Care Medicine, Nagasaki University Graduate School of [...]

Author(s): Hiroaki Murata [sup.1], Akihiro Yokoyama [sup.1], Tetsuya Hara [sup.1] Author Affiliations: (1) grid.174567.6, 0000 0000 8902 2273, Department of Anesthesiology and Intensive Care Medicine, Nagasaki University Graduate School of [...]

While the number of private electrical facilities is increasing, there are not enough security personnel to perform the security work. In this paper, we propose a random forest model for predicting leakage current alarms in order to improve the efficiency of electrical safety operations. A random forest was created using periodic inspection data, alarm data, and meteorological data as explanatory variables, and generalization performance was evaluated by OOB-based F-measure. In order to obtain the highest performance, a grid search was performed to optimize the hyperparameters. As a result, it was possible to achieve alarm prediction with a certain level of performance. In addition, the optimal hyperparameters were found by grid search, and the F-measure was improved.

The mechanism of the chain-growth polymerization of 2-bromo-5-chloromagnesio-3-hexylthiophene (1) with Ni[(d1,3-bis-(diphenylphosphino)propane]Cl2, in which head-to-tail poly(3-hexylthiophene) (HT-P3HT) with a low polydispersity is obtained. This chain-growth polymerization involves the coupling reaction of (1) with the polymer through the Ni catalyst, which is transferred intramolecularly to the terminal C-Br bond of the elongated molecule, called 'catalyst transfer polycondensation'.

Superacid-catalyzed Pictet-Spengler reactions of imines of 2-phenethylamine to produce the parent and 1-substituted 1,2,3,4-tetrahydroisoquinolines in moderate to high yields are discussed. A linear relationship between the acidity of the reaction media in kinetic studies of N-methylene-2-phenethylamine and the rate of cyclization was found. Results indicate that the prototype Pictet-Spengler cyclization of N-methylene-2-phenethylamine can occur both through the dication and the monocation reaction.

A carotenoid biosynthesis gene cluster for the manufacture of astaxanthin in the marine bacterium Agrobacterium aurantiacum is studied. The cluster has five carotenogenic genes which have similar orientations and are called crtW, crtZ, crtY, crtI, and crtB. The crtW and crtZ gene products, which facilitated oxygenation to convert beta-carotene to astaxanthin, have low substrate specificity, enabling the manufacture of astaxanthin intermediates.

A study was done on the structure of maitotoxin which is derived from cultures of dinoflagellates treated with NaIO4 and NaBH4. Results show that the toxin is a C142 carbon chain of composition C164H256O68S2Na2 with a molecular weight of 3422. It has 32 ether rings, 28 hydroxyl groups and two sulfate esters. Most of the ether rings are trans-fused except for rings L/M and N/O which exhibits cis-fusion.

Spectroscopic measurements of the partial structure of maitotoxin (MTX) showed that 30 ether rings, 30 hydroxyls, 21 methyls and 2 sulfate esters comprise the polyether skeleton of the marine toxin. This structure was identified through extensive examination of the periodate degradation products of the extract from the dinoflagellate, Gambierdiscuc toxicus. Also, the examination reveals that the toxin molecule exhibits dual polarity due to the hydrophilic and hydrophobic properties of its segments.

The Suzuki-Miyaura coupling reaction that can be effectively used for the chain-growth polymerization to produce compounds like polyfluorene from an externally added initiator unit is described. The polycondensation is found to proceed in a chain-growth manner from the initiator unit derived from the catalyst.

The synthesis of poly-(p-phenylene) (PPP) is investigated to see whether a monomer containing no heteroatom in the aromatic ring undergoes catalyst-transfer poly-condensation. It is demonstrated that the Ni-catalyzed polycondensation of 1-bromo-4-chloromagnesio-2,5-dihexyloxybenzene proceeds by a chain-growth mechanism to afford PPP with a narrow polydispersity and that the molecular weight of PPP is controlled by the feed ratio of the monomer to the Ni catalyst.

Poly(p-benzamide)s bearing a chiral side chain on the nitrogen atom were synthesized by chain-growth polycondensation methodology. The results of X-ray crystallographic analysis of 4-(methylamino)benzoic acid oligomers substantiated that they have a helical conformation with three monomer units per turn.

The chain-growth polycondensation method for well defined aromatic polyamides has been developed for the synthesis of poly(p-benzamide) with a low polydispersity by the polycondensation of phenyl 4-(4-octyloxybenzylamino)-benzoate followed by deprotection with TFA. The self-assembly of block copolymers and star polymers containing the well-defined poly(p-benzamide) units will be versatile protocol for nanoarchitectures of aromatic polyamides.

