Synthesis of CF2H‐Containing Oxime Ethers Derivatives from ClCF2H,tert‐Butyl Nitrile and Indoles

Summaryof main observation and conclusion A new and intriguing methodology to access various O-difluoromethylation oxime compounds from CICF2H,TBN and indoles is developed under mild reaction conditions.This strategy can suppress N-difluoromethylation of indoles successfully,in which there are two different active species(:CF2and·NO)while indoles are unprotected,featuringsimple operation and radical involvement.     

Synthesis of novel glycopeptide-polyoxazoline block copolymers by direct coupling between living anionic and cationic polymerization systems

A novel glycopeptide-containing block copolymer, poly[O-(tetra-O-acetyl-β-D -glucopyranosyl)-L -serine]-block-poly(2-methyl-2-oxazoline) ( 5 ), was synthesized by mutual termination of living polymerizations of a sugar-substituted α-amino acid N-carboxyanhydride (NCA) ( 1 ) and 2-methyl-2-oxazoline ( 3 ). 5 was deacetylated to provide the glycopeptide-polyoxazoline block copolymer, poly[O-(β-D -glucopyranosyl)-L -serine]-block-poly(2-methyl-2-oxazoline) ( 6 ).     

Stereospecific and asymmetric polymerization of 1-phenyldibenzosuberyl methacrylate with radical and anionic initiators

Stereospecific and asymmetric (helix-sense-selective) polymerization of 1-phenyldibenzosuberyl methacrylate (PDBSMA) was performed with radical and anionic initiators. A highly isotactic polymer having triad isotacticity greater than 97% was obtained by radical polymerization with (i-PrOCOO)₂ at 40°C. The radical polymerization of PDBSMA in (+)- and (-)-menthol gave (-)-and (+)-polymers, respectively, whose optical activity is ascribed to the prevailing one-handed helical conformation of a polymer chain. The radical copolymerization of PDBSMA with a small amount of an optically active monomer, (+)-phenyl-2-pyridyl-o-tolylmethyl methacrylate, afforded an optically active copolymer with the prevailing one-handed helical structure of PDBSMA sequences. Asymmetric anionic polymerization of PDBSMA was carried out with the complex of N, N′-diphenylethylenediamine monolithium amide and a chiral ligand, (+)-1-(2-pyrrolidinylmethyl)pyrrolidine in toluene at −78°C. The obtained polymer was highly isotactic and optically active due to nearly 100% one-handed helical structure.     

Relationship between apparent diffusion coefficient and signal intensity in endometrial and other pelvic cysts

We evaluated whether apparent diffusion coefficient (ADC) value is more useful than signal intensity for differentiating endometrial cysts from other pelvic cysts. In an in vitro study, signal intensity and diffusion coefficients were measured in whole blood phantoms in which blood oxidation was gradually increased and concentration subsequently diluted. Although both signal intensity and diffusion value were largely affected by blood concentration, diffusion value was almost independent of blood oxidation and red blood cell lysis-related diminution of magnetic nonhomogeneity, both factors greatly affecting signal intensity on T1- and T2-weighted images. In an in vivo study, differentiation between endometrial and other pelvic cysts was attempted by means of ADC values and signal ratios of cysts to muscles on T1- and T2-weighted images (T1- and T2-ratios). Endometrial cysts tended to show lower T2-ratios, higher T1-ratios, and lower ADC values than other pelvic cysts (p < 0.001). However, ADC values were not correlated with T1- and T2-ratios (p < /0.15/). The ability of ADC value to discriminate between these two groups (discriminant rate, 91.4%) was higher than that of T2-ratio (71.4%) or T1-ratio (88.6%). If combined, ADC and T1-ratio (or T2-ratio) showed higher discriminant rate (94.3%) than the combination of T1- and T2 ratios (88.6%). ADC value might be useful for evaluating the blood concentration of a cystic lesion, because diffusion value is more closely related to blood concentration and almost independent of blood oxidation and red blood cell lysis that largely affect signal intensity.     

Effect of the partial covalency on the solubility of AgBr In α-AgI

The internal energy and free energy of α-AgI-type solid solution have been calculated. On the basis of this calculation, the solubility limit of AgBr in α-AgI has been discussed. The difference of the solubility of AgBr in β-AgI and of β-AgI in AgBr has been interpreted due to the variation of the vibrational entropy depending on the mean value of anion mass. The partial ionicity in these solid solutions has also been discussed.     

Interactions of enzymes and a lectin with a chitin-based graft copolymer having polysarcosine side chains

The molecular-recognition abilities of a water-soluble chitin derivative, chitin-graft-polysarcosine (2) were investigated using chitinase, lysozyme, and wheat germ agglutinin (WGA). The enzymatic degradabilities of 2 were evaluated using chitinase and lysozyme. The molecular weight of those compounds of 2 with a higher affinity toward water decreased rapidly, as compared with partially deacetylated chitin (1). The 1H NMR spectrum of the low-molecular-weight fraction, yielded after lysozymic hydrolysis, indicated that saccharide residues in the chitinous backbone were specifically recognized by the lysozyme, then beta-glycosidic linkages in the backbone were selectively hydrolyzed. Furthermore, the molecular-recognition ability of the chitinous backbone of graft copolymer 2 toward the lectin WGA was elucidated by the enzyme-linked lectin-binding assay (ELLA). It was revealed that the graft copolymer with a lower degree of substitution (DS) value efficiently interacted with WGA. Interestingly, a graft copolymer having longer polysarcosine side chains showed higher recognition ability toward WGA than that having short side chains.     

Improvement of pharmaceutical potential of all-trans retinoic acid with hydroxypropyl-��-cyclodextrin

2-Hydroxypropyl-??-cyclodextrin (HP-??-CyD) includes all-trans retinoic acid (RA), covering the double-bond area of RA with substituted hydroxypropyl groups on CyD ring, as proved by the nuclear Overhauser effect (NOE) between methylene protons on the hydroxypropyl groups and the proton on RA. The formation of an inclusion complex results in hydrophilicity and stability. The effect of RA/HP-??-CyD and that of RA without HP-??-CyD on wrinkle scores and skin elasticity during skin treatment were identical, and the cutaneous stimulus was reduced comparing with RA. The results indicated that the RA/HP-??-CyD complex should help to realize new approaches in skin rejuvenation therapy.