Polymeric phosphonium salts as a novel class of cationic biocides. IV. Synthesis and antibacterial activity of polymers with phosphonium salts in the main chain

Polymers with phosphonium salts and different alkyl spacers in the main chain were prepared, and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. The antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds against each strain, and the effect of the molecular weight on the antibacterial activity was also observed for the compounds with the same spacer length. The antibacterial activity of the polymer samples bonded with different spacer lengths was found to increase with increasing the spacer length against both strains. © 1993 John Wiley & Sons, Inc.     

Coupling between Substituents as a Function of Cage Structure: Synthesis and Valence Ionized States of Bridgehead Disubstituted Parent and Hexafluorinated Bicyclo[1.1.1]pentane Derivatives C5X6Y2

He(I) photoelectron spectroscopy was used to examine the valence‐shell electronic structure of three new and seven previously known bicyclo[1.1.1]pentane derivatives, 1,3‐Y₂‐C₅X₆ (for X=H, Y=H, Cl, Br, I, CN; for X=F, Y=H, Br, I, CN). A larger series (X=H or F, Y=H, F, Cl, Br, I, At, CN) has been studied computationally with the SAC‐CI (symmetry‐adapted cluster configuration interaction) method. The outer‐valence ionization spectra calculated by the SAC‐CI method, including spin–orbit interaction, reproduced the experimental photoelectron spectra well, and quantitative assignments are given. When the extent of effective through‐cage interaction between the bridgehead halogen lone‐pair orbitals was defined in the usual way by orbital‐energy splitting, it was found to be larger than that mediated by other cages such as cubane, and was further enhanced by hexafluorination. The origin of the orbital‐energy splitting is analyzed in terms of cage structure, and it is pointed out that its relation to the degree of interaction between the bridgehead substituents is not as simple as is often assumed.     

Lithium ion solvation in room-temperature ionic liquids involving bis(trifluoromethanesulfonyl) imide anion studied by Raman spectroscopy and DFT calculations

The solvation structure of the lithium ion in room-temperature ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMI(+)TFSI(-)) and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP(+0TFSI(-)) has been studied by Raman spectroscopy and DFT calculations. Raman spectra of EMI(+)TFSI(-) and BMP(+)TFSI(-) containing Li(+)TFSI(-) over the range 0.144-0.589 and 0.076-0.633 mol dm(-3), respectively, were measured at 298 K. A strong 744 cm-1 band of the free TFSI(-) ion in the bulk weakens with increasing concentration of the lithium ion, and it revealed by analyzing the intensity decrease that the two TFSI(-) ions bind to the metal ion. The lithium ion may be four-coordinated through the O atoms of two bidentate TFSI(-) ions. It has been established in our previous work that the TFSI(-) ion involves two conformers of C(1) (cis) and C(2) (trans) symmetries in equilibrium, and the dipole moment of the C(1) conformer is significantly larger than that of the C(2) conformer. On the basis of these facts, the geometries and SCF energies of possible solvate ion clusters [Li(C(1)-TFSI(-))(2)](-), [Li(C(1)-TFSI(-))(C(2)-TFSI(-))](-), and [Li(C(2)-TFSI(-))(2)](-) were examined using the theoretical DFT calculations. It is concluded that the C(1) conformer is more preferred to the C(2) conformer in the vicinity of the lithium ion.     

Relative and absolute configuration of versipelostatin, a down-regulator of molecular chaperone GRP78 expression

[structure: see text] Versipelostatin is the first compound which specifically inhibits the expression of GRP78 and the resultant robust cell death under stress conditions, in contrast to the weak cytotoxicity under normal conditions. Versipelostatin consists of a macrocyclic aglycone with an alpha-acyltetronic acid and three sugar moieties. The relative and absolute configuration of the aglycone moiety was established to be 4S, 5S, 6R, 9S, 10S, 13S, 16R, 18R, 19R, 20R, 24R, 27R, and 29S utilizing NMR techniques.     

Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium

The scavenging reaction of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) or galvinoxyl radical (GO.) by a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H), was significantly accelerated by the presence of Mg(ClO4)2 in de-aerated methanol (MeOH). Such an acceleration indicates that the radical-scavenging reaction of 1H in MeOH proceeds via an electron transfer from 1H to the radical, followed by a proton transfer, rather than the one-step hydrogen atom transfer which has been observed in acetonitrile (MeCN). A significant negative shift of the one-electron oxidation potential of 1H in MeOH (0.63 V vs. SCE), due to strong solvation as compared to that in MeCN (0.97 V vs. SCE), may result in change of the radical-scavenging mechanisms between protic and aprotic media.     

Pd/light-accelerated atom-transfer carbonylation of alkyl iodides: applications in multicomponent coupling processes leading to functionalized carboxylic acid derivatives

The atom-transfer carbonylation reaction of various alkyl iodides thereby leading to carboxylic acid esters was effectively accelerated by the addition of transition-metal catalysts under photoirradiation conditions. By using a combined Pd/hν reaction system, vicinal C-functionalization of alkenes was attained in which α-substituted iodoalkanes, alkenes, carbon monoxide, and alcohols were coupled to give functionalized esters. When alkenyl alcohols were used as acceptor alkenes, three-component coupling reactions, which were accompanied by intramolecular esterification, proceeded to give lactones. Pd-dimer complex [Pd(2)(CNMe)(6)][PF(6)](2), which is known to undergo homolysis under photoirradiation conditions, worked quite well as a catalyst in these three- or four-component coupling reactions. In this metal/radical hybrid system, both Pd radicals and acyl radicals are key players and a stereochemical study confirmed the carbonylation step proceeded through a radical carbonylation mechanism.     

Assignment of the relative and absolute configurations of acyclic secondary 1,2-diols

The NMR profiles (¹³C-δ, ¹H-δ, ¹H(OH)-δ, and ³J_H,H) of syn- and anti-diols—3a,b in achiral solvents were found to be very similar to each other. Contrarily, their Δδ (Δδ=δ_(R,R)-2−δ_(S,S)-2) behaviors in chiral bidentate NMR solvent (R,R)- and (S,S)-BMBA-p-Me (2) were found to be significantly different. On the basis of this NMR characteristic, a method has been developed to predict both the relative and absolute configurations of acyclic secondary 1,2-diols.     

A Convenient Synthesis of 2,3‐Dihydro‐3‐methylidene‐1H‐isoindol‐1‐ones by Reaction of 2‐Formylbenzo­nitriles with Dimethyloxosulfonium Methylide

A facile method for the synthesis of 2,3‐dihydro‐3‐methylidene‐1H‐isoindol‐1‐one and its derivatives carrying substituent(s) at C(5) and/or C(6) has been developed. The reaction of 2‐formylbenzonitrile ( 1a ) with dimethyloxosulfonium methylide, generated by the treatment of trimethylsulfoxonium iodide with NaH in DMSO/THF at 0°, resulted in the formation of 2,3‐dihydro‐3‐methylidene‐1H‐isoindol‐1‐one ( 2a ) in 77% yield. Similarly, six 2‐formylbenzonitriles carrying substituent(s) at C(4) and/or C(5), i.e., 1b – 1g , also gave the corresponding expected products 2b – 2g in comparable yields.     

Synthesis of 2,4,8‐Trisubstituted 1,7‐Naphthyridines by the Reaction of 4‐(1‐Aryl‐2‐methoxyethenyl)‐3‐isocyanopyridines with Excess Organolithiums

A convenient method for the synthesis of 2,4,8‐trisubstituted 1,7‐naphthyridines 6 by the reaction of (E)‐4‐(1‐aryl‐2‐methoxyethenyl)‐3‐isocyanopyridines 4 , which could be easily prepared from commercially available 3‐aminopyridine via aroylation of lithium (4‐lithiopyridin‐3‐yl)pivalamide with N‐methoxy‐N‐methylbenzamides, with excess organolithiums has been developed.