A successful chain-growth polycondensation of meta-substituted monomers, 3-(octylamino) benzoic acid esters that yield poly(m-benzamide)s with well-defined molecular weights and low polydispersities is reported. The inductive effect of the nucleophilic site on the reactivity of the electrophilic site at the meta position of the monomer is as applicable to chain-growth polycondensation as is the resonance effect of the para-substituted monomers.

Background: Pseudocowpox virus (PCPV) infects cattle worldwide with zoonotic potential but has not been isolated in Japan. Thus, the epidemiological status of PCPV infection in cattle is undetermined. Results: In May 2016, a cattle in a farm in Yamaguchi Prefecture showed white vesicles and hyperemia in the mucosa under the tongue surface, but not on the teats and coronary cushions. A parapoxvirus was isolated from the oral lesion swab and was genetically characterized based on the full-length sequence of B2L gene encoding viral envelope. Phylogenetic analysis showed that the isolated virus was classified into PCPV. Conclusion: This case indicates its potential spread in Japan. This is the first report of isolation of PCPV in Japan. [ABSTRACT FROM AUTHOR]

ABSTRACT To synthesize ladder-type polyamides by construction of two amide bonds successively, 2,5-diaminoterephthalic acid derivatives bearing anthranilic acid ester and isatoic anhydride moieties were synthesized and their polymerization was investigated. Polymerization of the methyl ester monomer proceeded in the presence of lithium hexamethyldisilazide (LiHMDS) as a base in tetrahydrofuran (THF). However, mass spectroscopic analysis of the product suggested that not only the bis(trimethylsilyl)amide anion of LiHMDS but also the methoxide anion eliminated at the second amide-linkage formation reaction decomposed the isatoic anhydride unit of the growing oligomer by nucleophilic attack to disturb the polymerization. To reduce the nucleophilicity of the eliminated anion, methyl ester of the monomer was changed to phenyl ester and its polymerization was studied. The reaction conditions were optimized, and the best result was obtained when the polymerization was conducted in the presence of 1.0 equivalent of LiHMDS without additives in THF at 50 °C. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 2365-2372 [ABSTRACT FROM AUTHOR]

A 74-year-old woman with right-sided palatal swelling was diagnosed with mucosa-associated lymphoid tissue (MALT) lymphoma on palatal biopsy. In patients with pulmonary MALT lymphoma, the most frequent parenchymal findings of chest CT are consolidations (~55%), nodules (~55%) and masses (~50%). [Extracted from the article]

ABSTRACT Isopropyl-substituted tri(ethylene glycol) is used as a chiral side chain of N-substituted poly( p-benzamide) in order to increase the difference of stability between the right- and left-handed helical structures of the polymer. The target polymer is synthesized by the chain-growth condensation polymerization of the corresponding monomer with an initiator using lithium 1,1,1,3,3,3-hexamethyldisilazide as a base. A circular dichroism (CD) study of the polymer reveals that the CD signal is due to an excess of a thermodynamically controlled right-handed helical structure of the polymer, and that the replacement of the methyl group with a bulkier isopropyl group at the side chain of poly( p-benzamide) increases the abundance of right-handed helical structure in chloroform. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1623-1628 [ABSTRACT FROM AUTHOR]

ABSTRACT Application of chain-growth condensation polymerization (CGCP) to obtain well-defined polybenzoxazole (PBO) was examined. CGCP of both phenyl 3-{(2-methoxyethoxy)methoxy (MEM-oxy)}-4-(octylamino)benzoate ( 1b) ( para-substituted monomer) and phenyl 4-MEM-oxy-3-(octylamino)benzoate ( 3b) ( meta-substituted monomer) was examined in the presence of metal disilazide base and phenyl 4-nitro- or methylbenzoate 2 as an initiator. Polymerization of the latter monomer, but not the former, afforded polymer with controlled molecular weight based on the feed ratio of monomer to initiator and with a narrow molecular weight distribution. Accordingly, monomer 3c, in which the octyl group on the amino nitrogen of 3b was replaced with a 4-(octyloxy)benzyl (OOB) group, was polymerized in the presence of lithium 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS), phenyl 4-methylbenzoate ( 2b), and LiCl in THF at 0 °C to yield poly 3c with well-defined molecular weight ( Mn = 4520-9080) and low polydispersity ( Mw/ Mn ≤ 1.11). Treatment of poly 3c with trifluoroacetic acid simultaneously removed the MEM and OOB groups, affording poly( o-hydroxyamide) (poly 4) without scission of the amide linkages. Cyclodehydration of poly 4 proceeded at 350 °C to yield PBO (poly 5), which was insoluble in organic solvents and acids. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1730-1736 [ABSTRACT FROM AUTHOR]

ABSTRACT Well-defined poly(3-alkyl-4-benzamide) was synthesized by means of chain-growth condensation polymerization of phenyl 3-octyl-4-(4-octyloxybenzyl(OOB)amino)benzoate ( 1c) from initiator 2, followed by removal of the OOB groups on amide nitrogen of poly 1c. Polymerization of 1c with phenyl 4-(trifluoromethyl)benzoate ( 2b) in the presence of 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS) and LiCl in THF at −10 °C gave poly 1c with a narrow molecular weight distribution ( Mw/ Mn ≤ 1.08) and a well-defined molecular weight ( Mn = 4480-12,700) determined by the feed ratio of monomer to initiator (from 10 to 30). The OOB groups of poly 1c were removed with H2SO4 to give the corresponding N-unsubstituted poly( p-benzamide) (poly 1c′) with low polydispersity. The solublity of poly 1c′ in polar organic solvents was dramatically higher than that of poly( p-benzamide), demonstrating that introduction of an alkyl group on the aromatic ring is very effective for improving the solubility of poly( p-benzamide). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 360-365 [ABSTRACT FROM AUTHOR]

Condensation reaction of poly(ethylene glycol) (PEG) with a carboxyl group at one chain end and hyperbranched polyamide (HBPA) with a hydroxyl group at the focal point was performed in the presence of condensation agent at ambient temperature, yielding PEG ‐ b ‐ HBPAs with defined molecular weight and very narrow molecular weight distribution. PEG ‐ b ‐ HBPA formed micelles in water. [ABSTRACT FROM AUTHOR]

PolystyrENe ‐ graft ‐ poly(p ‐ bENzamide) was synthesized by free radical copolymerization of poly(N ‐ octyloxybENzyl ‐ p ‐ bENzamide) macromonomer and styrENe, followed by the removal of the octyloxybENzyl groups from amide nitrogEN. The glass transition temperature (Tg) of polystyrENe ‐ graft ‐ poly(p ‐ bENzamide) increased dramatically by 50–60 °C whEN the contENt of poly(p ‐ bENzamide) exceeded a threshold of about 4%. [ABSTRACT FROM AUTHOR]

Well-defined (AB)3 type star block copolymer consisting of aromatic polyether arms as the A segment and polystyrene (PSt) arms as the B segment was prepared using atom transfer radical polymerization (ATRP), chain-growth condensation polymerization (CGCP), and click reaction. ATRP of styrene was carried out in the presence of 2,4,6-tris(bromomethyl)mesitylene as a trifunctional initiator, and then the terminal bromines of the polymer were transformed to azide groups with NaN3. The azide groups were converted to 4-fluorobenzophenone moieties as CGCP initiator units by click reaction. However, when CGCP was attempted, a small amount of unreacted initiator units remained. Therefore, the azide-terminated PSt was then used for click reaction with alkyne-terminated aromatic polyether, obtained by CGCP with an initiator bearing an acetylene unit. Excess alkyne-terminated aromatic polyether was removed from the crude product by means of preparative high performance liquid chromatography (HPLC) to yield the (AB)3 type star block copolymer ( Mn = 9910, Mw/ Mn = 1.10). This star block copolymer, which contains aromatic polyether segments with low solubility in the shell unit, exhibited lower solubility than A2B or AB2 type miktoarm star copolymers. In addition, the obtained star block copolymer self-assembled to form spherical aggregates in solution and plate-like structures in film. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

Kumada-Tamao coupling polymerization of 6-bromo-3-chloromagnesio-2-(3-(2-methoxyethoxy)propyl)pyridine 1 with a Ni catalyst and Suzuki-Miyaura coupling polymerization of boronic ester monomer 2, which has the same substituted pyridine structure, with tBu3PPd( o-tolyl)Br were investigated for the synthesis of a well-defined n-type π-conjugated polymer. We first carried out a model reaction of 2,5-dibromopyridine with 0.5 equivalent of phenylmagnesium chloride in the presence of Ni(dppp)Cl2 and then observed exclusive formation of 2,5-diphenylpyridine, indicating that successive coupling reaction took place via intramolecular transfer of Ni(0) catalyst on the pyridine ring. Then, we examined the Kumada-Tamao polymerization of 1 and found that it proceeded homogeneously to afford soluble, regioregular head-to-tail poly(pyridine-2,5-diyl), poly(3-(2-(2-(methoxyethoxy)propyl)pyridine) (PMEPPy). However, the molecular weight distribution of the polymers obtained with several Ni and Pd catalysts was very broad, and the matrix-assisted laser desorption ionization time-of-flight mass spectra showed that the polymer had Br/Br and Br/H end groups, implying that the catalyst-transfer polymerization is accompanied with disproportionation. Suzuki-Miyaura polymerization of 2 with tBu3PPd( o-tolyl)Br also afforded PMEPPy with a broad molecular weight distribution, and the tolyl/tolyl-ended polymer was a major product, again indicating the occurrence of disproportionation. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

Condensation polymerization of 5-aminoisophthalic acid methyl ester 1 bearing a N-tri(ethylene glycol) methyl ester (TEG) chain as an AB2 monomer was conducted and the properties of the resulting hyperbranched polyamides (HBPA) were investigated. When the polymerization of 1 was carried out with N-methyl core initiator 2b at various feed ratios of 1 to 2b ([1]0/[2b]0) in the presence of LiHMDS and LiCl at -10 °C, the Mn values of the obtained HBPA increased in proportion to the [1]0/[2b]0 ratio from 7 to 46 (Mn = 3810-18600), retaining a narrow molecular weight distribution (Mw/Mn = 1.11-1.19). The HBPA was soluble in water, and a 0.25 wt.-% aqueous solution of the HBPA exhibited a lower critical solution temperature (LCST). The cloud point was 21-23 °C, which is about 30 °C lower than that of the corresponding poly(m-benzamide) with the N-TEG unit. [ABSTRACT FROM AUTHOR]

A new regioregular head-to-tail (HT)-type polypyridine with methoxyethoxyethoxy (MEEO) side chains, HT-PMEEOPy, was synthesized by means of Kumada-Tamao coupling polymerization of a Grignard monomer with a Ni catalyst. Although the polymer was precipitated in THF during polymerization, multiangle laser light scattering (MALLS) analysis indicated that the weight-average molecular weight ( Mw) was about 25,000. The HT content in the polymer was 95%. A solution of HT-PMEEOPy in CHCl3 was found to emit a strong blue light when the solution was irradiated with UV light; the UV-vis absorption maximum (λmax) and photoluminescence maximum (λmax em) were at 392 and 460 nm, respectively. To clarify the effect of regioregularity of PMEEOPy on the photoluminescence, head-to-head (HH) PMEEOPy was synthesized by means of Yamamoto coupling polymerization. The photoluminescence of HH-PMEEOPy (λmax = 330 nm, λmax em = 414 nm) was weaker than that of HT-PMEEOPy. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

Ni-catalyzed Kumada–Tamao coupling polymerizationof 5-bromo-3-chloromagnesio-2-(2-(2-methoxyethoxy)ethoxy)pyridine(1) was investigated. Monomer 1, which wasobtained quantitatively by treatment of the corresponding bromoiodopyridine 3with 1.0 equiv of iPrMgCl at0 °C, was polymerized with Ni(dppp)Cl2(dppp = 1,3-bis(diphenylphospino)propane))in the presence of 2.0 equiv of LiCl in THF at room temperature toyield poly(2-(2-(2-methoxyethoxy)ethoxy)pyridine-3,5-diyl) (m-PMEEOPy) with narrow polydispersity. The Mnvalue was controlled by the feed ratio of the monomerprecursor 3to Ni(dppp)Cl2. MALDI-TOF massspectra showed that m-PMEEOPy uniformly had a bromineatom at one end and a hydrogen atom at the other. Both end groupscould be converted to aryl groups by addition of an excess of arylmagnesium chloride to the reaction mixture after completion of thepolymerization. These results indicate that the polymerization of 1with Ni(dppp)Cl2involves the intramolecularcatalyst-transfer polymerization mechanism. [ABSTRACT FROM AUTHOR]

Condensation polymerization of 6-( N-substituted-amino)-2-naphthoic acid esters ( 1) was investigated as an extension of chain-growth condensation polymerization (CGCP). Methyl 6-(3,7-dimethyloctylamino)-2-naphthoate ( 1b) was polymerized at −10 °C in the presence of phenyl 4-methylbenzoate ( 2) as an initiator and lithium 1,1,1,3,3,3-hexamethyldisilazide (LiHMDS) as a base. When the feed ratio [ 1a]0/[ 2]0 was 10 or 20, poly(naphthalenecarboxamide) with defined molecular weight and low polydispersity was obtained, together with a small amount of cyclic trimer. However, polymer was precipitated during polymerization under similar conditions in [ 1a]0/[ 2]0 = 34. To increase the solubility of the polymer, monomers 1c and 1d with a tri(ethylene glycol) (TEG) monomethyl ether side chain instead of the 3,7-dimethyloctyl side chain were synthesized. Polymerization of the methyl ester monomer 1c did not proceed well, affording only oligomer and unreacted 1c, whereas polymerization of the phenyl ester monomer 1d afforded well-defined poly(naphthalenecarboxamide) together with small amounts of cyclic oligomers in [ 1d]0/[ 2]0 = 10 and 29. The polymerization at high feed ratio ([ 1d]0/[ 2]0 = 32.6) was accompanied with self-condensation to give polyamide with a lower molecular weight than the calculated value. Such undesirable self-condensation would result from insufficient deactivation of the electrophilic ester moiety by the electron-donating resonance effect of the amide anion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]